DS1233

DS1233 5V EconoReset www.dalsemi.com FEATURES Automatically restarts microprocessor after power failure Monitors pushbutton for external override Internal circuitry debounces pushbutton switch Maintains reset for 350 ms after VCC returns to an in-tolerance condition or pushbutton released Accurate 5%, 10% or 15% microprocessor 5V power supply monitoring Reduces need for discrete components Precision temperature-compensated voltage reference and voltage sensor Low-cost TO-92 package or surface-mount SOT-223 package Internal 5kΩ=pull-up resistor Operating temperature of -40°C to +85°C PIN ASSIGNMENT DALLAS DS1233 Econo Reset 1 1 2 3 1 2 3 TO-92 PACKAGE See Mech. Drawings Section 2 4 3 SOT-223 PACKAGE See Mech. Drawings Section PIN DESCRIPTION PIN 1 PIN 2 PIN 3 PIN 4 GROUND RESET VCC GROUND (SOT-223 ONLY) DESCRIPTION The DS1233 EconoReset monitors two vital conditions for a microprocessor: power supply and external override. A precision temperature compensated reference and comparator circuit are used to monitor the status of the power supply (VCC). When an out-of-tolerance condition is detected, an internal power-fail signal is generated which forces reset to the active state. When VCC returns to an in-tolerance condition, the reset signal is kept in the active state for approximately 350 ms to allow the power supply and processor to stabilize. The second function of the DS1233 is pushbutton reset control. The DS1233 debounces a pushbutton closure and will generate a 350...