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LMC6953

www.ti.com

SNVS132D –APRIL 1998–REVISED APRIL 2013

LMC6953 PCI Local Bus Power Supervisor

Check for Samples: LMC6953

FEATURES

DESCRIPTION

The LMC6953 is a voltage supervisory chip designed

• Compliant to PCI Specifications Revision 2.1.

to meet PCI (Peripheral Component Interconnect)

• Under and Over Voltage Detectors for 5V and

Specifications Revision 2.1. It monitors 5V and 3.3V

3.3V

power supplies. In cases of power-up, power-down,

• Power Failure Detection (5V Falling Under 3.3V

brown-out, power failure and manual reset interrupt,

the LMC6953 provides an active low reset. RESET

by 300 mV Max)

holds low for 100 ms after both 5V and 3.3V powers

• Manual Reset Input Pin

recover, or after manual reset signal returns to high

• Specified RESET Assertion at V

= 1.5V

state. The external capacitor on pin 8 adjusts the

• Integrated Reset Delay Circuitry

reset delay.

• Open Drain Output

This part is ideal on PCI motherboards or add-in

cards to ensure the integrity of the entire system

• Adjustable Reset Delay

when there is a fault condition. The active low reset

• Response Time for Over and Under Voltage

sets the microprocessor or local device in a known

Detection: 490 ns Max

state.

• Power Failure Response Time: 90 ns Max

The LMC6953 has a built-in bandgap reference that

• Requires Minimal External Components

accurately determines all the threshold voltages. The

internal reset delay circuitry eliminates additional

APPLICATIONS

discrete components.

• Desktop PCs

• PCI-Based Systems

• Network servers

Typical Application Circuits

Figure 1. On Mother Board Figure 2. On Add-in Cards

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

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.

Summary of content (19 pages)

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LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 LMC6953 PCI Local Bus Power Supervisor Check for Samples: LMC6953 FEATURES 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.
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LMC6953 SNVS132D – APRIL 1998 – REVISED APRIL 2013 www.ti.com Connection Diagram Figure 3. 8–Pin SOIC Top View These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
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LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 DC ELECTRICAL CHARACTERISTICS Unless otherwise specified, all boldface limits specified for TJ = −40°C to +85°C, VDD = 5V, RPULL-UP = 4.7 kΩ and CEXT = 0.01 μF. Typical numbers are room temperature (25°C) performance. Symbol VH5 Parameter Conditions VDD Over-Voltage Threshold TJ = 0°C to 70°C (1) TJ = −40°C to 85°C VL5 VDD Under-Voltage Threshold TJ = 0°C to 70°C (1) TJ = −40°C to 85°C VH3.3 3.
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LMC6953 SNVS132D – APRIL 1998 – REVISED APRIL 2013 www.ti.com LMC6953 TIMING DIAGRAM Note: tRESET, tD and tPF are not to scale.
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LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise specified, TA = 25°C Supply Current vs Temperature Output Voltage vs Supply Voltage Figure 4. Figure 5. Power-Up Supply Voltage vs Temperature VH5 vs Temperature Figure 6. Figure 7. VL5 vs Temperature VH3.3 vs Temperature Figure 8. Figure 9.
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LMC6953 SNVS132D – APRIL 1998 – REVISED APRIL 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C 6 VL3.3 vs Temperature Over-Voltage Response Time vs Temperature Figure 10. Figure 11. 3Under-Voltage Response Time vs Temperature Power Failure Response Time vs Temperature Figure 12. Figure 13. VOL vs RPULL-UP IOL vs RPULL-UP Figure 14. Figure 15.
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LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Unless otherwise specified, TA = 25°C Reset Delay vs CEXT Reset Delay vs Temperature with CEXT = 0.01 μF Figure 16. Figure 17.
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LMC6953 SNVS132D – APRIL 1998 – REVISED APRIL 2013 www.ti.com BLOCK DIAGRAM OF THE LMC6953 ** All five comparators' positive power supplies are connected to VDD TRUTH TABLE (1) Power Failure (1) 5V Over-Voltage 5V Under-Voltage 3.3V Over-Voltage 3.
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LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 APPLICATION NOTE HOW THE LMC6953 FUNCTIONS The LMC6953 is a power supply supervisor with its performance specifications compliant to PCI Specifications Revision 2.1. The chip monitors power-up, power-down, brown-out, power failure and manual reset interrupt situations. During power-up, the LMC6953 holds RESET low for 100 ms after both 5V and 3.3V are within specified windows. It asserts reset in 490 ns when a brown-out is detected.
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LMC6953 SNVS132D – APRIL 1998 – REVISED APRIL 2013 www.ti.com EVALUATING THE LMC6953 To Measure Over-Voltages And Under-Voltages Connect a 3.3V DC to the 3.3V pin and a 5V DC to the VDD and the 5V pins (VDD and 5V pins are shorted). RESET output is high because voltages are within window. These voltages should be monitored. While keeping the 3.3V constant, increase the 5V DC signal until a RESET low is detected. The point on the 5V DC signal at which RESET changes from high to low is the 5V over-voltage.
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LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 Figure 20. Power Failure Waveforms Typical Application Circuits Figure 21. On Mother Board Figure 22.
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LMC6953 SNVS132D – APRIL 1998 – REVISED APRIL 2013 www.ti.com Figure 23.
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LMC6953 www.ti.com SNVS132D – APRIL 1998 – REVISED APRIL 2013 REVISION HISTORY Changes from Revision C (April 2013) to Revision D • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 18-Oct-2013 In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LMC6953CMX/NOPB Package Package Pins Type Drawing SOIC D 8 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 12.4 Pack Materials-Page 1 6.5 B0 (mm) K0 (mm) P1 (mm) 5.4 2.0 8.0 W Pin1 (mm) Quadrant 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LMC6953CMX/NOPB SOIC D 8 2500 367.0 367.0 35.
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