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NATIONAL LM3702 LM3703 User's Manual

Summary

These microprocessor supervisory circuits are essential for critical power monitoring in embedded controllers, intelligent instruments, and automotive systems. The LM3702/LM3703 series monitors supply voltage integrity, providing reliable reset signals during power-up, brownouts, or based on manual input. This manual details the functionality, customizable threshold settings (2.2V to 5.0V), and the specialized Low Line Output for early power failure warnings. Engineered in a minimal micro SMD package, these supervisors ensure sustained system stability.

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Page 1 Text Content

September

LM 3702/LM icroprocessor upervisory ircuits ith Low Line utput and anual R eset

LM3702/LM3703 Microprocessor Supervisory Circuits with Low Line Output and Manual Reset

No external components required

General Description

Manual-Reset input

The LM3702/LM3703 series of microprocessor supervisory

RESET (LM3702) or RESET (LM3703) outputs

circuits provide the maximum flexibility for monitoring power

Precision supply voltage monitor

supplies and battery controlled functions in systems without

Factory programmable Reset Timeout Delay

backup batteries. The LM3702/LM3703 series are available

in 9-bump micro SMD package. Available in micro SMD package for minimum footprint ±0.5% Reset threshold accuracy at room temperature

Built-in features include the following:

±2% Reset threshold accuracy over temperature

Reset: Reset is asserted during power-up, power-down, and

extremes brownout conditions. RESET is guaranteed down to VCC of Reset assertion down to 1V VCC (RESET option only)

µA VCC supply current

Manual Reset Input: An input that asserts reset when pulled low.

Applications

Low Line Output: This early power failure warning indicator

goes low when the supply voltage drops to value which is Embedded Controllers and Processors

2% higher than the reset threshold voltage. Intelligent Instruments

Automotive Systems Features Critical µP Power Monitoring

Standard Reset Threshold voltage: 3.08V Custom Reset Threshold voltages: For other voltages between 2.2V and 5.0V in 10m V increments, contact National Semiconductor Corp.

Typical Application

National Semiconductor Corporation DS200115 www.national.com

Page Summary Contents For NATIONAL LM3702 LM3703 User's Manual

Page 1 September LM 3702/LM icroprocessor upervisory ircuits ith Low Line utput and anual R eset LM3702/LM3703 Microprocessor Supervisory Circuits with Low Line Output and Manual Reset No external components...
Page 2 Connection Diagram LM /L (looking from the coating side) micro SMD Bump Package BPA09 Pin Descriptions Bump No. Name Function A1 MR Manual-Reset input. When MR is less than VMRT (Manual Reset Threshol...
Page 3 Block Diagram LM 3702/LM www.national.com3
Page 4 Ordering Information LM /L *For other voltages between 2.2V and 5.0V, please contact National Semiconductor sales office. LM3702/LM3703 Reset Package Part Number Output Timeout Marking Period LM3702XC...
Page 5 Absolute Maximum Ratings (Note 1) Power Dissipation (Note 3) LM 3702/LM If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Operating Ratings ...
Page 6 LM3702/LM3703 Series Electrical Characteristics (Continued) Limits in the standard typeface are for TJ 25˚C and limits in boldface type apply over full operating range. Unless otherwise LM /L specifie...
Page 7 Typical Performance Characteristics LM 3702/LM Supply Current vs Supply Voltage 3.3V Supply Current vs Temperature Normalized Reset Threshold Voltage vs Temperature Reset Timeout Period vs VCC Max. Tr...
Page 8 Typical Performance Characteristics (Continued) LM /L Low-Line Comparator Propagation Delay vs Temperature www.national.com
Page 9 timeout period expires after MR rises above VMRT. Use MR Circuit Information with digital logic to assert or to daisy chain supervisory LM 3702/LM circuits. It may be used as another low-line comparat...
Page 10 Timing Diagrams LM /L FIGURE 1. LM3702 Reset Time with MR FIGURE 2. LLO Output www.national.com
Page 11 Typical Application Circuits LM 3702/LM FIGURE 3. LM3703 Power-On Delay www.national.com11
Page 12 Typical Application Circuits (Continued) LM /L FIGURE 4. Regulator/Switch with Long-Term Overvoltage Lockout Prevents Overdissipation in Linear Regulator FIGURE 5. Switch Debouncer www.national.com
Page 13 Physical Dimensions inches (millimeters) LM unless 3702/LM otherwise noted icroprocessor upervisory ircuits ith Low Line utput and anual R eset NOTES: UNLESS OTHERWISE SPECIFIED 1. EPOXY COATING 2. 63...

Manual Details

Brand National
Pages 13
File Size 222.46 KB
Published June 17, 2026
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Frequently Asked Questions

How do I get an early warning of imminent power failure?

Use the Low-Line Output (C3); it goes low when the supply voltage drops to a value 2% higher than the reset threshold.

Are there limitations on setting custom reset thresholds?

You can request thresholds between 2.2V and 5.0V in 10mV increments, but you must contact National Semiconductor sales office for these customized voltages.

What conditions does the RESET output monitor besides sudden power loss?

The RESET output monitors brownout conditions and is guaranteed down to 1V CC, providing maximum flexibility for monitoring power supplies.

Can this component be used in critical life support or medical device systems?

No, National Semiconductor requires express written approval before these products can be used as critical components in life support devices.