View ds1834 datasheet:

DS1834/A/D Dual EconoReset with Pushbutton www.dalsemi.com FEATURES PIN ASSIGNMENT 5V power-on reset 3.3VIN 5VIN 1 8 3.3V power-on reset 2 5V RST 7 3.3V RST Internal power is drawn from higher of either the 5VIN input or the 3.3VIN input 5V TOL 3 6 3.3V TOL Excellent for systems designed to operate 4 5 PBRST GND with dual power supplies DS1834 8-Pin DIP (300-mil) Asserts resets during power transients Pushbutton reset input for system override 3.3VIN 5VIN 1 8 Maintains reset for 350 ms after VCC returns 5V RST 2 7 3.3V RST to an in-tolerance condition 5V TOL 3 6 3.3V TOL Reduces need for discrete components GND 4 5 PBRST Precision temperature-compensated voltage DS1834 8-Pin SOIC (150-mil) reference and voltage sensor 8-pin DIP, 8-pin SOIC, and 8-p