DS1236 Datasheet, PDF (1/19 Pages) Dallas Semiconductor – MicroManager Chip

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DS1236
MicroManager Chip
FEATURES
Holds microprocessor in check during power
transients
Halts and restarts an out-of-control
microprocessor
Monitors pushbutton for external override
Warns microprocessor of an impending power
failure
Converts CMOS SRAM into nonvolatile
memory
Unconditionally write-protects memory when
power supply is out of tolerance
Consumes less than 100 nA of battery current
at 25°C
Controls external power switch for high
current applications
Accurate 10% power supply monitoring
Optional 5% power supply monitoring
designated DS1236-5
Provides orderly shutdown in nonvolatile
microprocessor applications
Supplies necessary control for low-power
“stop mode” in battery operated hand-held
applications
Standard 16-pin DIP or space-saving 16-pin
SOIC
Optional industrial temperature range -40°C
to +85°C
PIN ASSIGNMENT
VBAT 1 16 RST
VCCO 2 15 RST
VCC 3
GND 4
PF 5
PF 6
WC/SC 7
RC 8
14 PBRST
13 CEI
VBAT
VCCO
12 CEO
VCC
11 ST
10 NMI
GND
PF
PF
9 IN
WC/SC
RCI
1 16
2 15
3 14
4 13
5 12
6 11
7 10
8
9
RST
RST
PBRST
CEI
CEO
ST
NMI
IN
16-Pin DIP (300-mil)
See Mech. Drawings Section
16-Pin SOIC (300-mil)
See Mech. Drawings Section
PIN DESCRIPTION
V_BAT
V_CCO
V_CC
GND
- +3-Volt Battery Input
- Switched SRAM Supply Output
- +5-Volt Power Supply Input
- Ground
PF
- Power-Fail (Active High)
PF
- Power-Fail (Active Low)
WC/ SC
- Wake-Up Control (Sleep)
RC
- Reset Control
IN
- Early Warning Input
NMI
- Non-Maskable Interrupt
ST
- Strobe Input
CEO
- Chip Enable Output
CEI
- Chip Enable Input
PBRST
- Pushbutton Reset Input
RST
- Reset Output (Active Low)
RST
- Reset Output (Active High)
DESCRIPTION
The DS1236 MicroManager Chip provides all the necessary functions for power supply monitoring, reset
control, and memory backup in microprocessor-based systems. A precise internal voltage reference and
comparator circuit monitor power supply status. When an out-of-tolerance condition occurs, the
microprocessor reset and power-fail outputs are forced active, and static RAM control unconditionally
write protects external memory. The DS1236 also provides early warning detection of a user-defined
threshold by driving a non-maskable interrupt. External reset control is provided by a pushbutton reset
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