IMP1 233M
P
OWER
M
ANAGEMENT
Low Power, 5V/3.0V µP Reset
Key Features
N
Improved Dallas DS1233M replacement
— 60% lower maximum supply current
N
Low Supply Current
— 20µA maximum (5.5V)
— 15µA maximum (3.6V)
N
Automatically restarts a microprocessor after
power failure
N
350ms reset delay after V
CC
returns to an
in-tolerance condition
N
Active LOW power-up reset, 5kΩ internal pull-up
N
Precision temperature-compensated voltage
reference and comparator
N
Eliminates external components
N
Pin function compatible with the Motorola
MC33064, MC34064, MC33164 and MC34164
N
Motorola 68xxx and HC16 compatible
N
Low-cost TO-92 package
N
Compact surface mount SO-8 package
N
Operating temperature – 40°C to +85°C
– Active LOW, Open-Drain Output
– 350ms Reset Period
The IMP1233M supply voltage monitor is an improved, low-power
replacement for the Dallas Semiconductor DS1233M. Maximum supply
current over temperature is a low 20µA, representing 60 percent lower
power as compared to the DS1233M.
The IMP1233M issues an active LOW 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- and 10-percent for a 5V power supply. The tolerance is 15-percent for
the 3.3V, IMP1233M. When an out-of-tolerance condition is detected, an
internal power-fail signal is generated which forces an active LOW reset
signal. After V
CC
returns to an in-tolerance condition, the reset signal
remains active for 350ms to allow the power supply and system micro-
processor to stabilize.
The IMP1233M is designed with a open-drain output stage and operates
over the extended industrial temperature range. Devices are available in
the compact surface mount SO-8 package and a 3-lead TO-92 package.
Other low power products in this family include the IMP1810/11/12/15/
16/17 and IMP1233D.
Family Selection Guide
Part
IMP1810
IMP1811
IMP1812
IMP1815
IMP1816
IMP1817
IMP1233D
IMP1233M
RESET Voltage RESET Time
(V)
(ms)
4.620,
4.620,
4.620,
3.060,
3.060,
3.060,
4.625,
4.625,
4.370,
4.350,
4.350,
2.880,
2.880,
2.880,
4.375,
4.375,
4.120
4.130
4.130
2.550
2.550
2.550
4.125
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
N
N
N
N
N
N
N
Set-top boxes
Cellular phones
PDAs
Energy management systems
Embedded control systems
Printers
Single board computers
Block Diagram
V
CC
VCC
Supply
Tolerance
Bias
Typical Application
IMP1233M
+
–
Delay
350ms Typical
5.0k
9
IMP1233M
RESET
RESET
Microprocessor
RESET
Reference
GND
GND
1233M_02.eps
1233M_01.eps
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IMP1 233M
Absolute Maximum Ratings
Voltage on V
CC
. . . . . . . . . . . . . . . . . . . . . . . . –0.5V to 6.5V
Voltage on RESET . . . . . . . . . . . . . . . . . . . . . –0.5V to V
CC
+ 0.5V
Operating Temperature Range . . . . . . . . . . . –40°C to 85°C
Voltages measured with respect to ground.
These are stress ratings only and functional operation is not implied.
Soldering Temperature . . . . . . . . . . . . . . . . . . 260°C for 10 seconds
Storage Temperature . . . . . . . . . . . . . . . . . . . –55°C to 125°C
Electrical Characteristics
Unless otherwise noted, V
CC
= 1.2V to 5.5V and specifications are over the operating temperature range of – 40°C to +85°C.
All voltages are referenced to ground.
Parameter
Supply Voltage
Output Voltage
Output Current
Operating Current
Operating Current
V
CC
Trip Point (IMP1233M-5)
V
CC
Trip Point (IMP1233M-55)
V
CC
Trip Point (IMP1233M-3)
Voltage High Trip Level
IMP1233M-5
IMP1233M-55
Voltage Low Trip Level
IMP1233M-5
IMP1233M-55
Voltage High Trip Level
IMP1233M-3
Voltage Low Trip Level
IMP1233M-3
Internal Pull-Up Resistor
Output Capacitance
V
CC
Detect to RESET Low
V
CC
Slew Rate
(V
HTL
- V
LTL
)
V
CC
Slew Rate
(V
LTL
- V
HTL
)
V
CC
Detect to RESET High
Symbol
V
CC
V
OH
I
OL
I
CC
I
CC
V
CCTP
V
CCTP
V
CCTP
V
HTL
Conditions
I
OUT
< 500µA
Output = 0.4V, V
CC
≥
2.7V
V
CC
< 5.5V, RESET output open
V
CC
≤
3.6V, RESET output open
Min
1.2
V
CC
– 0.5V
+8
Typ
V
CC
– 0.1V
8
6
Max
5.5
Units
V
V
mA
20
15
4.49
4.75
2.8
4.75
µA
µA
V
V
V
V
4.25
4.5
2.64
4.375
4.625
2.72
V
LTL
4.00
V
V
HTL
V
LTL
R
P
C
OUT
t
RPD
t
F
t
R
t
RPU
t
R
= 5µs
300
0
200
350
2
3.5
5.0
3.14
2.48
7.5
10
10
V
V
kΩ
pF
µs
µs
ns
500
ms
Notes: 1. A 1k
Ω
external resistor maybe required in some applications for proper operation of the microprocessor reset control circuit.
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IMP1 233M
Application Information
Operation – Power Monitor
The IMP1233M detects out-of-tolerance power supply conditions.
It resets a processor during power-up and issues a reset to the
system processor when the monitored power supply voltage
is below the reset threshold (power-down). When an out-of-
tolerance V
CC
voltage is detected, the RESET signal is asserted. On
power-up, RESET is kept active (LOW) for approximately 350ms
after the power supply voltage has reached the selected tolerance.
This allows the power supply and microprocessor to stabilize
before RESET is released.
t
R
V
HTL
V
LTL
V
CCTP
V
CC
t
RPU
V
OH
RESET
1233M_05.eps
Figure 1. Timing Diagram: Power-Up
t
F
V
CC
V
HTL
V
CCTP
V
LTL
t
RPD
RESET
V
OL
1233M_06.eps
Figure 2. Timing Diagram: Power-Down
4
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