Microprocessor

Supervisory Circuits

ADM8690/ADM8691/ADM8692/ADM8693/ADM8695

Rev. B

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FEATURES

Upgrade for ADM690 to ADM695, MAX690 to MAX695

Specified over temperature

Low power consumption (0.7 mW)

Precision voltage monitor

Reset assertion down to 1 V V

CC

Low switch on resistance 0.7 Ω normal, 7 Ω in backup

High current drive (100 mA)

Watchdog timer: 100 ms, 1.6 s, or adjustable

400 nA standby current

Automatic battery backup power switching

Extremely fast gating of chip enable signals (3 ns)

Voltage monitor for power fail

Available in TSSOP package

APPLICATIONS

Microprocessor systems

Computers

Controllers

Intelligent instruments

Automotive systems

PRODUCT HIGHLIGHTS

The ADM8690 and ADM8692 are available in 8-lead, PDIP

packages and provide:

1. Power-on reset output during power-up, power-down, and

brownout conditions. The RESET output remains

2. Battery backup switching for CMOS RAM, CMOS

microprocessor, or other low power logic.

3. A reset pulse if the optional watchdog timer has not been

toggled within a specified time.

4. A 1.3 V threshold detector for power-fail warning, low battery

detection, or to monitor a power supply other than 5 V.

The ADM8691, ADM8693, and ADM8695 are available in 16-lead

PDIP and small outline packages (including TSSOP) and

provide three additional functions:

1. Write protection of CMOS RAM or EEPROM.

2. Adjustable reset and watchdog timeout periods.

3. Separate watchdog timeout, backup battery switchover, and

FUNCTIONAL BLOCK DIAGRAMS

RESET

1.3V

RESET

WATCHDOG

TRANSITION DETECTOR

(1.6s)

ADM8690/

ADM8692

WATCHDOG

INPUT (WDI)

POWER FAIL

INPUT (PFI)

POWER FAIL

OUTPUT (PFO)

4.40V (ADM8692)

Figure 1. ADM8690/ADM8692

1.3V

LOW LINE

RESET

RESET

OSC IN

OSC SEL

BATT ON

ADM8691/

ADM8693/

ADM8695

RESET AND

WATCHDOG

TIME BASE

RESET

GENERATOR

WATCHDOG

TRANSITION DETECTOR

WATCHDOG

TIMER

POWER FAIL

INPUT (PFI)

WATCHDOG

INPUT (WDI)

POWER FAIL

OUTPUT (PFO)

WATCHDOG

OUTPUT (WDO)

4.40V (ADM8693)

Figure 2. ADM8691/ADM8693/ADM8695