Product Summary

The TC74HC221A is a fully-integrated power supply monitor, watchdog and battery backup circuit in a space-saving 8-pin package. Application areas of the TC74HC221A include all microprocessor-based Systems, test Equipment, instrumentation.

Parametrics

TC74HC221A absolute maximum ratings: (1)Voltage (Any Pin) with Respect to Ground：– 0.3 to VCC + 0.3V; (2)Operating Temperature Range：– 40°C to +85°C; (3); (4)Storage Temperature Range：– 65°C to +150°C; (5)Lead Temperature (Soldering, 10 sec)：+300°C.

Features

TC74HC221A features: (1)Maximum Functional Integration: Precision Power Supply Monitor,Watchdog Timer, External RESET Override, Threshold Detector and Battery Backup Controller in an 8-Pin Package; (2)Generates Power-on RESET and Guards Against Unstable Processor Operation Resulting from Power "Brown-out"; (3)Automatically Halts and Restarts an Out-of- Control Microprocessor; (4)Output Can be Wire-ORed, or Hooked to Manual RESET Pushbutton Switch; (5)Watchdog Disable Pin for Easier Prototyping (TC70); (6)Voltage Monitor for Power Fail or Low Battery Warning (TC71).

Diagrams

TC74HC221A block diagram

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