TC71 Datasheet | TelCom

1 TC70/71 MICROMASTER™ - SYSTEM SUPERVISOR WITH POWER SUPPLY MONITOR, WATCHDOG AND BATTERY BACKUP Features s Maximum Functional Integration: Precision Power Supply Monitor, Watchdog Timer, External RESET Override, Threshold Detector and Battery Backup Controller in an 8-Pin Package Generates Power-on RESET and Guards Against Unstable Processor Operation Resulting from Power "Brown-out" Automatically Halts and Restarts an Out-ofControl Microprocessor Output Can be Wire-ORed, or Hooked to Manual RESET Pushbutton Switch Watchdog Disable Pin for Easier Prototyping (TC70) Voltage Monitor for Power Fail or Low Battery Warning (TC71) Available in 8-Pin Plastic DIP or 8-Pin SOIC Packages Cost Effective 2 3 4 5 6 7 GENERAL DESCRIPTION The TC70/71 is a fully-integrated power supply monitor, watchdog and battery backup circuit in a space-saving 8-pin package. When power is initially applied, the TC70/71 holds the processor in its reset state for a minimum of 500msec after VCC is in tolerance to ensure stable system start-up. After start-up, processor sanity is monitored by the on-board watchdog circuit. The processor must provide periodic highto-low level transitions to the TC70/71 to verify proper execution. Should the processor fail to supply this signal within the specified timeout period, an out-of-control processor is indicated and the TC70/71 issues a momentary processor reset as a result. The TC70 also Features a watchdog disable pin to facilitate system test and debug. The output of the TC70/71 can be wire-ORed to a pushbutton switch (or electronic signal) to reset the processor. When connected to a push-button switch, the TC70/71 provides contact debounce. The integrated battery backup circuit on-board the TC70/ 71 converts CMOS RAM into nonvolatile memory by first...