MK41T56

MKI41T56

512 bit (64b x8) Serial Access TIMEKEEPER

March 1999

1/15

COUNTERS for SECONDS, MINUTES,

HOURS, DAY, DATE, MONTH and YEARS

SOFTWARE CLOCK CALIBRATION

AUTOMATIC POWER-FAIL DETECT and

SWITCH CIRCUITRY

I

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

DESCRIPTION

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.

AI02304

OSCI

VCC

MK41T56

MKI41T56

VSS

SCL

OSCO

SDA

FT/OUT

VBAT

Figure 1. Logic Diagram

OSCI

Oscillator Input

OCSO

Oscillator Output

FT/OUT

Frequency Test / Output Driver

(Open Drain)

SDA

Serial Data Address Input / Output

SCL

Serial Clock

Battery Supply Voltage

Supply Voltage

Ground

Table 1. Signal Names

8

1

PSDIP8 (N)

0.4mm Frame

8

1

SO8 (S)

150mil Width