Product Overview
The ADM691ARZ-REEL is an ADI microprocessor supervisory circuit providing reset, watchdog, and power-fail detection. 4.65V reset threshold for 5V systems. 1.6s watchdog timeout. Adjustable power-fail comparator via PFI/PFO pins. Active-low push-pull reset output. SOIC-8 tape and reel.
Key Specifications
| Type | Microprocessor Supervisory Circuit |
| Function | Reset, Watchdog, Power Fail |
| Reset Threshold | 4.65V (5V – 7%) |
| Watchdog Timeout | 1.6 s typ |
| Power Fail Input | Adjustable via PFI/PFO |
| Reset Output | Active low push-pull |
| Supply Voltage | 4.5V to 5.5V |
| Operating Temp | -40 to +85C |
| Package | SOIC-8 |
Working Principle
The ADM691 integrates three supervisory functions: (1) Reset generator asserts RESET during power-up, power-down, and brownout conditions when VCC falls below 4.65V. Reset remains active for 50ms after VCC returns above threshold. (2) Watchdog timer requires periodic toggling of the WDI input; if not serviced within 1.6s, WDO asserts low. (3) Power-fail comparator monitors an uncommitted PFI input and drives PFO low when PFI falls below 1.3V, enabling early power-fail warning before VCC drops below the reset threshold.
Applications
- Microprocessor reset
- Watchdog supervision
- Power-fail warning
- System monitoring