ADM6821:  Low Voltage Supervisory Circuit with Watchdog, Manual Reset and Active-High, Push-Pull Reset Output

The ADM6821-ADM6825 are supervisory circuits which monitor power supply voltage levels and code execution integrity in microprocessor-based systems. As well as 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 means of 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.

Each part is available in a choice of 9 reset threshold options ranging from 1.58V to 4.63V. The reset and watchdog timeout periods are fixed at 140ms (min) and 1.6s (typ), respectively.

The ADM6821-ADM6825 are available in 5-lead SOT-23 packages and typically consume only 3µA, making them suitable for use in low power portable applications.