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Low Cost, Space Efficient, 3-Lead Reset Generator Circuits
Analog Devices offers a range of reset generator circuits designed for use in microprocessor-based systems to monitor power supply voltage levels from 5 V down to 2.5 V. Their
reset output signals are asserted whenever the supply voltage falls below a preset threshold level. Reset remains active for a fixed timeout period after the supply voltage has returned to a valid level, so that the supply has time to stabilize before the microprocessor starts up again. The various models provide a choice of active low or active high and push-pull or open-drain output stages.
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ADM803 Open-Drain Reset Generator
• Suitable for monitoring 2.5 V, 3 V, 3.3 V, and 5 V power supplies
*The ADM1813 and ADM1818 also feature manual reset capability.
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ADM6711/ADM6713 Reset Generators with Manual Reset in SC70
• Suitable for monitoring 2.5 V, 3 V, 3.3 V, and 5 V power supplies
• 140 ms minimum reset timeout
• Debounced manual reset input
• Active low push-pull reset output (ADM6711)
• Active low open-drain reset output (ADM6713)
• Low power consumption (12 A)
• Specified over –40°C to +125°C
• Available in 4-lead SC70 package
4-Lead Reset Generators with Manual Reset
The ADM811/ADM812, ADM6315, ADM6711/ADM6713, and ADM6384 offer a manual reset input, allowing a user to safely reset a microprocessor system by means of an external push-button switch.
ADM6384 Reset Generator with Manual Reset in SC70
• Suitable for monitoring 3 V, 3.3 V, and 5 V power supplies
• 140 ms minimum reset timeout
• Debounced manual reset input
• Active low push-pull reset output
• Specified over –40°C to +125°C
• Available in 4-lead SC70 package
APPLICATIONS
• Personal computers
• Consumer electronics
• Microcontroller-/microprocessor-based systems
• Handheld GPS units
• Pocket PCs
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Part Number
Reset Threshold Options (V) Min Timeout (ms)
Reset Output Stage Package Cross ReferenceActive Low Active High
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Watchdog Supervisory Circuits
Microprocessors need to be reset when code execution errors occur, as well as when supply voltages fall to invalid levels. A watchdog function can detect code execution errors by monitoring frequent logic transitions on a microprocessor’s output pin. If a transition is not detected within a certain time period, the watchdog circuit will initiate a reset signal that will take the microprocessor out of
its invalid state. Many ADI reset generator watchdog circuits also feature a power fail detection comparator that asserts an active low signal when the unregulated power supply voltage falls below a predetermined level. This power fail output can be used to generate a nonmaskable interrupt, which allows the microprocessor to implement a shutdown procedure before power is lost.
APPLICATIONS
• Microprocessor systems
• Computers
• Controllers
• Intelligent instruments
• Critical P monitoring
ADM8616 Watchdog Supervisory Circuits in 4-Pin SC70
In some computer applications, it is desirable to provide battery-backup support for external RAM, so that in the event of a power brownout,
a battery can supply power to the RAM unit and data stored by the microprocessor can be saved. In addition to providing precision voltage monitoring, watchdog timing, and power fail detection, many of our battery-backup parts can control the chip enable status of external RAM blocks to prevent a microprocessor from writing erroneous data during power-up, power-down, and brownout conditions.
ADM869x: Upgrade for Industry Standard ADM69X
• Lower power consumption (140 A)
• Faster gating of chip enable signals (3 ns)
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Super Sequencers
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ADM1062 to ADM1069: Multisupply Super Sequencers™ with Margining Control
The ADM1062 to ADM1069 family consists of configurable supervisory/sequencing devices that offer a single-chip solution for supply monitoring and sequencing in multisupply systems. The ADM1062 to ADM1069 have up to 10 programmable supply voltage monitor inputs. Voltages from 0.6 V to 14.4 V can be detected directly. Five of the inputs can also be configured as general-purpose logic inputs.
An on-chip 12-bit ADC allows readback of the supply voltages, offering an extra level of supply supervision. This can be used in a closed-loop system with four or six on-chip DACs for supply voltage adjustment and margining.
The ADM1062 to ADM1069 family has a versatile, programmable state machine sequencing engine. 512 bytes of on-chip EEPROM is available to store configuration parameters.
Features• Up to 10 supply fault detector inputs with programmable
thresholds—1% accuracy
• Up to five general-purpose logic inputs
• 10 fully programmable output drivers
• Internal charge pump for high-side drive of N-channel FET on six outputs
• Flexible, programmable, state machine-based sequencing engine
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ADM1085 to ADM1088: Simple Sequencers™ADM1085 to ADM1088: Simple Sequencers™ADM1085 to ADM1088: Simple Sequencers
The ADM1085 to ADM1088 Simple Sequencers provide an easy, yet powerful and flexible, solution to the problem of power supply sequencing. They offer programmable time delays from 5 s to several seconds and can be cascaded in a variety of ways to give sequencing of multiple power supplies. A choice of active-low or active-high outputs and push-pull or high voltage open-drain output
stages ensures compatibility with the widest possible range of voltage regulators and dc-to-dc converters. The ADM1085 to ADM1088 are available in a tiny, 6-lead SC70 package.
Features
• Provide time delays between enabling of regulators
• Can be cascaded with regulators for multiple supply sequencing
• Power supply monitoring from 0.6 V
• Output stages
• High voltage (up to 22 V) open-drain output (ADM1085/ADM1087)
• Push-pull outputs (ADM1086/ADM1088)
• Fixed (5 s typ) or capacitor adjustable time delays
• Enable input
• Low power consumption (15 A)
• Specified over –40°C to +125°C temperature range
Analog Devices, Inc.Europec/o Analog Devices SA17–19, rue Georges BesseParc de HauteTechnologie d’AntonyF-92182 Antony Cedex, FranceTel: 33.1.46.74.45.00Fax: 33.1.46.74.45.01
Analog Devices, Inc.Japan HeadquartersNew Pier TakeshibaSouth Tower Building1-16-1 Kaigan,Minato-ku, Tokyo 105-6891, JapanTel: 813.5402.8210Fax: 813.5402.1063
Analog Devices, Inc.Southeast Asia Headquarters39/F One Pacific Place88 QueenswayAdmiralty,Hong Kong, PRCTel: 852.2.506.9336Fax: 852.2.506.4755
Future Parts:New Low Power Reset and Watchdog Supervisory Circuits
3-Pin and 4-Pin Reset Circuits
ADM8609: < 1 A, 3-Pin Reset Circuit in SOT-663� • 1.39 V to 3.1 V Reset Trip Points� • 140 ms Reset TimeoutADM6328: 1 A, 3-Pin Reset Circuit in SOT-23 and SC70� • 2.93 V Reset Trip Point� • 100 ms Reset Timeout� • Pin Compatible with MAX6328ADM6804: 4 A, 4-Pin Manual Reset Circuit in SOT-143� • 2.93 V Reset Trip Point� • 100 ms Reset Timeout� • Pin Compatible with MAX6804ADM6444: 4-Pin Manual Reset Circuit in SOT-23� • 1.58 V to 4.63 V Reset Trip Points� • 140 ms Reset Timeout� • 6.72 s Manual Reset Setup Period� • Pin Compatible with MAX6444
5-Pin Reset Circuits
ADM6306: 5-Pin Dual Manual Reset Circuit in SOT-23� • 2.5 V to 5 V VCC Trip Points� • 1.25 V RSTIN Trip Point� • 1 ms to 1120 ms Reset Timeout Options� • Pin Compatible with MAX6306ADM8606: 5-Pin Dual Reset Circuit in SC70� • 0.84 V to 1.4 V VCC1 Trip Points� • 1.68 V to 2.93 V VCC2 Trip Points� • 1 ms to 1120 ms Reset Timeout Options
6-Pin and 8-Pin Manual Reset and Watchdog Circuits
ADM8708: 6-Pin Manual Reset Circuit in SC70� • 1.56 V to 4.63 V Trip Points� • 1 ms to 1120 ms Reset Timeout Options� • Manual Reset and 0.6 V Power Fail ComparatorADM6706: 8-Pin Watchdog Supervisory Circuit in SOT-23� • 2.19 V to 4.63 V Trip Points� • 140 ms Reset Timeout� • 1.6 s Watchdog Timeout� • Manual Reset and 0.6 V Power Fail Comparator