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M48Z128, M48Z128Y

Figure 3. Block Diagram

AI01196

INTERNAL

BATTERY

E

VCC

VSS

VOLTAGE SENSE

AND

SWITCHING

CIRCUITRY

131,072 x 8

SRAM ARRAY

A0-A16

DQ0-DQ7

W

G

POWER

E

The unique design allows the SNAPHAT battery

package to be mounted on top of the SOIC pack-

age after the completion of the surface mount pro-

cess. Insertion of the SNAPHAT housing after

reflow prevents potential battery damage due to

the high temperatures required for device surface-

mounting. The SNAPHAT housing is keyed to pre-

vent reverse insertion.

The SNAPHAT battery package is shipped sepa-

rately in plastic anti-static tubes or in Tape & Reel

form. The part number is ”M4Z28-BRxxSH1”.

The M48Z128/128Y also has its own Power-fail

Detect circuit. The control circuitry constantly mon-

itors the single 5V supply for an out of tolerance

write protects the SRAM, providing a high degree

of data security in the midst of unpredictable sys-

below approximately 3V, the control circuitry con-

nects the battery which maintains data until valid

power returns.

READ MODE

The M48Z128/128Y is in the Read Mode whenev-

er W (Write Enable) is high and E (Chip Enable) is

low. The device architecture allows ripple-through

access of data from eight of 1,048,576 locations in

the static storage array. Thus, the unique address

specified by the 17 Address Inputs defines which

one of the 131,072 bytes of data is to be accessed.

Valid data will be available at the Data I/O pins

address input signal is stable, providing that the E

and G (Output Enable) access times are also sat-

isfied. If the E and G access times are not met, val-

id data will be available after the later of Chip

state Data I/O signals is controlled by E and G. If

lines will be driven to an indeterminate state until

and G remain low, output data will remain valid for

minate until the next Address Access.