DS1238S/T&R Maxim Integrated, DS1238S/T&R Datasheet - Page 3

• Manufacturer Part Number: DS1238S/T&R
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: DS1238r

Specifications of DS1238S/T&R

• Number Of Voltages Monitored: 1
• Monitored Voltage: 5 V
• Undervoltage Threshold: 4.25 V
• Overvoltage Threshold: 4.5 V
• Output Type: Active High, Active Low
• Manual Reset: Resettable
• Watchdog: Watchdog
• Battery Backup Switching: Backup
• Power-up Reset Delay (typ): 150 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-16 Wide
• Chip Enable Signals: Yes
• Minimum Operating Temperature: 0 C
• Power Fail Detection: Yes
• Supply Current (typ): 4000 uA
• Supply Voltage - Min: 4.5 V

DS1238
DS1238 FUNCTIONAL BLOCK DIAGRAM Figure 1
WATCHDOG TIMER
The DS1238 provides a watchdog timer function which forces the
, RST, and
signals to the
WDS
RST
active state when the strobe input (
) is not stimulated for a predetermined time period. This time period
ST
is described below in Table 1. The watchdog timeout period begins as soon as RST and
are inactive.
RST
If a high-to-low transition occurs at the
input prior to timeout, the watchdog timer is reset and begins
ST
to time out again. The
input timing is shown in Figure 2. In order to guarantee that the watchdog timer
ST
does not time out, a high-to-low transition on
must occur at or less than the minimum timeout of the
ST
watchdog as described in the AC Electrical Characteristics. If the watchdog timer is allowed to time out,
the
, RST, and
outputs are driven to the active state.
is a latched signal which indicates
WDS
RST
WDS
the watchdog status, and is activated as soon as the watchdog timer completes a full period as outlined in
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