Global Mixed-mode Technology Inc.
G680/G681
Microprocessor Reset IC
Features
General Description
High ±2% Voltage Threshold Accuracy
The G680/G681 are microprocessor (µP) supervisory
circuits used to monitor the power supplies in µP and
digital systems. High- and Low- voltage thresholds can
be adjusted independently, allowing for wide hystere-
sis. Voltage detection thresholds are accurate to 2%.
Independently Adjustable High- and Low-
Voltage Thresholds
Fully Specified Over Temperature
Available in Three Output Configurations
Push-Pull RESET Output (G680L)
Push-Pull RESET Output (G680H)
These circuits perform a single function: they assert a
reset signal whenever the VCC supply voltage declines
below the low-voltage threshold, keeping it asserted
for at least 140ms after VCC has risen above the
high-voltage threshold.
Open-Drain RESET Output (G681L)
140ms min Power-On Reset Pulse Width
4µA Supply Current
Power Supply Transient Immunity
5-Pin SOT-23-5 Packages
The G681L has an open-drain output stage, while the
G680 have push-pull outputs. The G681L’s open-drain
RESET output requires a pull-up resistor that can be
connected to a voltage higher than VCC. The G680L
Applications
Computers
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.
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable / Battery-Powered Equipment
Automotive
The IC’s power supply is separate from the detector
inputs, allowing the G680/G681 to be powered from a
down-stream supply. Low supply current (4µA, typical)
makes the G680/G681 ideal for use in portable
equipment. The G680/G681 are available in 5 pin SOT
-23-5 packages.
Ordering Information
ORDER
NUMBER
G680LT1U
G680HT1U
G681LT1U
ORDER NUMBER
TEMP.
PACKAGE
RANGE
(Pb free)
G680LT1Uf
G680HT1Uf
G681LT1Uf
-40°C ~ +105°C
-40°C ~ +105°C
-40°C ~ +105°C
SOT-23-5
SOT-23-5
SOT-23-5
Note: T1: SOT-23-5
Pin Configuration
Typical Application Circuit
VCC
HTH
Vcc
1
5
4
VCC
VCC
LTH
RPULL-UP
*
2
3
GND
LTH
µP
G680/G681
SOT-23-5
G680/G681
RESET
RESET
(RESET)
HTH
INPUT
GND
GND
RESET(RESET)
*G681 ONLY
() is for G680H
TEL: 886-3-5788833
http://www.gmt.com.tw
Ver: 1.5
Jul 20, 2005
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