CS8141 Datasheet | Cherry Semiconductor Corporation

Description The CS8140 is a 5V Watchdog Regulator with protection circuitry and three logic control functions that allow a microprocessor to control its own power supply. The CS8140 is designed for use in automotive, switch mode power supply post regulator, and battery powered systems. Basic regulator performance characteristics include a low noise, low drift, 5V ± 4% precision output voltage with low dropout voltage (1.25V @ IOUT = 500m A) and low quiescent current (7m A @ IOUT = 500m A). On board short circuit, thermal, and overvoltage protection make it possible to use this regulator in particularly harsh operating environments. The Watchdog logic function monitors an input signal (WDI) from the microprocessor or other signal source. When the signal frequency moves outside externally programmable window limits, a RESET signal is generated ( RESET ). An external capacitor (CDELAY) programs the watchdog window frequency limits as well as the power on reset (POR) and RESET delay. The RESET function is activated by any of three conditions: the watchdog signal moves outside of its preset limits; the output voltage drops out of regulation by more than 4.5%; or the IC is in its power up sequence. The RESET signal is independent of VIN and reliable down to VOUT = 1V. In conjunction with the Watchdog, the ENABLE function controls the regulatorÕs power consumption. The CS8140Õs output stage and its attendant circuitry are enabled by setting the ENABLE lead high. The regulator goes into sleep mode (IOUT = 250µA) when the ENABLE lead goes low and the watchdog signal moves outside its preset window limits. This unique bination of control functions in the CS8140 gives the microprocessor control over its own power down sequence: i.e. it gives the microprocessor the flexibility to perform housekeeping functions before it powers down. The CS8141 has the same features as the CS8140, except that the CS8141 only responds to input signals (WDI) which are below the preset watchdog...