DS1312S-2 Maxim Integrated Products, DS1312S-2 Datasheet - Page 3

• Manufacturer Part Number: DS1312S-2
• Description: IC CTRLR NV W/BATT MOD 8-SOIC
• Manufacturer: Maxim Integrated Products

Specifications of DS1312S-2

• Controller Type: Nonvolatile RAM
• Voltage - Supply: 4.75 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: DS1312S2

NOTE: The DS1312 cannot constantly monitor an attached battery because such monitoring would
drastically reduce the life of the battery. As a result, the DS1312 only tests the battery for one second out
of every 24 hours and does not monitor the battery in any way between tests. If a good battery (one that
has not been previously flagged with
immediately sense the removal and may not activate
is then reattached to the DS1312, the battery may not be tested until the next scheduled test.
NOTE: Battery monitoring is only a useful technique when testing can be done regularly over the entire
life of a lithium battery. Because the DS1312 only performs battery monitoring when V
systems which are powered-down for excessively long periods can completely drain their lithium cells
without receiving any advanced warning. To prevent such an occurrence, systems using the DS1312
battery monitoring feature should be powered–up periodically (at least once every few months) in order
to perform battery testing. Furthermore, anytime
data integrity should be checked via checksum or other technique.
POWER MONITORING
DS1312S and DS1312E varieties have an additional reset pin. These varieties detect out-of-tolerance
power supply conditions and warn a processor-based system of impending power failure. When V
below the trip point level defined by the TOL pin (V
GND or in the range of 4.5 to 4.25 volts (10% tolerance) when TOL is connected to V
for 200 ms nominal (t
power-on transients and to allow t
FRESHNESS SEAL MODE
When the battery is first attached to the DS1312 without V
immediately provide battery-backup power on V
leave Freshness Seal Mode. This mode allows a battery to be attached during manufacturing but not used
until after the system has been activated for the first time. As a result, no battery energy is drained during
storage and shipping.
RST
RST
. Reset occurs in the range of 4.75 to 4.5 volts (5% tolerance) when the TOL pin is connected to
also serves as a power-on reset during power-up. After V
RPU
). This reset period is sufficiently long to prevent system operation during
REC
to expire.
BW
) is removed between battery tests, the DS1312 may not
RST
BW
3 of 11
CCO
has an open-drain output driver.
BW
CCTP
is activated on the first battery test after a power-up,
. Only after V
), the V
until the next scheduled battery test. If a battery
CCI
CC
CCI
exceeds V
power applied, the device does not
CCI
comparator activates the reset signal
exceeds V
CCTP
,
RST
CCTP
CCO
will be held active
will the DS1312
.
CC
is nominal,
CCI
falls