LMC6953

LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 LMC6953 PCI Local Bus Power Supervisor Check for Samples: LMC6953 FEATURES 1 2 Compliant to PCI Specifications Revision 2.1. Under and Over Voltage Detectors for 5V and 3.3V Power Failure Detection (5V Falling Under 3.3V by 300 mV Max) Manual Reset Input Pin Specified RESET Assertion at VDD = 1.5V Integrated Reset Delay Circuitry Open Drain Output Adjustable Reset Delay Response Time for Over and Under Voltage Detection: 490 ns Max Power Failure Response Time: 90 ns Max Requires Minimal External Components APPLICATIONS Desktop PCs PCI-Based Systems Network servers DESCRIPTION The LMC6953 is a voltage supervisory chip designed to meet PCI (Peripheral Component Interconnect) Specifications Revision 2.1. It monitors 5V and 3.3V power supplies. In cases of power-up, power-down, brown-out, power failure and manual reset interrupt, the LMC6953 provides an active low reset. RESET holds low for 100 ms after both 5V and 3.3V powers recover, or after manual reset signal returns to high state. The external capacitor on pin 8 adjusts the reset delay. This part is ideal on PCI motherboards or add-in cards to ensure the integrity of the entire system when there is a fault condition. The active low reset sets the microprocessor or local device in a known state. The LMC6953 has a built-in bandgap reference that accurately determines all the threshold voltages. The internal reset delay circuitry elim...