DS1238A-5 Maxim Integrated Products, DS1238A-5 Datasheet - Page 2
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DS1238A-5
Manufacturer Part Number
DS1238A-5
Description
IC MICROMANAGER 5% 16-DIP
Manufacturer
Maxim Integrated Products
Series
MicroManagerr
Type
Battery Backup Circuitr
Specifications of DS1238A-5
Number Of Voltages Monitored
1
Output
Open Drain or Open Collector
Reset
Active High/Active Low
Reset Timeout
40 ms Minimum
Voltage - Threshold
4.62V
Operating Temperature
0°C ~ 70°C
Mounting Type
Through Hole
Package / Case
16-DIP (0.300", 7.62mm)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
debounce circuit connected to the
the active state if the strobe input is not driven low prior to watchdog timeout. Oscillator control pins
OSCSEL and OSCIN provide either external or internal clock timing for both the reset pulse width and
the watchdog timeout period. The Watchdog Status and Reset Voltage Threshold are provided via
and
PIN DESCRIPTION
POWER MONITOR
The DS1238A employs a bandgap voltage reference and a precision comparator to monitor the 5-volt
supply (V
RST, and
so that the
The V
moment of in-tolerance V
However, the RST and
reached to allow the power supply and microprocessor to stabilize.
RST
PIN NAME
V
V
V
PF
OSCIN
OSCSEL
IN
RST
ST
RVT
NMI
CEO
CEI
WDS
RST
BAT
CCO
CC
RVT
signals are excellent for microprocessor reset control, as processing is stopped at the last possible
CCTP
, respectively. A block diagram of the DS1238A is shown in NO TAG.
CC
RST
for the 5% operation option (DS1238A-5) is set for 4.75 volts (4.62 typical). The RST and
RVT
) in microprocessor-based systems. When an out-of-tolerance condition occurs, the
outputs are driven to the active state. The V
, RST and
Power-fail indicator, active high, used for external power switching as shown in NO
Active high reset output.
DESCRIPTION
+3V battery input provides nonvolatile operation of control functions.
V
+5V primary power input.
TAG.
Reset Voltage Threshold. Indicates that V
Oscillator input or timing capacitor. See NO TAG.
Oscillator Select. Selects internal or external clock functions. See NO TAG.
Early warning power-fail input. This voltage sense point can be tied (via resistor
divider) to a user-selected voltage.
Non-maskable interrupt. Used in conjunction with the IN pin to indicate an impending
power failure.
Strobe input. A high-to-low transition will reset the watchdog timer, indicating that
software is still in control.
Chip enable output. Used with nonvolatile SRAM applications.
Chip enable input.
Watchdog Status. Indicates that a watchdog timeout has occurred.
Active low reset output.
CC
output for nonvolatile SRAM applications.
RST
CC
RST
. On power-up,
signals remain active for a minimum of 50 ms (100 ms typical) after V
outputs will become active as V
RST
pin. An internal watchdog timer can also force the reset outputs to
RVT
2 of 13
will become inactive as soon as V
CC
CC
is below the reset voltage threshold.
trip point (V
CC
falls below 4.5 volts (4.37 typical).
CCTP
) is set for 10% operation
CC
rises above V
DS1238A
CCTP
RVT
WDS
CCTP
is
,
.