This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
This device includes two specialized N−Channel MOSFETs in adual PQFN package. The switch node has been internally connected toenable easy placement and routing of synchronous buck converters.The control MOSFET (Q1) and synchronous SyncFET™ (Q2) havebeen designed to provide optimal power efficiency.
FeaturesQ1: N−Channel• Max rDS(on) = 8 m� at VGS = 10 V, ID = 13 A
• Max rDS(on) = 11 m� at VGS = 4.5 V, ID = 11 AQ2: N−Channel• Max rDS(on) = 2.6 m� at VGS = 10 V, ID = 23 A
VGS = 0 V, IS = 13 A (Note 2)VGS = 0 V, IS = 23 A (Note 2)
Q1Q2
0.80.8
1.21.2
V
trr Reverse Recovery Time Q1IF = 13 A, di/dt = 100 A/�s Q2IF = 23 A, di/dt = 300 A/�s
Q1Q2
2532
4051
ns
Qrr Reverse Recovery Charge Q1Q2
939
1862
nC
1. R�JA is determined with the device mounted on a 1 in2 pad 2 oz copper pad on a 1.5 x 1.5 in. board of FR−4 material. R�JC is guaranteedby design while R�CA is determined by the user’s board design.
a. 57 °C/W when mounted on a 1 in2 pad of 2 oz copper
c. 125 °C/W when mounted on a minimum pad of 2 oz copper
b. 50 °C/W when mounted on a 1 in2 pad of 2 oz copper
d. 120 °C/W when mounted on a minimum pad of 2 oz copper
2. Pulse Test: Pulse Width < 300 �s, Duty cycle < 2.0%.3. As an N−ch device, the negative Vgs rating is for low duty cycle pulse ocurrence only. No continuous rating is implied.4. EAS of 40 mJ is based on starting TJ = 25°C; N−ch: L = 1 mH, IAS = 9 A, VDD = 27 V, VGS = 10 V. 100% test at L = 0.3 mH, IAS = 14 A.5. EAS of 60 mJ is based on starting TJ = 25°C; N−ch: L = 1 mH, IAS = 11 A, VDD = 27 V, VGS = 10 V. 100% test at L = 0.3 mH, IAS = 18 A.
NOTES:DUTY FACTOR: D = t1/t2PEAK TJ = PDM x Z�JA x R�JA + TA
C/W
(Note 1c)
SyncFET Schottky Body Diode CharacteristicsON Semiconductor’s SyncFET process embeds a
Schottky diode in parallel with PowerTrench MOSFET.This diode exhibits similar characteristics to a discreteexternal Schottky diode in parallel with a MOSFET.Figure 27 shows the reverse recovery characteristic of theFDMS3604S.
Schottky barrier diodes exhibit significant leakage at hightemperature and high reverse voltage. This will increase thepower in the device.
Figure 27. FDMS3604S SyncFET Body Diode Reverse Recovery Characteristics
Figure 28. SyncFET Body Diode Reverse Leakage versus Drain−source Voltage
Switch Node Ringing SuppressionON Semiconductor’s Power Stage products incorporate a
proprietary design* that minimizes the peak overshoot,ringing voltage on the switch node (PHASE) without theneed of any external snubbing components in a buck
converter. As shown in the Figure 29, the Power Stagesolution rings significantly less than competitor solutionsunder the same set of test conditions.
Figure 29. Power Stage Phase Node Rising Edge, High Turn On
Power Stage Device Competitorrs Solution
*Patent Pending
Figure 30. Shows the Power Stage in a Buck Converter Topology
Recommended PCB Layout GuidelinesAs a PCB designer, it is necessary to address critical issues
in layout to minimize losses and optimize the performanceof the power train. Power Stage is a high power densitysolution and all high current flow paths, such as VIN (D1),PHASE (S1/D2) and GND (S2), should be short and wide
for better and stable current flow, heat radiation and systemperformance. A recommended layout procedure isdiscussed below to maximize the electrical and thermalperformance of the part.
Figure 31. Recommended PCB Layout
Following is a guideline, not a requirement which the PCB designer should consider:1. Input ceramic bypass capacitors C1 and C2 must
be placed close to the D1 and S2 pins of PowerStage to help reduce parasitic inductance and HighFrequency conduction loss induced by switchingoperation. C1 and C2 show the bypass capacitorsplaced close to the part between D1 and S2. Inputcapacitors should be connected in parallel close tothe part. Multiple input caps can be connecteddepending upon the application
2. The PHASE copper trace serves two purposes; Inaddition to being the current path from the PowerStage package to the output inductor (L), it alsoserves as heat sink for the lower FET in the PowerStage package. The trace should be short and wideenough to present a low resistance path for thehigh current flow between the Power Stage and theinductor. This is done to minimize conductionlosses and limit temperature rise. Please note thatthe PHASE node is a high voltage and highfrequency switching node with high noisepotential. Care should be taken to minimizecoupling to adjacent traces. The reference layoutin Figure 31 shows a good balance between thethermal and electrical performance of Power Stage
3. Output inductor location should be as close aspossible to the Power Stage device for lowerpower loss due to copper trace resistance. Ashorter and wider PHASE trace to the inductorreduces the conduction loss. Preferably the PowerStage should be directly in line (as shown inFigure 32) with the inductor for space savings andcompactness
4. The POWERTRENCH Technology MOSFETsused in the Power Stage are effective atminimizing phase node ringing. It allows the partto operate well within the breakdown voltagelimits. This eliminates the need to have an externalsnubber circuit in most cases. If the designerchooses to use an RC snubber, it should be placedclose to the part between the PHASE pad and S2pins to dampen the high−frequency ringing
5. The driver IC should be placed close to the PowerStage part with the shortest possible paths for theHigh Side gate and Low Side gates through a widetrace connection. This eliminates the effect ofparasitic inductance and resistance between thedriver and the MOSFET and turns the devices onand off as efficiently as possible. At
higher−frequency operation this impedance canlimit the gate current trying to charge theMOSFET input capacitance. This will result inslower rise and fall times and additional switchinglosses. Power Stage has both the gate pins on thesame side of the package which allows for backmounting of the driver IC to the board. Thisprovides a very compact path for the drive signalsand improves efficiency of the part
6. S2 pins should be connected to the GND planewith multiple vias for a low impedance grounding.Poor grounding can create a noise transient offsetvoltage level between S2 and driver ground. Thiscould lead to faulty operation of the gate driverand MOSFET
7. Use multiple vias on each copper area tointerconnect top, inner and bottom layers to helpsmooth current flow and heat conduction. Viasshould be relatively large, around 8 mils to 10mils, and of reasonable inductance. Critical highfrequency components such as ceramic bypasscaps should be located close to the part and on thesame side of the PCB. If not feasible, they shouldbe connected from the backside via a network oflow inductance vias
SyncFET IS trademark of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries.POWERTRENCH is registered trademark of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or othercountries.
ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regardingthe suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specificallydisclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor therights of others.
98AON13659GDOCUMENT NUMBER:
DESCRIPTION:
Electronic versions are uncontrolled except when accessed directly from the Document Repository.Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.
ON Semiconductor and are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.ON Semiconductor reserves the right to make changes without further notice to any products herein. ON Semiconductor makes no warranty, representation or guarantee regardingthe suitability of its products for any particular purpose, nor does ON Semiconductor assume any liability arising out of the application or use of any product or circuit, and specificallydisclaims any and all liability, including without limitation special, consequential or incidental damages. ON Semiconductor does not convey any license under its patent rights nor therights of others.
98AON13659GDOCUMENT NUMBER:
DESCRIPTION:
Electronic versions are uncontrolled except when accessed directly from the Document Repository.Printed versions are uncontrolled except when stamped “CONTROLLED COPY” in red.
onsemi, , and other names, marks, and brands are registered and/or common law trademarks of Semiconductor Components Industries, LLC dba “onsemi” or its affiliatesand/or subsidiaries in the United States and/or other countries. onsemi owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property.A listing of onsemi’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. onsemi reserves the right to make changes at any time to anyproducts or information herein, without notice. The information herein is provided “as−is” and onsemi makes no warranty, representation or guarantee regarding the accuracy of theinformation, product features, availability, functionality, or suitability of its products for any particular purpose, nor does onsemi assume any liability arising out of the application or useof any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. Buyer is responsible for its productsand applications using onsemi products, including compliance with all laws, regulations and safety requirements or standards, regardless of any support or applications informationprovided by onsemi. “Typical” parameters which may be provided in onsemi data sheets and/or specifications can and do vary in different applications and actual performance mayvary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. onsemi does not convey any licenseunder any of its intellectual property rights nor the rights of others. onsemi products are not designed, intended, or authorized for use as a critical component in life support systemsor any FDA Class 3 medical devices or medical devices with a same or similar classification in a foreign jurisdiction or any devices intended for implantation in the human body. ShouldBuyer purchase or use onsemi products for any such unintended or unauthorized application, Buyer shall indemnify and hold onsemi and its officers, employees, subsidiaries, affiliates,and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or deathassociated with such unintended or unauthorized use, even if such claim alleges that onsemi was negligent regarding the design or manufacture of the part. onsemi is an EqualOpportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.