LTC1232
Microprocessor
Supervisory Circuits
FEATURES
DESCRIPTIO
Guaranteed Reset Assertion at V = 1V The LTC 1232 provides power supply monitoring,
CC
8-Pin SO Plastic Package watchdog timing and external reset for microprocessor
2.0mA Maximum Supply Current systems. A precise internal voltage reference and
4.62V/4.37V Precision Voltage Monitor comparator circuit monitor the power supply line. When
Power OK/Reset Time Delay: 600ms an out-of-tolerance condition occurs, the reset outputs
Minimum External Component Count are forced to active states. The RST output is guaranteed
Superior Upgrade for DS1232 to remain logic low even with V as low as 1V.
CC
The LTC1232 has an internal watchdog timer which forces
U
the reset outputs to active states when the Strobe input is
APPLICATIO S
not forced low prior to a preset time-out period. The
Critical P Power Monitoring
watchdog timing can be set to operate on time-out periods
Intelligent Instruments
of typically 150ms, 600ms or 1.2 seconds.
Computers and Controllers
The LTC1232 performs push-button reset control.
Automotive Systems
The LTC1232 debounces the push-button input
and guarantees an active reset pulse width of 250ms
minimum.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
RST Output Voltage vs
Supply Voltage
5
5V DC
4
MPU
PB RST V
CC
(e.g. 6805)
100k
3
5V DC TD ST
I/O LINE
LTC1232
TOL RST
RESET 2
GND RST
1
LTC1232 TA01
0
0 1 2 3 4 5
SUPPLY VOLTAGE (V)
LTC1232 TA02
sn1232 1232fas
1
RST OUTPUT VOLTAGE (V)
U
ULTC1232
UUW
ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO
(Note 1, 2 and 3)
TOP VIEW
ORDER
Terminal Voltage
PB RST 1 8 V
CC PART NUMBER
V .......................................................0.3V to 7.0V
CC
TD 2 7 ST
ST and RST ..........................................0.3V to 7.0V
LTC1232CN8
TOL 3 RST
6
All Other Inputs and Outputs ...... 0.3V to V +0.3V
CC
GND 4 5 RST
Power Dissipation.............................................. 500mW
N8 PACKAGE
Operating Temperature Range
8-LEAD PDIP
LTC1232C ............................................... 0C to 70C
T = 100C, = 130C/W
JMAX
JA
LTC1232I ........................................... 40C to 85C
TOP VIEW ORDER
Storage Temperature Range ................. 65C to 150C
PART NUMBER
PB RST 1 8 V
CC
Lead Temperature (Soldering, 10 sec).................. 300C
TD 2 7 ST
LTC1232CS8
TOL 3 6 RST
LTC1232IS8
GND 4 5 RST
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
1232
T = 100C, = 180C/W
JMAX
JA
1232I
Consult LTC Marketing for parts specified with wider operating tempera-
ture ranges.
PRODUCT SELECTIO GUIDE
POWER RAM CONDITIONAL
WATCHDOG BATTERY FAIL WRITE PUSH-BUTTON BATTERY
PINS RESET TIMER BACKUP WARNING PROTECT RESET BACKUP
LTC1232 8 X X X
LTC690 8 X X X X
LTC691 16 X XXXX
LTC694 8 X X X X
LTC695 16 X XXXX
LTC699 8 X X
LTC1235 16 X XXXX X X
sn1232 1232fas
2
U
U WWW