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M48Z128, M48Z128Y

POWER SUPPLY DECOUPLING

and UNDERSHOOT PROTECTION

switching, can produce voltage fluctuations, re-

can be reduced if capacitors are used to store en-

stored in the bypass capacitors will be released as

low going spikes are generated or energy will be

absorbed when overshoots occur. A ceramic by-

pass capacitor value of 0.1

µF (as shown in Figure

9) is recommended in order to provide the needed

filtering.

In addition to transients that are caused by normal

SRAM operation, power cycling can generate neg-

tive spikes can cause data corruption in the SRAM

while in battery backup mode. To protect from

these voltage spikes, it is recommended to con-

1N5817 is recommended for through hole and

MBRS120T3 is recommended for surface mount.

Figure 9. Supply Voltage Protection

AI02169

VCC

0.1

µF

DEVICE

VCC

VSS

Table 10. Write Mode AC Characteristics

2. If E goes low simultaneously with W going low after W going low, the outputs remain in the high impedance state.

Symbol

Parameter

M48Z128/M48Z128Y

Unit

-70

-85

-120

Min

Max

Min

Max

Min

Max

Write Cycle Time

70

85

120

ns

Address Valid to Write Enable Low

0

0

0

ns

Address Valid to Chip Enable Low

0

0

0

ns

Write Enable Pulse Width

55

65

85

ns

Chip Enable Low to Chip Enable High

55

75

100

ns

Write Enable High to Address Transition

5

5

5

ns

Chip Enable High to Address Transition

15

15

15

ns

Input Valid to Write Enable High

30

35

45

ns

Input Valid to Chip Enable High

30

35

45

ns

Write Enable High to Input Transition

0

0

0

ns

Chip Enable High to Input Transition

10

10

10

ns

(1, 2)

Write Enable Low to Output Hi-Z

25

30

40

ns

Address Valid to Write Enable High

65

75

100

ns

Address Valid to Chip Enable High

65

75

100

ns

(1, 2)

Write Enable High to Output Transition

5

5

5

ns