81C4256A-10 View Datasheet(PDF) - Fujitsu

Part Name

Description

MFG CO.

81C4256A-10

CMOS 256K x 4 BIT FAST PAGE MODE DYNAMIC RAM

Fujitsu 

MB81C4256A-60

MB81C4256A-70

MB81C4256A-80

MB81C4256A-10

Not Recommended for New Design

FUNCTIONAL TRUTH TABLE

Clock Input

Operation Mode

RAS CAS WE

OE

Standby

H

H

X

X

Read Cycle

L

L

H

L

Write Cycle

(Early Write)

L

L

L

X

Read-Modify-

Write Cycle

L

L

H→L L→H

RAS-onIy

Refresh Cycle

L

H

X

X

CAS-before RAS

Refresh Cycle

L

L

X

X

Hidden Refresh

Cycle

H→L

L

X

L

Address Input

Row Column

Data

Refresh

Input Output

Note

—

Valid

—

Valid

—

High-Z

—

—

Valid

Yes * tRCS ≥ tRCS (min)

Valid

Valid

Valid High-Z Yes * tWCS ≥ tWCS (min)

Valid

Valid

Valid

Valid

Yes *

Valid

—

—

High-Z Yes

—

—

—

High-Z

Yes tCSR ≥ tWCSR (min)

—

—

—

Valid

Yes

Previous data is

kept

Notes: X : “H”or”L”

* : It is impossible in Fast Page Mode.

8

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