Symbol

Parameter

Value

Unit

Ambient Operating Temperature

0 to 70

°C

–40 to 85

°C

Input or Output Voltages

–0.3 to 7

V

Supply Voltage

–0.3 to 7

V

Output Current

20

mA

Power Dissipation

1

W

Note: Stresses greater than those listed under ”Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress

rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of this

specification is not implied. Exposure to the absolute maximum ratings conditions for extended periods of time may affect reliability.

CAUTION: Negative undershoots below –0.3 volts are not allowed on any pin while in the Battery Back-up mode.

Table 2. Absolute Maximum Ratings

A1

A0

NC

A4

RST

WDI

A2

A3

IRQ/FT

A9

A10

A11

G

DQ7

NC

NC

NC

E

DQ6

DQ1

VSSQ

DQ3

VSS

DQ4

NC

A13

VCCQ

A12

A5

A14

VCC

A6

AI01625

M48T36

8

2

3

4

5

6

7

9

10

11

12

13

14

15

16

32

31

30

29

28

27

26

25

24

23

22

20

19

18

17

NC

DQ0

NC

NC

NC

NC

44

39

38

37

36

35

34

33

NC

A8

DQ2

21

DQ5

40

43

1

42

41

A7

W

Figure 2A. DIP Pin Connections

DESCRIPTION

The M48T36 TIMEKEEPER

™ RAM is a 32K x 8

non-volatile static RAM and real time clock. The

monolithic chip is available in a special package to

provide a highly integrated battery backed-up

memory and real time clock solution. The M48T36

is a non-volatile pin and function equivalent to any

JEDEC standard 32K x 8 SRAM. It also easily fits

into many ROM, EPROM, and EEPROM sockets,

providing the non-volatility of PROMs without any

requirement for special write timing or limitations on

the number of writes that can be performed.

The 44 pin 330mil SO provides sockets with gold

plated contacts at both ends for direct connection

to a separate SNAPHAT

™ housing containing the

battery and crystal. The unique design allows the

SNAPHAT battery package to be mounted on top

of the SO package after the completion of the

surface mount process.

Insertion of the SNAPHAT housing after reflow

prevents potential battery and crystal damage due

to the high temperatures required for device sur-

face-mounting. The SNAPHAT housing is keyed to

prevent reverse insertion.

The SO and battery packages are shipped sepa-

rately in plastic anti-static tubes. The SO package

is also available to ship in Tape & Reel form. For

the44leadSO, thebattery package (i.e.

SNAPHAT) part number is ”M4T44-BR12SH1”.

As Figure 3 shows, the static memory array and the

quartz controlled clock oscillator of the M48T36 are

integrated on one silicon chip. The two circuits are

interconnected at the upper eight memory locations

to provide user accessible BYTEWIDE

™ clock in-

formation in the bytes with addresses 7FF9h-

7FFFh. The clock locations contain the year,

month, date, day, hour, minute, and second in 24

hour BCD format. Corrections for 28, 29 (leap

year), 30, and 31 day months are made automat-

ically.

Warning: NC = Not Connected

2/17

M48T36