LMC6953  Product Folder

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 eliminates additional discrete components.

• 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
• Guaranteed RESET# assertion at V_DD = 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

• Desktop PCs
• PCI-Based Systems
• Network servers