Integrated Circuit LM2577

L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013L M 1 5 7 7 / L M 2 5 7 7S I M P L ES W I T C H E RS te p - U pV ol ta g eR e g u l a torC he ck forS a mp l e s: L M 1 5 7 7 , L M 2 5 7 71 FE AT U R E S DE S C R I P T I ONThe LM1577/LM2577 are monolithic integrated2 3 R e qu ir e s Fe w E xte r na lC omp one ntscircuits that provide all of the power and control NP N Ou tp u t S witche s 3.0A, ca n S ta nd off 65 Vfunctions for step-up (boost), flyback, and forward W ideI np u t V ol ta g eR a ng e : 3.5 Vto 40Vconverter switching regulators. The device isavailableinthreedifferent output voltageversions: C u r r e nt- modeOp e r a tion forI mp r ove d12V, 15V, and adjustable.T r a nsie nt R e sp onse , L ineR e g u l a tion, a ndC u r r e nt L imitRequiring a minimum number of externalcomponents,theseregulatorsarecosteffective,and 5 2kH z I nte r na lOscil l a torsimple to use. Listed in this data sheet are a family of S oft- sta r t Fu nction R e du ce s I n- r u sh C u r r e ntstandard inductors and flyback transformers designedDu r ingS ta r t- u pto work with these switching regulators. Ou tp u t S witch P r ote cte d by C u r r e nt L imit,Includedonthechipisa3.0ANPNswitchanditsU nde r - vol ta g eL ockou t, a nd T he r ma lassociatedprotectioncircuitry, consistingof currentS hu tdownand thermal limiting, and undervoltage lockout. Otherfeaturesincludea52kHzfixed-frequencyoscillatorT YP I C ALAP P L I C AT I ONSthat requires no external components, a soft startmodetoreducein-rushcurrent duringstart-up, and S imp l eBoost R e g u l a torcurrent modecontrol for improvedrejectionof input Fl yba ck a nd For wa r d R e g u l a tor svoltage and output load transients. M u l tip l e - ou tp u t R e g u l a torC onne ction Dia g r a msFig u r e1 . 5 - L e a d (S tr a ig ht L e a ds) T O- 2 2 0 (T ) T op Fig u r e2 . 5 - L e a d (Be nt, S ta g g e r e d L e a ds) T O- 2 2 0V ie w (T ) T opV ie wS e eP a cka g eNu mbe rKC S e eP a cka g eNu mbe rNDH 0005 D1Please be aware that an important notice concerning availability, standard warranty, and use in critical applications ofTexas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.2SIMPLE SWITCHER is a registered trademark of Texas Instruments.3All other trademarks are the property of their respective owners.PRODUCTION DATA information is current as of publication date.Copyright 19992013, Texas Instruments IncorporatedProducts conformto specifications per the terms of the TexasInstruments standard warranty. Production processing does notnecessarily include testing of all parameters.L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.com*No Internal Connection*No internal ConnectionFig u r e3. 1 6- L e a d P DI P(N) T opV ie w Fig u r e4. 2 4- L e a d S OI CP a cka g e(M ) T opV ie wS e eP a cka g eNu mbe rNBG001 6G S e eP a cka g eNu mbe rDWFig u r e5 . 5 - L e a d DDP AK/ T O- 2 63 (S ) S FMP a cka g e Fig u r e6. 5 - L e a d DDP AK/ T O- 2 63 (S ) S FMP a cka g eT opV ie w S ideV ie wS e eP a cka g eNu mbe rKT T 0005 BFig u r e7 . 4- L e a d T O- 2 2 0 (K) Bottom V ie wS e eP a cka g eNu mbe rNE B0005 BT yp ica lAp p l ica tionNote : Pin numbers shown are for TO-220 (T) package.These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.2 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013Absol u teM a ximu m R a ting s(1 ) (2 )Supply Voltage 45VOutput Switch Voltage 65VOutput Switch Current(3)6.0APower Dissipation Internally LimitedStorage Temperature Range 65C to +150CLead Temperature Soldering, 10 sec. 260CMaximum Junction Temperature 150CMinimum ESD Rating C = 100 pF, R = 1.5 k 2 kV(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions thedevice is intended to be functional, but device parameter specifications may not be ensured under these conditions. For ensuredspecifications and test conditions, see the Electrical Characteristics.(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability andspecifications.(3) Due to timing considerations of the LM1577/LM2577 current limit circuit, output current cannot be internally limited when theLM1577/LM2577 is used as a step-up regulator. To prevent damage to the switch, its current must be externally limited to 6.0A.However, output current is internally limited when the LM1577/LM2577 is used as a flyback or forward converter regulator in accordanceto the Application Hints.Op e r a tingR a ting sSupply Voltage 3.5V VIN 40VOutput Switch Voltage 0V VSWITCH 60VOutput Switch Current ISWITCH 3.0AJunction Temperature Range LM1577 55C TJ +150CLM2577 40C TJ +125CE l e ctr ica lC ha r a cte r isticsL M 1 5 7 7 - 1 2 , L M 2 5 7 7 - 1 2Specifications with standard type face are for TJ = 25C, and those in bol d typ efa ceapply over full Op e r a tingT e mp e r a tu r eR a ng e . Unless otherwise specified, VIN = 5V, and ISWITCH = 0.S ymbol P a r a me te r C onditions T yp ica l L M 1 5 7 7 - 1 2 L M 2 5 7 7 - 1 2 U nitsL imit(1 ) (2 )L imit(3)(L imits)S YS T E MP AR AM E T E R SCircuit of Figure 29(4)VOUTOutput Voltage VIN = 5V to 10V 12.0 VILOAD = 100 mA to 800 mA(1)11.60/1 1 .40 11.60/1 1 .40 V(min)12.40/1 2 .60 12.40/1 2 .60 V(max)Line Regulation VIN = 3.5V to 10V 20 mVILOAD = 300 mA50/1 00 50/1 00 mV(max)(1)Load Regulation VIN = 5V 20 mVILOAD = 100 mA to 800 mA50/1 00 50/1 00 mV(max)(2) Efficiency VIN = 5V, ILOAD = 800 mA 80 %DE V I C EP AR AM E T E R SISInput Supply Current VFEEDBACK = 14V (Switch Off) 7.5 mA10.0/1 4.0 10.0/1 4.0 mA(max)ISWITCH = 2.0A 25 mAVCOMP = 2.0V (Max Duty Cycle) 50/85 50/85 mA(max)(1) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All limits are used to calculateOutgoing Quality Level, and are 100% production tested.(2) A military RETS electrical test specification is available on request. At the time of printing, the LM1577K-12/883, LM1577K-15/883, andLM1577K-ADJ/883 RETS specifications complied fully with the boldface limits in these columns. The LM1577K-12/883, LM1577K-15/883, and LM1577K-ADJ/883 may also be procured to Standard Military Drawing specifications.(3) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All room temperature limits are100% production tested. All limits at temperature extremes are ensured via correlation using standard Statistical Quality Control (SQC)methods.(4) External components such as the diode, inductor, input and output capacitors can affect switching regulator performance. When theLM1577/LM2577 is used as shown in the Test Circuit, system performance will be as specified by the system parameters.Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 3Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comE l e ctr ica lC ha r a cte r isticsL M 1 5 7 7 - 1 2 , L M 2 5 7 7 - 1 2(continu e d)Specifications with standard type face are for TJ = 25C, and those in bol d typ efa ceapply over full Op e r a tingT e mp e r a tu r eR a ng e . Unless otherwise specified, VIN = 5V, and ISWITCH = 0.S ymbol P a r a me te r C onditions T yp ica l L M 1 5 7 7 - 1 2 L M 2 5 7 7 - 1 2 U nitsL imit(1 ) (2 )L imit(3)(L imits)VUVInput Supply ISWITCH = 100 mA 2.90 VUndervoltage Lockout2.70/2 .65 2.70/2 .65 V(min)3.10/3.1 5 3.10/3.1 5 V(max)fOOscillator Frequency Measured at Switch Pin 52 kHzISWITCH = 100 mA48/42 48/42 kHz(min)56/62 56/62 kHz(max)VREFOutput Reference Measured at Feedback Pin VVoltage VIN = 3.5V to 40V12 11.76/1 1 .64 11.76/1 1 .64 V(min)VCOMP = 1.0V12.24/1 2 .36 12.24/1 2 .36 V(max)Output Reference VIN = 3.5V to 40V 7 mVVoltage Line RegulatorRFBFeedback Pin Input 9.7 kResistanceGMError Amp ICOMP = 30 A to +30 A 370 mhoTransconductance VCOMP = 1.0V225/1 45 225/1 45 mho(min)515/61 5 515/61 5 mho(max)AVOLError Amp VCOMP = 1.1V to 1.9V 80 V/VVoltage Gain RCOMP = 1.0 M(5)50/2 5 50/2 5 V/V(min)Error Amplifier Upper Limit 2.4 VOutput Swing VFEEDBACK = 10.0V2.2/2 .0 2.2/2 .0 V(min)Lower Limit 0.3 VVFEEDBACK = 15.0V0.40/0.5 5 0.40/0.5 5 V(max)Error Amplifier VFEEDBACK = 10.0V to 15.0V 200 AOutput Current VCOMP = 1.0V130/90 130/90 A(min)300/400 300/400 A(max)ISSSoft Start Current VFEEDBACK = 10.0V 5.0 AVCOMP = 0V2.5/1 .5 2.5/1 .5 A(min)7.5/9.5 7.5/9.5 A(max)D Maximum Duty Cycle VCOMP = 1.5V 95 %ISWITCH = 100 mA93/90 93/90 %(min)Switch 12.5 A/VTransconductanceILSwitch Leakage VSWITCH = 65V 10 ACurrent VFEEDBACK = 15V (Switch Off)300/600 300/600 A(max)VSATSwitch Saturation ISWITCH = 2.0A 0.5 VVoltage VCOMP = 2.0V (Max Duty Cycle)0.7/0.9 0.7/0.9 V(max)NPN Switch 4.5 ACurrent Limit3.7/3.0 3.7/3.0 A(min)5.3/6.0 5.3/6.0 A(max)(5) A 1.0 M resistor is connected to the compensation pin (which is the error amplifier's output) to ensure accuracy in measuring AVOL. Inactual applications, this pin's load resistance should be 10 M, resulting in AVOL that is typically twice the ensured minimum limit.4 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013E l e ctr ica lC ha r a cte r isticsL M 1 5 7 7 - 1 5 , L M 2 5 7 7 - 1 5Specifications with standard type face are for TJ = 25C, and those in bol d typ efa ceapply over full Op e r a tingT e mp e r a tu r eR a ng e . Unless otherwise specified, VIN = 5V, and ISWITCH = 0.S ymbol P a r a me te r C onditions T yp ica l L M 1 5 7 7 - 1 5 L M 2 5 7 7 - 1 5 U nitsL imit(1 ) (2 )L imit(3)(L imits)S YS T E MP AR AM E T E R SCircuit of Figure 30(4)VOUTOutput Voltage VIN = 5V to 12V 15.0 VILOAD = 100 mA to 600 mA14.50/1 4.2 5 14.50/1 4.2 5 V(min)(1)15.50/1 5 .7 5 15.50/1 5 .7 5 V(max)Line Regulation VIN = 3.5V to 12V 20 mVILOAD = 300 mA mV(max)50/1 00 50/1 00Load Regulation VIN = 5V 20 mVILOAD = 100 mA to 600 mA mV(max)50/1 00 50/1 00 Efficiency VIN = 5V, ILOAD = 600 mA 80 %DE V I C EP AR AM E T E R SISInput Supply Current VFEEDBACK = 18.0V 7.5 mA(Switch Off)10.0/1 4.0 10.0/1 4.0 mA(max)ISWITCH = 2.0A 25 mAVCOMP = 2.0V50/85 50/85 mA(max)(Max Duty Cycle)VUVInput Supply ISWITCH = 100 mA 2.90 VUndervoltage2.70/2 .65 2.70/2 .65 V(min)Lockout3.10/3.1 5 3.10/3.1 5 V(max)fOOscillator Frequency Measured at Switch Pin 52 kHzISWITCH = 100 mA48/42 48/42 kHz(min)56/62 56/62 kHz(max)VREFOutput Reference Measured at Feedback Pin VVoltage VIN = 3.5V to 40V15 14.70/1 4.5 5 14.70/1 4.5 5 V(min)VCOMP = 1.0V15.30/1 5 .45 15.30/1 5 .45 V(max)Output Reference VIN = 3.5V to 40V 10 mVVoltage Line RegulationRFBFeedback Pin Input 12.2 kVoltage Line RegulatorGMError Amp ICOMP = 30 A to +30 A 300 mhoTransconductance VCOMP = 1.0V170/1 1 0 170/1 1 0 mho(min)420/5 00 420/5 00 mho(max)AVOLError Amp VCOMP = 1.1V to 1.9V 65 V/VVoltage Gain RCOMP = 1.0 M(5)40/2 0 40/2 0 V/V(min)(1) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All limits are used to calculateOutgoing Quality Level, and are 100% production tested.(2) A military RETS electrical test specification is available on request. At the time of printing, the LM1577K-12/883, LM1577K-15/883, andLM1577K-ADJ/883 RETS specifications complied fully with the boldface limits in these columns. The LM1577K-12/883, LM1577K-15/883, and LM1577K-ADJ/883 may also be procured to Standard Military Drawing specifications.(3) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All room temperature limits are100% production tested. All limits at temperature extremes are ensured via correlation using standard Statistical Quality Control (SQC)methods.(4) External components such as the diode, inductor, input and output capacitors can affect switching regulator performance. When theLM1577/LM2577 is used as shown in the Test Circuit, system performance will be as specified by the system parameters.(5) A 1.0 M resistor is connected to the compensation pin (which is the error amplifier's output) to ensure accuracy in measuring AVOL. Inactual applications, this pin's load resistance should be 10 M, resulting in AVOL that is typically twice the ensured minimum limit.Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 5Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comE l e ctr ica lC ha r a cte r isticsL M 1 5 7 7 - 1 5 , L M 2 5 7 7 - 1 5(continu e d)Specifications with standard type face are for TJ = 25C, and those in bol d typ efa ceapply over full Op e r a tingT e mp e r a tu r eR a ng e . Unless otherwise specified, VIN = 5V, and ISWITCH = 0.S ymbol P a r a me te r C onditions T yp ica l L M 1 5 7 7 - 1 5 L M 2 5 7 7 - 1 5 U nitsL imit(1 ) (2 )L imit(3)(L imits)Error Amplifier Upper Limit 2.4 VOutput Swing VFEEDBACK = 12.0V2.2/2 .0 2.2/2 .0 V(min)Lower Limit 0.3 VVFEEDBACK = 18.0V0.4/0.5 5 0.40/0.5 5 V(max)Error Amp VFEEDBACK = 12.0V to 18.0V 200 AOutput Current VCOMP = 1.0V130/90 130/90 A(min)300/400 300/400 A(max)ISSSoft Start Current VFEEDBACK = 12.0V 5.0 AVCOMP = 0V2.5/1 .5 2.5/1 .5 A(min)7.5/9.5 7.5/9.5 A(max)D Maximum Duty VCOMP = 1.5V 95 %Cycle ISWITCH = 100 mA93/90 93/90 %(min)Switch 12.5 A/VTransconductanceILSwitch Leakage VSWITCH = 65V 10 ACurrent VFEEDBACK = 18.0V300/600 300/600 A(max)(Switch Off)VSATSwitch Saturation ISWITCH = 2.0A 0.5 VVoltage VCOMP = 2.0V0.7/0.9 0.7/0.9 V(max)(Max Duty Cycle)NPN Switch VCOMP = 2.0V 4.3 ACurrent Limit3.7/3.0 3.7/3.0 A(min)5.3/6.0 5.3/6.0 A(max)6 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013E l e ctr ica lC ha r a cte r isticsL M 1 5 7 7 - ADJ, L M 2 5 7 7 - ADJSpecifications with standard type face are for TJ = 25C, and those in bol d typ efa ceapply over full Op e r a tingT e mp e r a tu r eR a ng e . Unless otherwise specified, VIN = 5V, VFEEDBACK = VREF, and ISWITCH = 0.S ymbol P a r a me te r C onditions T yp ica l L M 1 5 7 7 - ADJ L M 2 5 7 7 - ADJ U nitsL imit(1 ) (2 )L imit(3)(L imits)S YS T E MP AR AM E T E R SCircuit of Figure 31(4)VOUTOutput Voltage VIN = 5V to 10V 12.0 VILOAD = 100 mA to 800 mA(1)11.60/1 1 .40 11.60/1 1 .40 V(min)12.40/1 2 .60 12.40/1 2 .60 V(max)VOUT/VINLine Regulation VIN = 3.5V to 10V 20 mVILOAD = 300 mA50/1 00 50/1 00 mV(max)VOUT/ILOALoad Regulation VIN = 5V 20 mVDILOAD = 100 mA to 800 mA50/1 00 50/1 00 mV(max) Efficiency VIN = 5V, ILOAD = 800 mA 80 %DE V I C EP AR AM E T E R SISInput Supply Current VFEEDBACK = 1.5V (Switch Off) 7.5 mA10.0/1 4.0 10.0/1 4.0 mA(max)ISWITCH = 2.0A 25 mAVCOMP = 2.0V (Max Duty Cycle)50/85 50/85 mA(max)VUVInput Supply ISWITCH = 100 mA 2.90 VUndervoltage Lockout2.70/2 .65 2.70/2 .65 V(min)3.10/3.1 5 3.10/3.1 5 V(max)fOOscillator Frequency Measured at Switch Pin 52 kHzISWITCH = 100 mA48/42 48/42 kHz(min)56/62 56/62 kHz(max)VREFReference Measured at Feedback Pin VVoltage VIN = 3.5V to 40V1.230 1.214/1 .2 06 1.214/1 .2 06 V(min)VCOMP = 1.0V1.246/1 .2 5 4 1.246/1 .2 5 4 V(max)VREF/VINReference Voltage VIN = 3.5V to 40V 0.5 mVLine RegulationIBError Amp VCOMP = 1.0V 100 nAInput Bias Current300/800 300/800 nA(max)GMError Amp ICOMP = 30 A to +30 A 3700 mhoTransconductance VCOMP = 1.0V2400/1 600 2400/1 600 mho(min)4800/5 800 4800/5 800 mho(max)AVOLError Amp Voltage Gain VCOMP = 1.1V to 1.9V 800 V/VRCOMP = 1.0 M(5)500/2 5 0 500/2 5 0 V/V(min)Error Amplifier Upper Limit 2.4 VOutput Swing VFEEDBACK = 1.0V2.2/2 .0 2.2/2 .0 V(min)Lower Limit 0.3 VVFEEDBACK = 1.5V0.40/0.5 5 0.40/0.5 5 V(max)(1) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All limits are used to calculateOutgoing Quality Level, and are 100% production tested.(2) A military RETS electrical test specification is available on request. At the time of printing, the LM1577K-12/883, LM1577K-15/883, andLM1577K-ADJ/883 RETS specifications complied fully with the boldface limits in these columns. The LM1577K-12/883, LM1577K-15/883, and LM1577K-ADJ/883 may also be procured to Standard Military Drawing specifications.(3) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All room temperature limits are100% production tested. All limits at temperature extremes are ensured via correlation using standard Statistical Quality Control (SQC)methods.(4) External components such as the diode, inductor, input and output capacitors can affect switching regulator performance. When theLM1577/LM2577 is used as shown in the Test Circuit, system performance will be as specified by the system parameters.(5) A 1.0 M resistor is connected to the compensation pin (which is the error amplifier's output) to ensure accuracy in measuring AVOL. Inactual applications, this pin's load resistance should be 10 M, resulting in AVOL that is typically twice the ensured minimum limit.Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 7Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comE l e ctr ica lC ha r a cte r isticsL M 1 5 7 7 - ADJ, L M 2 5 7 7 - ADJ (continu e d)Specifications with standard type face are for TJ = 25C, and those in bol d typ efa ceapply over full Op e r a tingT e mp e r a tu r eR a ng e . Unless otherwise specified, VIN = 5V, VFEEDBACK = VREF, and ISWITCH = 0.S ymbol P a r a me te r C onditions T yp ica l L M 1 5 7 7 - ADJ L M 2 5 7 7 - ADJ U nitsL imit(1 ) (2 )L imit(3)(L imits)Error Amp VFEEDBACK = 1.0V to 1.5V 200 AOutput Current VCOMP = 1.0V130/90 130/90 A(min)300/400 300/400 A(max)ISSSoft Start Current VFEEDBACK = 1.0V 5.0 AVCOMP = 0V2.5/1 .5 2.5/1 .5 A(min)7.5/9.5 7.5/9.5 A(max)D Maximum Duty Cycle VCOMP = 1.5V 95 %ISWITCH = 100 mA93/90 93/90 %(min)ISWITCH/VCSwitch 12.5 A/VOMPTransconductanceILSwitch Leakage VSWITCH = 65V 10 ACurrent VFEEDBACK = 1.5V (Switch Off)300/600 300/600 A(max)VSATSwitch Saturation ISWITCH = 2.0A 0.5 VVoltage VCOMP = 2.0V (Max Duty Cycle)0.7/0.9 0.7/0.9 V(max)NPN Switch VCOMP = 2.0V 4.3 ACurrent Limit3.7/3.0 3.7/3.0 A(min)5.3/6.0 5.3/6.0 A(max)T H E R M ALP AR AM E T E R S(Al lV e r sions)JAThermal Resistance K Package, Junction to Ambient 35JCK Package, Junction to Case 1.5JAT Package, Junction to Ambient 65JCT Package, Junction to Case 2C/WJAN Package, Junction to Ambient(6)85JAM Package, Junction to Ambient(6)100JAS Package, Junction to Ambient(7)37(6) Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads. Additional copperarea will lower thermal resistance further. See thermal model in Switchers Made Simple software.(7) If the DDPAK/TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermallyconnected to the package. Using 0.5 square inches of copper area, JA is 50C/W; with 1 square inch of copper area, JA is 37C/W;and with 1.6 or more square inches of copper area, JA is 32C/W.8 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013T yp ica lP e r for ma nceC ha r a cte r isticsR e fe r e nceV ol ta g e R e fe r e nceV ol ta g evs T e mp e r a tu r e vs T e mp e r a tu r eFig u r e8. Fig u r e9.R e fe r e nceV ol ta g e R e fe r e nceV ol ta g evs T e mp e r a tu r e vs S u p p l y V ol ta g eFig u r e1 0. Fig u r e1 1 . R e fe r e nceV ol ta g e R e fe r e nceV ol ta g evs S u p p l y V ol ta g e vs S u p p l y V ol ta g eFig u r e1 2 . Fig u r e1 3.Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 9Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comT yp ica lP e r for ma nceC ha r a cte r istics (continu e d)E r r orAmpT r a nscondu cta nce E r r orAmpT r a nscondu cta ncevs T e mp e r a tu r e vs T e mp e r a tu r eFig u r e1 4. Fig u r e1 5 .E r r orAmpV ol ta g eGa inE r r orAmpT r a nscondu cta nce vsvs T e mp e r a tu r e T e mp e r a tu r eFig u r e1 6. Fig u r e1 7 .E r r orAmpV ol ta g e E r r orAmpV ol ta g eGa in Ga invs vsT e mp e r a tu r e T e mp e r a tu r eFig u r e1 8. Fig u r e1 9.10 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013T yp ica lP e r for ma nceC ha r a cte r istics (continu e d)Qu ie sce nt C u r r e nt Qu ie sce nt C u r r e ntvs T e mp e r a tu r e vs S witch C u r r e ntFig u r e2 0. Fig u r e2 1 .C u r r e nt L imit R e sp onseT imeC u r r e nt L imit vsvs T e mp e r a tu r e Ove r dr iveFig u r e2 2 . Fig u r e2 3.S witch S a tu r a tion V ol ta g e S witch T r a nscondu cta ncevs S witch C u r r e nt vs T e mp e r a tu r eFig u r e2 4. Fig u r e2 5 .Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 11Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comT yp ica lP e r for ma nceC ha r a cte r istics (continu e d)Fe e dba ck P in Bia sC u r r e ntvs Oscil l a torFr e qu e ncyT e mp e r a tu r e vs T e mp e r a tu r eFig u r e2 6. Fig u r e2 7 .M a ximu m P owe rDissip a tion(DDP AK/ T O- 2 63)(1 )Fig u r e2 8.(1) If the DDPAK/TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermallyconnected to the package. Using 0.5 square inches of copper area, JA is 50C/W; with 1 square inch of copper area, JA is 37C/W;and with 1.6 or more square inches of copper area, JA is 32C/W.12 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013L M 1 5 7 7 - 1 2 , L M 2 5 7 7 - 1 2T E S TC I R C U I TL = 415-0930 (AIE)D = any manufacturerCOUT = Sprague Type 673DElectrolytic 680 F, 20VNote : Pin numbers shown are for TO-220 (T) packageFig u r e2 9. C ir cu it U se d to S p e cify S yste m P a r a me te r s for1 2 VV e r sionsL M 1 5 7 7 - 1 5 , L M 2 5 7 7 - 1 5T e st C ir cu itL = 415-0930 (AIE)D = any manufacturerCOUT = Sprague Type 673DElectrolytic 680 F, 20VNote : Pin numbers shown are for TO-220 (T) packageFig u r e30. C ir cu it U se d to S p e cify S yste m P a r a me te r s for1 5 VV e r sionsCopyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 13Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comL M 1 5 7 7 - ADJ, L M 2 5 7 7 - ADJ T e st C ir cu itL = 415-0930 (AIE)D = any manufacturerCOUT = Sprague Type 673DElectrolytic 680 F, 20VR1 = 48.7k in series with 511 (1%)R2 = 5.62k (1%)Note : Pin numbers shown are for TO-220 (T) packageFig u r e31 . C ir cu it U se d to S p e cify S yste m P a r a me te r s forADJ V e r sionsAp p l ica tion H intsNote : Pin numbers shown are for TO-220 (T) package*Resistors are internal to LM1577/LM2577 for 12V and 15V versions.Fig u r e32 . L M 1 5 7 7 / L M 2 5 7 7Bl ock Dia g r a m a nd Boost R e g u l a torAp p l ica tion14 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013S T E P - U P(BOOS T ) R E GU L AT ORFigure 32 shows the LM1577-ADJ/LM2577-ADJ used as a Step-Up Regulator. This is a switching regulator usedfor producing an output voltage greater than the input supply voltage. The LM1577-12/LM2577-12 and LM1577-15/LM2577-15canalsobeusedfor step-upregulatorswith12Vor 15Voutputs(respectively), bytyingthefeedback pin directly to the regulator output.Abasicexplanationofhowitworksisasfollows.TheLM1577/LM2577turnsitsoutputswitchonandoffatafrequencyof 52kHz, andthiscreatesenergyintheinductor(L). WhentheNPNswitchturnson, theinductorcurrent charges up at a rate of VIN/L, storing current in the inductor. When the switch turns off, the lower end ofthe inductor flies above VIN, discharging its current through diode (D) into the output capacitor (COUT) at a rate of(VOUT VIN)/L. Thus, energy stored in the inductor during the switch on time is transferred to the output duringtheswitchoff time. Theoutput voltageiscontrolledbytheamount of energytransferredwhich, inturn, iscontrolled by modulating the peak inductor current. This is done by feeding back a portion of the output voltageto the error amp, which amplifies the difference between the feedback voltage and a 1.230V reference. The erroramp output voltage is compared to a voltage proportionalto the switch current (i.e., inductor current during theswitch on time).Thecomparatorterminatestheswitchontimewhenthetwovoltagesareequal, therebycontrollingthepeakswitch current to maintain a constant output voltage.Voltageandcurrent waveformsfor thiscircuit areshowninFigure33, andformulasfor calculatingthemaregiven in Table 1.Fig u r e33. S te p - U pR e g u l a torW a ve for msT a bl e1 . S te p - U pR e g u l a torFor mu l a s(1 )Duty Cycle DAverage Inductor CurrentIIND(AVE)Inductor Current RippleIINDPeak Inductor CurrentIIND(PK)Peak Switch CurrentISW(PK)Switch Voltage When Off VSW(OFF)VOUT + VFDiode Reverse Voltage VRVOUT VSATAverage Diode Current ID(AVE)ILOADPeak Diode CurrentID(PK)Power Dissipation of LM1577/2577PD(1) VF = Forward Biased Diode VoltageILOAD = Output Load CurrentCopyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 15Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comS T E P - U PR E GU L AT ORDE S I GN P R OC E DU R EThefollowingdesignprocedurecanbeusedtoselect theappropriateexternal componentsfor thecircuit inFigure 32, based on these system requirements.Give n: VIN(min) = Minimum input supply voltage VOUT = Regulated output voltage ILOAD(max) = Maximum output load current Beforeproceedinganyfurther, determineif theLM1577/LM2577canprovidethesevaluesof VOUTandILOAD(max) when operating with the minimum value of VIN. The upper limits for VOUT and ILOAD(max) are given bythe following equations.where VOUT 60V VOUT 10 VIN(min)(3)These limits must be greater than or equal to the values specified in this application.1 . I ndu ctorS e l e ction (L )A. Voltage Options:1. For1 2 Vor1 5 Vou tp u tFr om Fig u r e34 (for1 2 Vou tp u t) orFig u r e35(for1 5 Vou tp u t), ide ntify indu ctorcodefor regionindicated by VIN(min) and ILOAD(max). The shaded region indicates conditions for which the LM1577/LM2577output switch would be operating beyond its switch current rating. The minimum operating voltage for theLM1577/LM2577 is 3.5V.From here, proceed to step C.2. ForAdju sta bl eve r sionP r e l imina r y ca l cu l a tions:The inductor selection is based on the calculation of the following three parameters:D(max), the maximum switch duty cycle (0 D 0.9):(4)where VF = 0.5V for Schottky diodes and 0.8V for fast recovery diodes (typically);E T, the product of volts time that charges the inductor:(5)IIND,DC, the average inductor current under full load;(6)B. Identify Inductor Value:1. From Figure 36, identify the inductor code for the region indicated by the intersection of ET and IIND,DC.This code gives the inductor value in microhenries. The L or H prefix signifies whether the inductor is ratedfor a maximum ET of 90 Vs (L) or 250 Vs (H).2. If D < 0.85, go on to step C. If D 0.85, then calculate the minimum inductance needed to ensure theswitching regulator's stability:(7)If LMIN is smaller than the inductor value found in step B1, go on to step C. Otherwise, the inductor value found instep B1 is too low; an appropriate inductor code should be obtained from the graph as follows:1. Find the lowest value inductor that is greater than LMIN.16 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 20132. Find where ET intersects this inductor value to determine if it has an L or H prefix. If ET intersects both the Land H regions, select the inductor with an H prefix.Fig u r e34. L M 2 5 7 7 - 1 2I ndu ctorS e l e ction Gu ideFig u r e35 . L M 2 5 7 7 - 1 5I ndu ctorS e l e ction Gu ideCopyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 17Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comNote : These charts assume that the inductor ripple current is approximately 20% to 30% of the average inductorcurrent (when the regulator is under full load). Greater ripple current causes higher peak switch currents and greateroutput ripple voltage; lower ripple current is achieved with larger-value inductors. The factor of 20 to 30% is chosen asa convenient balance between the two extremes.Fig u r e36. L M 1 5 7 7 - ADJ/ L M 2 5 7 7 - ADJ I ndu ctorS e l e ction Gr a p hC . Select an inductor from Table 2 which cross-references the inductor codes to the part numbers of threedifferent manufacturers. Complete specifications for these inductors are available from the respectivemanufacturers. The inductors listed in this table have the following characteristics: AIE: ferrite, pot-core inductors; Benefits of this type are low electro-magnetic interference (EMI), smallphysical size, and very low power dissipation (core loss). Be careful not to operate these inductors toofar beyond their maximum ratings for ET and peak current, as this will saturate the core. Pulse: powdered iron, toroid core inductors; Benefits are low EMI and ability to withstand ET and peakcurrent above rated value better than ferrite cores. Renco: ferrite, bobbin-core inductors; Benefits are low cost and best ability to withstand ET and peakcurrent above rated value. Be aware that these inductors generate more EMI than the other types, andthis may interfere with signals sensitive to noise.18 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013T a bl e2 . T a bl eof S ta nda r dize d I ndu ctor s a ndM a nu fa ctu r e r 's P a r t Nu mbe r s(1 )I ndu ctor M a nu fa ctu r e r 's P a r t Nu mbe rC ode S chott P u l se R e ncoL47 67126980 PE - 53112 RL2442L68 67126990 PE - 92114 RL2443L100 67127000 PE - 92108 RL2444L150 67127010 PE - 53113 RL1954L220 67127020 PE - 52626 RL1953L330 67127030 PE - 52627 RL1952L470 67127040 PE - 53114 RL1951L680 67127050 PE - 52629 RL1950H150 67127060 PE - 53115 RL2445H220 67127070 PE - 53116 RL2446H330 67127080 PE - 53117 RL2447H470 67127090 PE - 53118 RL1961H680 67127100 PE - 53119 RL1960H1000 67127110 PE - 53120 RL1959H1500 67127120 PE - 53121 RL1958H2200 67127130 PE - 53122 RL2448(1) S chott C or p ., (612) 475-11731000 Parkers Lake Rd., Wayzata, MN 55391P u l seE ng ine e r ing , (619) 268-2400P.O. Box 12235, San Diego, CA 92112R e nco E l e ctr onics I nc., (516) 586-556660 Jeffryn Blvd. East, Deer Park, NY 117292 . C omp e nsa tion Ne twor k (RC, CC) a nd Ou tp u t C a p a citor(COU T) S e l e ctionRCandCCformapole-zerocompensationnetworkthat stabilizestheregulator. Thevaluesof RCandCCaremainly dependant on the regulator voltage gain, ILOAD(max), L and COUT. The following procedure calculates valuesfor RC, CC, and COUT that ensure regulator stability. Be aware that this procedure doesn't necessarily result in RCandCCthat provideoptimumcompensation. Inorder toensureoptimumcompensation, oneof thestandardproceduresfor testingloopstabilitymust beused, suchasmeasuringVOUTtransient responsewhenpulsingILOAD (see Figure 39).A. First, calculate the maximum value for RC.(8)Select a resistor less than or equal to this value, and it should also be no greater than 3 k.B. Calculate the minimum value for COUT using the following two equations.(9)The larger of these two values is the minimum value that ensures stability.C. Calculate the minimum value of CC .(10)Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 19Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comThe compensation capacitor is also part of the soft start circuitry. When power to the regulator is turned on, theswitchdutycycleisallowedtoriseat aratecontrolledbythiscapacitor(withnocontrol onthedutycycle, itwould immediately rise to 90%, drawing huge currents from the input power supply). In order to operate properly,the soft start circuit requires CC 0.22 F.Thevalueof theoutput filter capacitor isnormallylargeenoughtorequiretheuseof aluminumelectrolyticcapacitors. Table 3 lists several different types that are recommended for switching regulators, and the followingparameters are used to select the proper capacitor.WorkingVoltage(WVDC): Chooseacapacitor withaworkingvoltageat least 20%higher thantheregulatoroutput voltage.RippleCurrent: ThisisthemaximumRMSvalueof current that chargesthecapacitor duringeachswitchingcycle. For step-up and flyback regulators, the formula for ripple current is(11)Choose a capacitor that is rated at least 50% higher than this value at 52 kHz.EquivalentSeriesResistance(ESR):Thisistheprimarycauseofoutputripplevoltage,anditalsoaffectsthevalues of RC and CC needed to stabilize the regulator. As a result, the preceding calculations for CC and RC areonly valid if ESR doesn't exceed the maximum value specified by the following equations.(12)Select a capacitor with ESR, at 52 kHz, that is less than or equal to the lower value calculated. Most electrolyticcapacitorsspecifyESRat 120Hzwhichis15%to30%higher thanat 52kHz. Also, beawarethat ESRincreases by a factor of 2 when operating at 20C.Ingeneral,lowvaluesofESRareachievedbyusinglargevaluecapacitors(C 470 F),andcapacitorswithhigh WVDC, or by paralleling smaller-value capacitors.3. Ou tp u t V ol ta g eS e l e ction (R 1a nd R 2 )This section is for applications using the LM1577-ADJ/LM2577-ADJ. Skip this section if the LM1577-12/LM2577-12 or LM1577-15/LM2577-15 is being used.With the LM1577-ADJ/LM2577-ADJ, the output voltage is given byVOUT = 1.23V (1 + R1/R2) (13)Resistors R1 and R2 divide the output down so it can be compared with the LM1577-ADJ/LM2577-ADJ internal1.23V reference. For a given desired output voltage VOUT, select R1 and R2 so that(14)4. I np u t C a p a citorS e l e ction (CI N)Theswitchingactioninthestep-upregulator causesatriangular ripplecurrent tobedrawnfromthesupplysource. This in turn causes noise to appear on the supply voltage. For proper operation of the LM1577, the inputvoltage should be decoupled. Bypassing the Input Voltage pin directly to ground with a good quality, low ESR,0.1 F capacitor (leads as short as possible) is normally sufficient.20 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013T a bl e3. Al u minu m E l e ctr ol ytic C a p a citor sR e comme nde d forS witchingR e g u l a tor sC or ne l lDu bl ie rTypes 239, 250, 251, UFT, 300, or 350P.O. Box 128, Pickens, SC 29671(803) 878-6311Nichicon Types PF, PX, or PZ927 East Parkway,Schaumburg, IL 60173(708) 843-7500S p r a g u eTypes 672D, 673D, or 674DBox 1, Sprague Road,Lansing, NC 28643(919) 384-2551U nite d C he mi- C on Types LX, SXF, or SXJ9801 West Higgins Road,Rosemont, IL 60018(708) 696-2000If the LM1577 is located far from the supply source filter capacitors, an additional large electrolytic capacitor (e.g.47 F) is often required.5 . DiodeS e l e ction (D)Theswitchingdiodeusedintheboost regulator must withstandareversevoltageequal tothecircuit outputvoltage, andmust conduct thepeakoutput current of theLM2577. Asuitablediodemust haveaminimumreversebreakdownvoltagegreaterthanthecircuit output voltage, andshouldberatedforaverageandpeakcurrent greater than ILOAD(max) and ID(PK). Schottky barrier diodes are often favored for use in switching regulators.Theirlowforwardvoltagedropallowshigherregulatorefficiencythanifa(lessexpensive)fastrecoverydiodewas used. See Table 4 for recommended part numbers and voltage ratings of 1A and 3A diodes.T a bl e4. DiodeS e l e ction C ha r tVOU TS chottky Fa st R e cove r y(ma x) 1 A 3A 1 A 3A20V 1N5817 1N5820MBR120P MBR320P1N5818 1N582130V MBR130P MBR330P11DQ03 31DQ031N5819 1N582240V MBR140P MBR340P11DQ04 31DQ04MBR150 MBR350 1N493350V 11DQ05 31DQ05 MUR1051N4934 MR851100V HER102 30DL1MUR110 MR83110DL1 HER302BOOS TR E GU L AT ORC I R C U I TE XAM P L EBy adding a few external components (as shown in Figure 37), the LM2577 can be used to produce a regulatedoutput voltagethat isgreaterthantheappliedinput voltage. Typical performanceof thisregulatorisshowninFigure38andFigure39. Theswitchingwaveformsobservedduringtheoperationof thiscircuit areshowninFigure 40.Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 21Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comNote : Pin numbers shown are for TO-220 (T) package.Fig u r e37 . S te p - u pR e g u l a torDe l ive r s 1 2 Vfr om a5 VI np u tFig u r e38. L ineR e g u l a tion (T yp ica l ) of S te p - U pR e g u l a torof Fig u r e37A: Output Voltage Change, 100 mV/div. (AC-coupled)B: Load current, 0.2 A/divH or izonta l : 5ms/ divFig u r e39. L oa d T r a nsie nt R e sp onseof S te p - U pR e g u l a torof Fig u r e3722 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013A: Switch pin voltage, 10 V/divB: Switch pin current, 2 A/divC: Inductor current, 2 A/divD: Output ripple voltage, 100 mV/div (AC-coupled)H or izonta l : 5 s/ divFig u r e40. S witchingW a ve for ms of S te p - U pR e g u l a torof Fig u r e37FL YBAC K R E GU L AT ORA Flyback regulator can produce single or multiple output voltages that are lower or greater than the input supplyvoltage. Figure 42 shows the LM1577/LM2577 used as a flyback regulator with positive and negative regulatedoutputs. Its operation is similar to a step-up regulator, except the output switch contols the primary current of aflyback transformer. Note that the primary and secondary windings are out of phase, so no current flows throughsecondarywhencurrent flowsthroughtheprimary. Thisallowstheprimarytochargeupthetransformercorewhen the switch is on. When the switch turns off, the core discharges by sending current through the secondary,andthisproducesvoltageat theoutputs. Theoutput voltagesarecontrolledbyadjustingthepeakprimarycurrent, as described in the STEP-UP (BOOST) REGULATOR section.Voltageandcurrent waveformsfor thiscircuit areshowninFigure41, andformulasfor calculatingthemaregiven in Table 5.FL YBAC K R E GU L AT ORDE S I GN P R OC E DU R E1. Transformer SelectionA family of standardized flyback transformers is available for creating flyback regulators that produce dual outputvoltages, from10Vto15V, asshowninFigure42. Table6liststhesetransformerswiththeinput voltage,output voltages and maximum load current they are designed for.2. Compensation Network (CC, RC) andOutput Capacitor (COUT) SelectionAs explained in the Step-Up Regulator Design Procedure, CC, RC and COUT must be selected as a group. Thefollowingprocedureisforadual output flybackregulatorwithequal turnsratiosforeachsecondary(i.e., bothoutput voltages have the same magnitude). The equations can be used for a single output regulator by changingILOAD(max) to ILOAD(max) in the following equations.A. Fir st, ca l cu l a tethema ximu m va l u eforRC.Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 23Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.com(15)Where ILOAD(max) isthesumoftheloadcurrent(magnitude)requiredfrombothoutputs.Selectaresistorlessthan or equal to this value, and no greater than 3 k.B. C a l cu l a tetheminimu m va l u efor COU T(sum of COUT at both outputs) using the following two equations.(16)The larger of these two values must be used to ensure regulator stability.Fig u r e41 . Fl yba ck R e g u l a torW a ve for msT1 = Pulse Engineering, PE-65300D1, D2 = 1N5821Fig u r e42 . L M 1 5 7 7 - ADJ/ L M 2 5 7 7 - ADJ Fl yba ck R e g u l a torwith Ou tp u tsT a bl e5 . Fl yba ck R e g u l a torFor mu l a sDuty Cycle D(17)Primary Current VariationIP(18)24 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013T a bl e5 . Fl yba ck R e g u l a torFor mu l a s (continu e d)Peak Primary CurrentIP(PK)(19)Switch Voltage when OffVSW(OFF)(20)Diode Reverse Voltage VRVOUT+N (VIN VSAT)Average Diode Current ID(AVE)ILOADPeak Diode CurrentID(PK)(21)Short Circuit Diode Current(22)Power Dissipation of LM1577/LM2577PD(23)C. Calculate the minimum value of CC(24)D. Calculate the maximum ESR of the +VOUT and VOUT output capacitors in parallel.(25)This formula can also be used to calculate the maximum ESR of a single output regulator.At this point, refer to this same section in the STEP-UP REGULATOR DESIGN PROCEDURE section for moreinformation regarding the selection of COUT.3. Ou tp u t V ol ta g eS e l e ctionThis section is for applications using the LM1577-ADJ/LM2577-ADJ. Skip this section if the LM1577-12/LM2577-12 or LM1577-15/LM2577-15 is being used.With the LM1577-ADJ/LM2577-ADJ, the output voltage is given byVOUT = 1.23V (1 + R1/R2) (26)Resistors R1 and R2 divide the output voltage down so it can be compared with the LM1577-ADJ/LM2577-ADJinternal 1.23V reference. For a desired output voltage VOUT, select R1 and R2 so that(27)4. DiodeS e l e ctionThe switching diode in a flyback converter must withstand the reverse voltage specified by the followingequation.(28)A suitable diode must have a reverse voltage rating greater than this. In addition it must be rated for more thanthe average and peak diode currents listed in Table 5.5 . I np u t C a p a citorS e l e ctionCopyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 25Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comThe primary of a flyback transformer draws discontinuous pulses of current from the input supply. As a result, aflybackregulatorgeneratesmorenoiseattheinputsupplythanastep-upregulator,andthisrequiresalargerbypass capacitor to decouple the LM1577/LM2577 VIN pin from this noise. For most applications, a low ESR, 1.0F cap will be sufficient, if it is connected very close to the VIN and Ground pins.T r a nsfor me r I np u t Du a l M a ximu mT yp e V ol ta g e Ou tp u t Ou tp u tV ol ta g e C u r r e ntLP = 100 H 5V 10V 325 mA1 N = 1 5V 12V 275 mA5V 15V 225 mA10V 10V 700 mA10V 12V 575 mA2 LP = 200 H 10V 15V 500 mAN = 0.5 12V 10V 800 mA12V 12V 700 mA12V 15V 575 mA3 LP = 250 H 15V 10V 900 mAN = 0.5 15V 12V 825 mA15V 15V 700 mAT a bl e6. Fl yba ck T r a nsfor me rS e l e ction Gu ideT r a nsfor me r M a nu fa ctu r e r s' P a r t Nu mbe r sT yp e AI E P u l se R e nco1 326-0637 PE-65300 RL-25802 330-0202 PE-65301 RL-25813 330-0203 PE-65302 RL-2582Inadditiontothisbypasscap, alarger capacitor (47 F) shouldbeusedwheretheflybacktransformerconnectstotheinputsupply.Thiswill attenuatenoisewhichmayinterferewithothercircuitsconnectedtothesame input supply voltage.6. S nu bbe rC ir cu itA snubber circuit is required when operating from input voltages greater than 10V, or when using a transformerwith LP 200 H. This circuit clamps a voltage spike from the transformer primary that occurs immediately aftertheoutput switchturnsoff. Without it, theswitchvoltagemayexceedthe65Vmaximumrating. AsshowninFigure43, thesnubberconsistsof afast recoverydiode, andaparallel RC. TheRCvaluesareselectedforswitch clamp voltage (VCLAMP) that is 5V to 10V greater than VSW(OFF). Use the following equations to calculate Rand C;(29)Power dissipation (and power rating) of the resistor is;(30)The fast recovery diode must have a reverse voltage rating greater than VCLAMP.26 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013Fig u r e43. S nu bbe rC ir cu itFL YBAC K R E GU L AT ORC I R C U I TE XAM P L EThecircuitofFigure44 produces15V(at225mAeach)fromasingle5Vinput.Theoutputregulationofthiscircuit isshowninFigure45andFigure47, whiletheloadtransient responseisshowninFigure46andFigure 48. Switching waveforms seen in this circuit are shown in Figure 49.T1 = Pulse Engineering, PE-65300D1, D2 = 1N5821Fig u r e44. Fl yba ck R e g u l a torE a sil y P r ovide s Du a lOu tp u tsFig u r e45 . L ineR e g u l a tion (T yp ica l ) of Fl yba ckR e g u l a torof Fig u r e44, +1 5 VOu tp u tCopyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 27Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comA: Output Voltage Change, 100 mV/divB: Output Current, 100 mA/divH or izonta l : 1 0 ms/ divFig u r e46. L oa d T r a nsie nt R e sp onseof Fl yba ckR e g u l a torof Fig u r e44, +1 5 VOu tp u tFig u r e47 . L ineR e g u l a tion (T yp ica l ) of Fl yba ckR e g u l a torof Fig u r e44, 1 5 VOu tp u t28 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7www.ti.com SNOS658D JUNE 1999REVISED APRIL 2013A: Output Voltage Change, 100 mV/divB: Output Current, 100 mA/divH or izonta l : 1 0 ms/ divFig u r e48. L oa d T r a nsie nt R e sp onseof Fl yba ckR e g u l a torof Fig u r e44, 1 5 VOu tp u tA: Switch pin voltage, 20 V/divB: Primary current, 2 A/divC: +15V Secondary current, 1 A/divD: +15V Output ripple voltage, 100 mV/divH or izonta l : 5 s/ divFig u r e49. S witchingW a ve for ms of Fl yba ck R e g u l a torof Fig u r e44, E a ch Ou tp u t L oa de d with 60Copyright 19992013, Texas Instruments Incorporated Submit Documentation Feedback 29Product Folder Links: LM1577 LM2577L M 1 5 7 7 , L M 2 5 7 7SNOS658D JUNE 1999REVISED APRIL 2013 www.ti.comR E V I S I ON H I S T OR YC ha ng e s fr om R e vision C(Ap r il2 01 3) to R e vision D P a g e Changed layout of National Data Sheet to TI format .......................................................................................................... 2930 Submit Documentation Feedback Copyright 19992013, Texas Instruments IncorporatedProduct Folder Links: LM1577 LM2577PACKAGE OPTION ADDENDUMwww.ti.com 16-Jun-2015Addendum-Page 1PACKAGING INFORMATIONOrderable Device Status(1)Package Type PackageDrawingPins PackageQtyEco Plan(2)Lead/Ball Finish(6)MSL Peak Temp(3)Op Temp (C) Device Marking(4/5)SamplesLM2577M-ADJ/NOPB ACTIVE SOIC DW 24 30 Green (RoHS& no Sb/Br)CU SN Level-3-260C-168 HR -40 to 125 LM2577M-ADJ P+LM2577N-ADJ/NOPB ACTIVE PDIP NBG 16 20 Green (RoHS& no Sb/Br)CU SN Level-1-NA-UNLIM -40 to 125 LM2577N-ADJP+LM2577S-12/NOPB ACTIVE DDPAK/TO-263KTT 5 45 Pb-Free (RoHSExempt)CU SN Level-3-245C-168 HR -40 to 125 LM2577S-12 P+LM2577S-ADJ NRND DDPAK/TO-263KTT 5 45 TBD Call TI Call TI -40 to 125 LM2577S-ADJ P+LM2577S-ADJ/NOPB ACTIVE DDPAK/TO-263KTT 5 45 Pb-Free (RoHSExempt)CU SN Level-3-245C-168 HR -40 to 125 LM2577S-ADJ P+LM2577SX-12/NOPB ACTIVE DDPAK/TO-263KTT 5 500 Pb-Free (RoHSExempt)CU SN Level-3-245C-168 HR -40 to 125 LM2577S-12 P+LM2577SX-ADJ NRND DDPAK/TO-263KTT 5 500 TBD Call TI Call TI -40 to 125 LM2577S-ADJ P+LM2577SX-ADJ/NOPB ACTIVE DDPAK/TO-263KTT 5 500 Pb-Free (RoHSExempt)CU SN Level-3-245C-168 HR -40 to 125 LM2577S-ADJ P+LM2577T-12 NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2577T-12P+LM2577T-12/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2577T-12P+LM2577T-12/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS& no Sb/Br)CU SN Level-1-NA-UNLIM LM2577T-12P+LM2577T-12/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS& no Sb/Br)CU SN Level-1-NA-UNLIM -40 to 125 LM2577T-12P+LM2577T-15 NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2577T-15P+LM2577T-15/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2577T-15P+LM2577T-15/NOPB ACTIVE TO-220 KC 5 45 Green (RoHS& no Sb/Br)CU SN Level-1-NA-UNLIM -40 to 125 LM2577T-15P+LM2577T-ADJ NRND TO-220 KC 5 45 TBD Call TI Call TI -40 to 125 LM2577T-ADJP+LM2577T-ADJ/LB02 NRND TO-220 NEB 5 45 TBD Call TI Call TI LM2577TPACKAGE OPTION ADDENDUMwww.ti.com 16-Jun-2015Addendum-Page 2Orderable Device Status(1)Package Type PackageDrawingPins PackageQtyEco Plan(2)Lead/Ball Finish(6)MSL Peak Temp(3)Op Temp (C) Device Marking(4/5)Samples-ADJP+LM2577T-ADJ/LB03 NRND TO-220 NDH 5 45 TBD Call TI Call TI LM2577T-ADJP+LM2577T-ADJ/LF03 ACTIVE TO-220 NDH 5 45 Green (RoHS& no Sb/Br)CU SN Level-1-NA-UNLIM LM2577T-ADJP+LM2577T-ADJ/NOPB ACTIVE TO-220 KC 5 45 Pb-Free (RoHSExempt)CU SN Level-1-NA-UNLIM -40 to 125 LM2577T-ADJP+ (1) The marketing status values are defined as follows:ACTIVE: Product device recommended for new designs.LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.PREVIEW: Device has been announced but is not in production. Samples may or may not be available.OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availabilityinformation and additional product content details.TBD:The Pb-Free/Green conversion plan has not been defined.Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement thatlead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-baseddie adhesive used betweenthe die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br)and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weightin homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuationof the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finishvalue exceeds the maximum column width.PACKAGE OPTION ADDENDUMwww.ti.com 16-Jun-2015Addendum-Page 3 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on informationprovided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. 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TAPE AND REEL INFORMATION*All dimensions are nominalDevice PackageTypePackageDrawingPins SPQ ReelDiameter(mm)ReelWidthW1 (mm)A0(mm)B0(mm)K0(mm)P1(mm)W(mm)Pin1QuadrantLM2577SX-12/NOPB DDPAK/TO-263KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2LM2577SX-ADJ DDPAK/TO-263KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2LM2577SX-ADJ/NOPB DDPAK/TO-263KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2PACKAGE MATERIALS INFORMATIONwww.ti.com 23-Sep-2013Pack Materials-Page 1*All dimensions are nominalDevice Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)LM2577SX-12/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0LM2577SX-ADJ DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0LM2577SX-ADJ/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0PACKAGE MATERIALS INFORMATIONwww.ti.com 23-Sep-2013Pack Materials-Page 2MECHANICAL DATANDH0005Dwww.ti.comMECHANICAL DATANBG0016Gwww.ti.comMECHANICAL DATAKTT0005Bwww.ti.comBOTTOM SIDE OF PACKAGETS5B (Rev D)MECHANICAL DATANEB0005Bwww.ti.comIMPORTANT NOTICETexas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and otherchanges to its semiconductor products and services per J ESD46, latest issue, and to discontinue any product or service per J ESD48, latestissue. 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