Datasheet LM3722, LM3723, LM3724 (Texas Instruments)

LM3722 , LM3723, LM3724 www.ti.com
SNVS154E – MAY 2001 – REVISED MARCH 2013
LM3722/LM3723/LM3724 5-Pin Microprocessor Reset Circuits Check for Samples: LM3722, LM3723, LM3724 FEATURES DESCRIPTION 1
The LM3722/LM3723/LM3724 microprocessor
• Precise Monitoring of 2.5V, 3.3V, and 5V 2
supervisory circuits monitor the power supplies in
Supply Voltages
microprocessor and digital systems. They provide a
• Fully Specified Over Temperature
reset to the microprocessor during power-up, power-
– Industrial: −40°C to +85°C
down, brown-out conditions, and manual reset.
– Extended: −40°C to +125°C
The LM3722/LM3723/LM3724 asserts a reset signal
• 100 ms Minimum Power-On Reset pulse Width,
whenever the supply decreases below the factory-
190 ms Typical:
programmed reset threshold. Reset will be asserted for at least 100ms even after VCC rises above the
– Active-Low RESET Output (LM3722)
reset threshold.
– Active-High RESET Output (LM3723)
The LM3722 has an active-low RESET push-pull
– Active-Low RESET Open Drain Output
output. The LM3723 has an active-high RESET push-
(LM3724)
pull output. The LM3724 has an active-low open-drain
• Guaranteed RESET Output Valid for VCC ≥ 1V
RESET output.
• Low Supply Current, 6µA Typical
Three standard reset voltage options are available,
• Power Supply Transient Immunity
suitable for monitoring 5V, 3.3V, and 2.5V supply voltages. Additional reset voltages are also available;
• Compatible with MAX811/812 Applications
contact Texas Instruments for details.
APPLICATIONS
With a low supply current of only 6µA, the LM3722/LM3723/LM3724 are ideal for use in portable
• Microprocessor Systems
equipment. The LM3722/LM3723/LM3724 are
• Computers
available in the 5-pin SOT-23 package.
• Controllers • Intelligent Instruments • Portable/Battery-Powered Equipment Typical Application Circuits
VCC VCC V V CC V CC V CC CC RL
LM3722
P
P LM3724
P
P LM3723
RESET RESET RESET MR MR RESET *(RESET) INPUT INPUT PUSHBUTTON PUSHBUTTON SWITCH SWITCH GND GND GND GND
Figure 1. Typical Application Circuit Figure 2. Typical Application Circuit with RL Connection
1 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. All trademarks are the property of their respective owners. 2 PRODUCTION DATA information is current as of publication date. Copyright © 2001–2013, Texas Instruments Incorporated Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Document Outline FEATURES APPLICATIONS DESCRIPTION Typical Application Circuits Connection Diagram Absolute Maximum Ratings Electrical Characteristics Typical Performance Characteristics Timing Diagram Circuit Information RESET OUTPUT RESET THRESHOLD MANUAL RESET INPUT (MR) Applications Information BENEFITS OF PRECISION RESET THRESHOLDS ENSURING A VALID RESET OUTPUT DOWN TO VCC = 0V OPEN DRAIN OUTPUT (LM3724) NEGATIVE-GOING VCC TRANSIENTS INTERFACING TO µPS WITH BIDIRECTIONAL RESET PINS Typical Application Circuits Revision History