The CD705A, CD706A, CD707A, CD708Amicroprocessor supervisory circuits are suitable for monitoring 5V power supplies/batteries and microprocessor activity. The CD705A/CD706A provide power-supply monitoring circuitry that generate a reset output during power-up,power-down, and brownout conditions. The reset output remains operational with VCC as low as 1V. Independent watchdog monitoring circuitry is also provided. This is activated if the watchdog input has not been toggled within 1.60 sec. In addition, there is a 1.25V threshold detector to warn of power failures, to detect low battery conditions, or to monitor an additional power supply. An active low, debounced manual reset input ( MR) is also included.
The CD705A and CD706A are identical except for the reset threshold monitor levels, which are 4.65V and 4.40V, respectively. The CD707A and CD708A provide a similar functionality to the CD705A and CD706A and only differ in that a watchdog timer function is not available. Instead, an active high reset output (RESET) is available as well as the active low reset output(RESET ). The CD707A and CD708A are identical except for the reset threshold monitor levels, which are 4.65V and 4.40V, respectively.All devices are available in narrow 8-lead SOIC packages.