DS1232LPS-2+ Maxim Integrated Products, DS1232LPS-2+ Datasheet - Page 2

• Manufacturer Part Number: DS1232LPS-2+
• Description: IC MICRO MONITOR LOW PWR 8-SOIC
• Manufacturer: Maxim Integrated Products
• Series: MicroMonitor™r
• Type: Simple Reset/Power-On Resetr

Specifications of DS1232LPS-2+

• Number Of Voltages Monitored: 1
• Output: Open Drain, Push-Pull
• Reset: Active High/Active Low
• Reset Timeout: Adjustable/Selectable
• Voltage - Threshold: 4.37V, 4.62V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Monitored Voltage: 4.5 V to 5.5 V
• Undervoltage Threshold: 4.5 V or 4.25 V
• Overvoltage Threshold: 4.74 V or 4.49 V
• Manual Reset: Resettable
• Watchdog: Yes
• Battery Backup Switching: No
• Power-up Reset Delay (typ): 1000 ms
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4.5 V
• Supply Current (typ): 500 uA
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 70 C
• Chip Enable Signals: No
• Minimum Operating Temperature: 0 C
• Operating Supply Voltage: 5 V
• Output Type: Active High or Active Low or Open Drain
• Power Fail Detection: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The second function the DS1232 performs is pushbutton reset control. The DS1232 debounces the
pushbutton input and guarantees an active reset pulse width of 250 ms minimum. The third function is a
watchdog timer. The DS1232 has an internal timer that forces the reset signals to the active state if the
strobe input is not driven low prior to timeout. The watchdog timer function can be set to operate on
timeout settings of approximately 150 ms, 600 ms, and 1.2 seconds.
OPERATION - POWER MONITOR
The DS1232 detects out-of-tolerance power supply conditions and warns a processor-based system of
impending power failure. When V
comparator outputs the signals RST (Pin 5) and
and
and
signals for a microprocessor, as processing is stopped at the last possible moments of valid V
power-up, RST and
processor to stabilize.
OPERATION - PUSHBUTTON RESET
The DS1232 provides an input pin for direct connection to a pushbutton (Figure 2). The pushbutton reset
input requires an active low signal. Internally, this input is debounced and timed such that RST and
signals of at least 250 ms minimum are generated. The 250 ms delay starts as the pushbutton reset input is
released from low level.
OPERATION - WATCHDOG TIMER
A watchdog timer function forces RST and
stimulated for a predetermined time period. The time period is set by the TD input to be typically 150 ms
with TD connected to ground, 600 ms with TD left unconnected, and 1.2 seconds with TD connected to
V
If a high-to-low transition occurs on the
begins to timeout again. If the watchdog timer is allowed to timeout, then the RST and
driven to the active state for 250 ms minimum. The
address signals, data signals, and/or control signals. When the microprocessor is functioning normally,
these signals would, as a matter of routine, cause the watchdog to be reset prior to timeout. To guarantee
that the watchdog timer does not timeout, a high-to-low transition must occur at or less than the minimum
shown in Table 1. A typical circuit example is shown in Figure 3.
CC
. The watchdog timer starts timing out from the set time period as soon as RST and
RST
RST
signals become active as V
signals become active as V
RST
are kept active for a minimum of 250 ms to allow the power supply and
CC
CC
CC
falls below a preset level as defined by TOL (Pin 3), the V
falls below 4.75 volts. When TOL is connected to V
falls below 4.5 volts. The RST and
ST
input pin prior to timeout, the watchdog timer is reset and
RST
RST
2 of 7
signals to the active state when the
(Pin 6). When TOL is connected to ground, the RST
ST
input can be derived from microprocessor
RST
are excellent control
RST
RST
ST
DS1232/DS1232S
are inactive.
CC
input is not
signals are
, the RST
CC
. On
RST
CC