
Ver: 03 Preliminary 
Jan 25 2002 
TEL: 886-3-5788833 
http://www.gmt.com.tw 
1
G680/G681
Global Mixed-mode Technology Inc. 
Microprocessor Reset IC 
Features 
High 
±
2% Voltage Threshold Accuracy 
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) 
Open-Drain RESET Output (G681L)
 140ms min Power-On Reset Pulse Width 
 4μA Supply Current 
 Power Supply Transient Immunity 
 5-Pin SOT23-5 Packages
Applications 
 Computers 
 Controllers 
 Intelligent Instruments 
 Critical μP and μC Power Monitoring 
 Portable / Battery-Powered Equipment 
 Automotive
General Description 
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%. 
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’s 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’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 
PART 
G680H(L)T1 
G681LT1 
TEMP. RANGE 
-40°C ~ +105°C 
-40°C ~ +105°C  
PIN-PACKAGE 
SOT23-5 
SOT23-5 
Pin Configuration                     Typical Operating Circuit
  
Vcc
RESET(RESET)
SOT23-5
5
4
1
HTH
2
3
GND
LTH
G680/G681
() is for G680H
INPUT
GND
μP 
V
CC
GND
G680/G681
V
CC
R
PULL-UP
V
CC
*
*G681 ONLY
HTH
LTH
RESET
(RESET)
RESET