ADM823

Preliminary Technical Data FEATURES Supervisory Circuits with Watchdog and Manual Reset in 5-Lead SC70 and SOT-23 ADM823/ADM824/ADM825 FUNCTIONAL BLOCK DIAGRAM ADM823 VCC VREF VCC RESET GENERATOR Precision 2.5 V to 5 V power supply monitor 7 reset threshold options: 2.19 V to 4.63 V 140 ms (min) reset timeout Watchdog timer with 1.6s timeout (ADM823, ADM824) Manual reset input (ADM823, ADM825) Push-pull output stages: RESET (ADM823) RESET, RESET (ADM824/ADM825) Low power consumption (3 µA) Guaranteed reset output valid to VCC = 1 V Power supply glitch immunity Specified over automotive temperature range 5-lead SC70 and SOT-23 packages RESET MR DEBOUNCE WATCHDOG DETECTOR 04534-0-001 GND WDI Figure 1. APPLICATIONS Microprocessor systems Computers Controllers Intelligent instruments Portable equipment GENERAL DESCRIPTION The ADM823/ADM824/ADM825 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 seven reset threshold options ranging from 2.19 V to 4.63 V. The reset an...