LMC6953 Datasheet, PDF (1/19 Pages) National Semiconductor (TI) – PCI Local Bus Power Supervisor

LMC6953
www.ti.com
SNVS132D – APRIL 1998 – REVISED APRIL 2013
LMC6953 PCI Local Bus Power Supervisor
Check for Samples: LMC6953
FEATURES
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•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 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
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 eliminates additional
discrete components.
Typical Application Circuits
Figure 1. On Mother Board
Figure 2. On Add-in Cards
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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