IC POWER SUP PCI LOCAL BUS 8SOIC

LMC6953CMX/NOPB

Manufacturer Part NumberLMC6953CMX/NOPB
DescriptionIC POWER SUP PCI LOCAL BUS 8SOIC
ManufacturerNational Semiconductor
TypeMulti-Voltage Supervisor
LMC6953CMX/NOPB datasheet
 


Specifications of LMC6953CMX/NOPB

Number Of Voltages Monitored2OutputOpen Drain or Open Collector
ResetActive LowReset Timeout100 ms Minimum
Voltage - Threshold3.3V, 5VOperating Temperature-40°C ~ 85°C
Mounting TypeSurface MountPackage / Case8-SOIC (3.9mm Width)
Lead Free Status / RoHS StatusLead free / RoHS CompliantOther names*LMC6953CMX
*LMC6953CMX/NOPB
LMC6953CMX
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LMC6953
PCI Local Bus Power Supervisor
General Description
The LMC6953 is a voltage supervisory chip designed to
meet PCI (Peripheral Component Interconnect) Specifica-
tions 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 accu-
rately determines all the threshold voltages. The internal
reset delay circuitry eliminates additional discrete compo-
nents.
Typical Application Circuits
On Mother Board
© 2005 National Semiconductor Corporation
Features
n Compliant to PCI specifications revision 2.1.
n Under and over voltage detectors for 5V and 3.3V
n Power failure detection (5V falling under 3.3V by
300 mV max)
n Manual reset input pin
n Guaranteed RESET assertion at V
n Integrated reset delay circuitry
n Open drain output
n Adjustable reset delay
n Response time for over and under voltage detection:
490 ns Max
n Power failure response time: 90 ns Max
n Requires minimal external components
Applications
n Desktop PCs
n PCI-Based Systems
n Network servers
01284623
DS012846
February 2005
= 1.5V
DD
On Add-in Cards
01284624
www.national.com

LMC6953CMX/NOPB Summary of contents

  • Page 1

    ... The internal reset delay circuitry eliminates additional discrete compo- nents. Typical Application Circuits On Mother Board © 2005 National Semiconductor Corporation Features n Compliant to PCI specifications revision 2.1. n Under and over voltage detectors for 5V and 3.3V n Power failure detection (5V falling under 3.3V by ...

  • Page 2

    Connection Diagram Ordering Information Package 8-Pin Small Outline www.national.com 8–Pin SO 01284602 Top View Industrial Temp Range NSC −40˚C to +85˚C Drawing LMC6953CM M08A LMC6953CMX 2 Supplied As Rails 2.5k Tape and Reel ...

  • Page 3

    ... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. ESD Tolerance (Note 2) Human Body Model Machine Model Voltage at Input Pin Supply Voltage Current at Output Pin Current at Power Supply Pin (Note 3) ...

  • Page 4

    AC Electrical Characteristics Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. For guaranteed specifications ...

  • Page 5

    Typical Performance Characteristics Unless otherwise specified 25˚C A Supply Current vs Temperature Power-Up Supply Voltage vs Temperature V vs Temperature L5 Output Voltage vs Supply Voltage 01284604 01284609 01284606 5 01284612 V vs Temperature H5 01284605 V vs ...

  • Page 6

    Typical Performance Characteristics V vs Temperature L3.3 Under-Voltage Response Time vs Temperature PULL-UP www.national.com Unless otherwise specified, T Over-Voltage Response Time 01284608 Power Failure Response Time 01284614 01284619 6 = 25˚C (Continued Temperature 01284613 ...

  • Page 7

    Typical Performance Characteristics Reset Delay vs C EXT Block Diagram of the LMC6953 ** All five comparators’ positive power supplies are connected to V Unless otherwise specified, T Reset Delay vs Temperature 01284610 25˚C (Continued) A with ...

  • Page 8

    Truth Table Power 5V Failure Over-Voltage Fail X X Fail Don’t Care Pin Description Pin Name input supply voltage. This pin supplies power to the ...

  • Page 9

    Application Note (Continued) connected with a constant 3.3 V and pins 1 and 2 are DC connected to a separate power supply that continues to vary from 3.3V to 6V. 5V AND V PINS DD By having the 5V and ...

  • Page 10

    Typical Application Circuits On Mother Board with Capacitor as a Back-up Power Supply www.national.com On Mother Board 01284617 01284626 On Add-In Cards 10 01284618 ...

  • Page 11

    ... BANNED SUBSTANCE COMPLIANCE National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2. ...