Supervisory Circuit with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23

The ADM823 / ADM824 / ADM825 are supervisory circuits that monitor power supply voltage levels and code execution integrity in microprocessor-based systems. In addition to providing power-on reset signals, an on-chip watchdog timer can reset the microprocessor if it fails to strobe within a preset timeout period. A reset signal can also be asserted by an external push-button, through a manual reset input. The three parts feature different combinations of watchdog input, manual reset input, and output stage configuration, as shown in Table 1.

These parts are available in a choice of seven reset threshold options ranging from 2.19 V to 4.63 V. The reset and watchdog timeout periods are fixed at 140 ms (minimum) and 1.6 sec (typical), respectively.

The ADM823 / ADM824 / ADM825 are available in 5-lead SC70 and SOT-23 packages and typically consume only 5 μA, making them suitable for use in low power, portable applications.

APPLICATIONS

* Microprocessor systems

* Computers

* Controllers

* Intelligent instruments

* Portable equipment

* Precision 2.5 V to 5 V power supply monitor

* 7 reset threshold options:

2.19 V to 4.63 V

* 140 ms (minimum) reset timeout

* Manual reset input (ADM823, ADM825)

* Low power consumption (5 μA)