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 pushbutton， 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.