DS1236S-5N+ Maxim Integrated Products, DS1236S-5N+ Datasheet - Page 3

• Manufacturer Part Number: DS1236S-5N+
• Description: IC MICROMANAGER 5% 16-SOIC
• Manufacturer: Maxim Integrated Products
• Series: MicroManagerr
• Type: Battery Backup Circuitr

Specifications of DS1236S-5N+

• Number Of Voltages Monitored: 1
• Output: Open Drain, Push-Pull
• Reset: Active High/Active Low
• Reset Timeout: 25 ms Minimum
• Voltage - Threshold: 4.62V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

POWER MONITOR
The DS1236 employs a band gap voltage reference and a precision comparator to monitor the 5-volt
supply (V
RST and
5% operation option (DS1236-5) is set for 4.75 volts (4.62 typical). The RST and
excellent for microprocessor reset control, as processing is stopped at the last possible moment of in-
tolerance V
typical) after V
operation described above is obtained with the reset control pin (RC) connected to GND (NMOS mode).
Please review the reset control section for more information.
WATCHDOG TIMER
The DS1236 provides a watchdog timer function which forces the RST and
state when the strobe input (
ms typically with a maximum time-out of 600 ms. The watchdog time-out period begins as soon as RST
and
timer is reset and begins to time out again. The
watchdog timer does not time out, a high-to-low transition on
(minimum time-out) from a reset. If the watchdog timer is allowed to time out, the RST and
are driven to the active state for 25 ms minimum. The
address, data, and/or control signals. Under normal operating conditions, these signals would routinely
reset the watchdog timer prior to time-out. If the watchdog timer is not required, two methods have been
provided to disable it.
Permanently grounding the IN pin in the CMOS mode (RC=1) will disable the watchdog. In normal
operation with RC=1, the watchdog is disabled as soon as the IN pin is below V
falling edge on
power is between V
watchdog timer is not affected by the IN pin when in NMOS mode (RC=0).
If the
the
falls to V
PUSHBUTTON RESET
An input pin is provided on the DS1236 for direct connection to a pushbutton. The pushbutton reset input
requires an active low signal. Internally, this input is pulled high by a 10k resistor whenever V
greater than V
driven to the active state for 25 ms minimum. This 25 ms delay begins as the pushbutton is released from
a low level. A typical example of the power monitor, watchdog timer, and pushbutton reset connections
are shown in Figure 4. The PBRST input is disabled whenever the IN pin voltage level is less than V
and the reset control (RC) is tied high (CMOS mode). The
below V
RST
NMI
ST
RST
outputs are driven to the active state. The V
output will occur only at power-up, or when the
NMI
input open. Independent of the state of the RC pin, the watchdog is also disabled as soon as V
BAT
CCTP
are inactive. If a high-to-low transition occurs at the
CC
RST
CC
. Timing of the
signal is required to monitor supply voltages, the watchdog may also be disabled by leaving
) in microprocessor-based systems. When an out-of-tolerance condition occurs, the RST and
.
. On power-up, the RST and
BAT
outputs will become active as V
CCTP
ST
. The
will generate an
TP
is reached to allow the power supply and microprocessor to stabilize. Note: The
and V
PBRST
PBRST
ST
CCTP
) is not stimulated for a predetermined time period. This time period is 400
pin is also debounced and timed such that the RST and
-generated RST is illustrated in Figure 5.
, as an
NMI
when IN is below V
NMI
RST
CC
signals are held active for a minimum of 25 ms (100 ms
will be returned immediately after the
ST
3 of 19
CC
falls below 4.5 volts (4.37 typical). The V
trip point (V
input timing is shown in Figure 2. To guarantee the
ST
ST
PBRST
pin is strobed. As shown in the Figure 3, a
input can be derived from microprocessor
TP
ST
. This allows the processor to verify that
CCTP
ST
input is also disabled whenever V
input prior to time-out, the watchdog
) is set for 10% operation so that the
must occur at or less than 100 ms
RST
TP
. With IN grounded, an
signals to the active
RST
RST
ST
RST
CCTP
strobe. The
signals are
outputs are
outputs
DS1236
for the
CC
CC
CC
TP
is
is