MK41T56 Datasheet, PDF (1/15 Pages) STMicroelectronics – 512 bit 64b x8 Serial Access TIMEKEEPER SRAM

MK41T56
MKI41T56
512 bit (64b x8) Serial Access TIMEKEEPER^® SRAM
COUNTERS for SECONDS, MINUTES,
HOURS, DAY, DATE, MONTH and YEARS
SOFTWARE CLOCK CALIBRATION
AUTOMATIC POWER-FAIL DETECT and
SWITCH CIRCUITRY
I²C BUS COMPATIBLE
56 BYTES of GENERAL PURPOSE RAM
ULTRA-LOW BATTERY SUPPLY CURRENT of
500nA
OPERATING TEMPERATURE:
– MK41T56: 0 to 70°C
– MKI41T56: –40 to 85°C
AUTOMATIC LEAP YEAR COMPENSATION
8
1
PSDIP8 (N)
0.4mm Frame
8
1
SO8 (S)
150mil Width
DESCRIPTION
The MK41T56 TIMEKEEPER^® is a low power 512
bit static CMOS RAM organized as 64 words by 8
bits. A built-in 32.768 kHz oscillator (external crystal
controlled) and the first 8 bytes of the RAM are used
for the clock/calendar function and are configured
in binary coded decimal (BCD) format. Addresses
and data are transferred serially via a two-line
bi-directional bus. The built-in address register is
incremented automatically after each write or read
data byte. The MK41T56 clock has a built-in power
sense circuit which detects power failures and
automatically switches to the battery supply during
power failures. The energy needed to sustain the
RAM and clock operations can be supplied from a
small lithium button cell.
Table 1. Signal Names
OSCI
Oscillator Input
OCSO
Oscillator Output
FT/OUT
Frequency Test / Output Driver
(Open Drain)
SDA
Serial Data Address Input / Output
SCL
Serial Clock
V_BAT
VCC
V_SS
Battery Supply Voltage
Supply Voltage
Ground
March 1999
Figure 1. Logic Diagram
VCC VBAT
OSCI
SCL
MK41T56
MKI41T56
VSS
OSCO
SDA
FT/OUT
AI02304
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