description
The H (metal round cap), J (ceramic), and K (metal round cap) packages supplied by Lingliert are now discontinued.
The LTC®690 series provides full power monitoring and battery control functions for microprocessor reset, battery backup, CMOS RAM write protection, power failure alarm, and watchdog timing. A precise internal voltage reference and comparator circuit monitors the power lines. When the tolerance range is exceeded, the reset output will be forced into an operating state, and the chip enable output will unconditionally write protect the external memory. In addition, the RESET output will be guaranteed to be logically low, even when VCC is as low as 1V.
The LTC690 series utilizes a charge pump NMOS power switch to power active CMOS RAM and is designed for low dropout and low supply current. When the main power supply is lost, the secondary power supply (connected to the battery input pin) will power the RAM in standby state via a high-efficiency PMOS switch.
To provide early warning when a power failure is imminent, the LTC690 Series offers an internal comparator with user-defined thresholds. In addition, an internal watchdog timer is provided that will force the reset pin to enter the running state when the watchdog input is not transformed before a preset timeout period.