Global Mixed-mode Technology Inc.
G680/G681
Microprocessor Reset IC
Features
High
鹵
2% Voltage Threshold Accuracy
Independently Adjustable High- and Low-
Voltage Thresholds
General Description
The G680/G681 are microprocessor (碌P) supervisory
circuits used to monitor the power supplies in 碌P and
digital systems. High- and Low- voltage thresholds can
be adjusted independently, allowing for wide hystere-
sis. Voltage detection thresholds are accurate to 2%.
These circuits perform a single function: they assert a
reset signal whenever the V
CC
supply voltage declines
below the low-voltage threshold, keeping it asserted
for at least 140ms after V
CC
has risen above the
high-voltage threshold.
The G681L has an open-drain output stage, while the
G680 have push-pull outputs. The G681L鈥檚 open-drain
RESET output requires a pull-up resistor that can be
connected to a voltage higher than V
CC
. The G680L
have an active-low RESET output, while the G680H
has an active-high RESET output. The reset com-
parator is designed to ignore fast transients on thresh-
old input.
The IC鈥檚 power supply is separate from the detector
inputs, allowing the G680/G681 to be powered from a
down-stream supply. Low supply current (4碌A(chǔ), typical)
makes the G680/G681 ideal for use in portable
equipment. The G680/G681 are available in 5 pin SOT
23-5 packages.
Fully Specified Over Temperature
Available in Three Output Configurations
Push-Pull RESET Output (G680L)
Push-Pull RESET Output (G680H)
Open-Drain RESET Output (G681L)
140ms min Power-On Reset Pulse Width
4碌A(chǔ) Supply Current
Power Supply Transient Immunity
5-Pin SOT23-5 Packages
Applications
Computers
Controllers
Intelligent Instruments
Critical 碌P and 碌C Power Monitoring
Portable / Battery-Powered Equipment
Automotive
Ordering Information
PART
G680H(L)T1
G681LT1
TEMP. RANGE
-40擄C ~ +105擄C
-40擄C ~ +105擄C
PIN-PACKAGE
SOT23-5
SOT23-5
Pin Configuration
Typical Operating Circuit
V
CC
HTH 1
5
Vcc
V
CC
HTH
R
PULL-UP
*
V
CC
GND
2
G680/G681
G680/G681
LTH
RESET
(RESET)
GND
碌P
RESET
INPUT
GND
LTH 3
SOT23-5
() is for G680H
4
RESET(RESET)
*G681 ONLY
Ver: 03 Preliminary
Jan 25 2002
1
TEL: 886-3-5788833
http://www.gmt.com.tw
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