LM3722 Datasheet, PDF (1/19 Pages) National Semiconductor (TI) – 5-Pin Microprocessor Reset Circuits

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
1
•2 Precise Monitoring of 2.5V, 3.3V, and 5V
Supply Voltages
• Fully Specified Over Temperature
– Industrial: −40°C to +85°C
– Extended: −40°C to +125°C
• 100 ms Minimum Power-On Reset pulse Width,
190 ms Typical:
– Active-Low RESET Output (LM3722)
– Active-High RESET Output (LM3723)
– Active-Low RESET Open Drain Output
(LM3724)
• Guaranteed RESET Output Valid for V_CC ≥ 1V
• Low Supply Current, 6µA Typical
• Power Supply Transient Immunity
• Compatible with MAX811/812 Applications
APPLICATIONS
• Microprocessor Systems
• Computers
• Controllers
• Intelligent Instruments
• Portable/Battery-Powered Equipment
DESCRIPTION
The LM3722/LM3723/LM3724 microprocessor
supervisory circuits monitor the power supplies in
microprocessor and digital systems. They provide a
reset to the microprocessor during power-up, power-
down, brown-out conditions, and manual reset.
The LM3722/LM3723/LM3724 asserts a reset signal
whenever the supply decreases below the factory-
programmed reset threshold. Reset will be asserted
for at least 100ms even after V_CC rises above the
reset threshold.
The LM3722 has an active-low RESET push-pull
output. The LM3723 has an active-high RESET push-
pull output. The LM3724 has an active-low open-drain
RESET output.
Three standard reset voltage options are available,
suitable for monitoring 5V, 3.3V, and 2.5V supply
voltages. Additional reset voltages are also available;
contact Texas Instruments for details.
With a low supply current of only 6µA, the
LM3722/LM3723/LM3724 are ideal for use in portable
equipment. The LM3722/LM3723/LM3724 are
available in the 5-pin SOT-23 package.
Typical Application Circuits
VCC
PUSHBUTTON
SWITCH
VCC
LM3722
LM3723
RESET
MR *(RESET)
GND
VCC
PP
RESET
INPUT
GND
VCC
PUSHBUTTON
SWITCH
VCC
LM3724
MR
RESET
GND
VCC
RL
PP
RESET
INPUT
GND
Figure 1. Typical Application Circuit
Figure 2. Typical Application Circuit with R_L
Connection
1
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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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