1 of 5
041002
FEATURES
§ Automatically restarts microprocessor after
power failure
§ Maintains reset for 350 ms after V
CC
returns
to an in-tolerance condition
§ Accurate 5%, 10% or 15% microprocessor 5V
power supply monitoring
§ Reduces need for discrete components
§ Precision temperature-compensated voltage
reference and voltage sensor
§ Low-cost TO-92 package or surface mount
SOT-223 package
§ Internal 5 kW pull-up resistor
§ Compatible with Motorola 68XXX series and
HC16 Microprocessors
§ Operating temperature of -40°C to +85°C
PIN ASSIGNMENT
PIN DESCRIPTION
PIN 1
GROUND
PIN 2
RESET
PIN 3
V
CC
PIN 4
GROUND (SOT-223 ONLY)
DESCRIPTION
The DS1233D EconoReset uses a precision temperature-compensated reference and comparator circuit to
monitor the status of the power supply (V
CC
). When an out-of-tolerance condition is detected, an internal
power-fail signal is generated which forces reset to the active state. When V
CC
returns to an in-tolerance
condition, the reset signal is kept in the active state for approximately 350 ms to allow the power supply
and processor to stabilize.
OPERATION - POWER MONITOR
The DS1233D provides the functions of detecting out-of-tolerance power supply conditions and warning
a processor-based system of impending power failure. When V
CC
is detected as out of tolerance as
defined by the tolerance of the part selected, the
RST
signal is asserted. On power-up,
RST
is kept active
for approximately 350 ms after the power supply has reached the selected tolerance. This allows the
power supply and microprocessor to stabilize before
RST
is released.
DS1233D
5V EconoReset
www.maxim-ic.com
1 2 3
1 2 3
BOTTOM VIEW
TO-92 PACKAGE
See Mech.
Drawings Section
On Website
2
3
4
TOP VIEW
SOT-23 PACKAGE
See Mech.
Drawings Section
On Website
1
DALLAS
DS1233
Econo
Reset
DS1233D
4 of 5
ABSOLUTE MAXIMUM RATINGS*
Voltage on V
CC
Pin Relative to Ground
-0.5V to +7.0V
Voltage on I/O Relative to Ground
-0.5V to V
CC
+0.5V
Operating Temperature
-40°C to +85°C
Storage Temperature
-55°C to +125°C
Soldering Temperature
260°C for 10 seconds
* This is a stress rating only and functional operation of the device at these or any other conditions
above those indicated in the operation sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS
(-40
°
C to +85
°
C)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS NOTES
Supply Voltage
V
CC
1.2
5.0
5.5
V
1
DC ELECTRICAL CHARACTERISTICS (-40
°C to +85°C; V
DD
=5V
± 10%)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS NOTES
Low Level @
RST
V
OL
0.4
V
1
Output Current @ 0.4V
I
OL
+8
mA
2
Operating Current
I
CC
50
mA
V
CC
Trip Point 5%
V
CCTP1
4.5
4.625
4.74
V
1
V
CC
Trip Point 10%
V
CCTP2
4.25
4.375
4.49
V
1
V
CC
Trip Point 15%
V
CCTP3
4.0
4.125
4.24
V
1
Output Capacitance
C
OUT
10
pF
Internal Pull-Up Resistor
R
P
3.75
5
6.25
k
W
AC ELECTRICAL CHARACTERISTICS (-40
°C to +85°C; V
CC
=5V
± 10%)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS NOTES
Reset Active Time
t
RST
250
350
450
ms
V
CC
Detect to
RST
t
RPD
100
ns
V
CC
Slew Rate (4.75V - 4.00V)
t
F
300
ms
V
CC
Slew Rate (4.00V - 4.75V)
t
R
0
ns
V
CC
Detect to RST
t
RPU
250
350
450
ms
NOTES:
1. All voltages are referenced to ground.
2. A 1 k
W external resistor may be required for proper operation of the microprocessor reset control
circuit.
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