IMP18 1 2
P
OWER
M
ANAGEMENT
Low Power, 5V µP Reset
Key Features
x
Improved Dallas DS1812 replacement
— Over 50% lower maximum supply current
x
Low Supply Current
— 20µA maximum (5.5V)
x
Automatically restarts a microprocessor after
power failure
x
150ms reset delay after V
CC
returns to an
in-tolerance condition
x
Active HIGH power-up reset
x
Precision temperature-compensated voltage
reference and comparator
x
Eliminates external components
x
Low-cost TO-92 package
x
Compact surface mount SOT-23 package
x
Push-Pull output for minimum current drain
x
Operating temperature – 40°C to +85°C
– Active HIGH, Push-Pull Output
The IMP1812 supply voltage monitor is an improved, low-power
replacement for the Dallas Semiconductor DS1812. Maximum supply
current over temperature is a low 20µA, representing over 50 percent
lower power as compared to the DS1812.
The IMP1812 issues an active HIGH reset signal whenever the moni-
tored supply is out-of-tolerance. A precision reference and comparator
circuit monitor power supply (V
CC
) level. Tolerance level options are 5-,
10- and 15-percent. When an out-of-tolerance condition is detected, an
internal power-fail signal is generated which forces an active HIGH reset
signal. After V
CC
returns to an in-tolerance condition, the reset signal
remains active for 150ms to allow the power supply and system micro-
processor to stabilize.
The IMP1812 is designed with a push-pull output stage and operates
over the extended industrial temperature range. Devices are available in
compact surface mount SOT-23 packages and 3-lead TO-92 packages.
Other low power products in this family include the IMP1810/11/15/16/17,
IMP1233D and IMP1233M.
Family Selection Guide
Part
IMP1810
IMP1811
IMP1812
IMP1815
IMP1816
IMP1817
IMP1233D
IMP1233M
RESET Voltage RESET Time
(V)
(ms)
4.620, 4.370, 4.120
4.620, 4.350, 4.130
4.620, 4.350, 4.130
3.060, 2.880, 2.550
3.060, 2.880, 2.550
3.060, 2.880, 2.550
4.625, 4.375, 4.125
4.625, 4.375, 2.720
150
150
150
150
150
150
350
350
Output
Stage
Push-Pull
Open-Drain
Push-Pull
Push-Pull
Open-Drain
Push-Pull
Open-Drain
Open-Drain
RESET
Polarity
LOW
LOW
HIGH
LOW
LOW
HIGH
LOW
LOW
Applications
x
x
x
x
x
x
x
Set-top boxes
Cellular phones
PDAs
Energy management systems
Embedded control systems
Printers
Single board computers
Block Diagram
V
CC
1
VCC
Supply
Tolerance
Bias
Typical Application
IMP1812
IMP1812
+
–
Microprocessor
Delay
150ms
Typical
2
RESET
RESET
RESET
Reference
3
GND
©
1999 IMP, Inc.
GND
1812_02.eps
1812_01.eps
408-432-9100/www.impweb.com
1
A1PROS [ A1 PROS CO., LTD. ]
