M41T94_09 Datasheet, PDF (1/41 Pages) STMicroelectronics – Serial real-time clock with 44 bytes NVRAM and reset

M41T94
Serial real-time clock with 44 bytes NVRAM and reset
Features
■ Counters for tenths/hundredths of seconds,
seconds, minutes, hours, day, date, month,
year, and century
■ 32 KHz crystal oscillator integrating load
capacitance (12.5 pF) providing exceptional
oscillator stability and high crystal series
resistance operation
■ Serial peripheral interface (2 MHz SPI)
■ Ultralow battery supply current of 500 nA (max)
■ 2.7 to 5.5 V operating voltage
■ 2.5 to 5.5 V oscillator operating voltage
■ Battery low flag
■ Automatic switchover and deselect circuitry
■ 44 bytes of general purpose RAM
■ Programmable alarm and interrupt function
(valid even during battery backup mode)
■ Accurate programmable watchdog timer (from
62.5 ms to 128 s)
■ Microprocessor power-on reset
■ Choice of power-fail deselect voltages
(V_CC = 2.7 to 5.5 V):
– THS = V_SS; 2.55 V ≤ V_PFD ≤ 2.70 V
– THS = V_CC; 4.20 V ≤ V_PFD ≤ 4.50 V
■ Packaging includes a 28-lead SOIC and
SNAPHAT^® top (to be ordered separately) or
16-lead SOIC
■ 28-lead SOIC package provides direct
connection for a SNAPHAT^® top which
contains the battery and crystal
■ RoHS compliant
– Lead-free second level interconnect
16
1
SO16 (MQ)
SNAPHAT^® (SH)
battery & crystal
28
1
SOH28 (MH)
January 2009
Rev 6
1/41
www.st.com
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