6-124

is the minimum write pulse. At the end of the write period, if

W rises before either select the outputs will enable reading

data just written. They will not disable until either select goes

high (TSHQZ).

If a series of consecutive write cycles are to be performed,

W may remain low until all desired locations are written. This

is an extension of Case 2.

Read-Modify-Write cycles and Read-Write-Read cycles can

be performed (extension of Case 1). In fact data may be

modified as many times as desired with E remaining low.

Burn-In Circuit

HM-6561/883

CERDIP

NOTES:

All resistors 47k

Ω±5%.

F0 = 100kHz

±10%.

F1 = F0

÷ 2, F2 = F1 ÷ 2, F3 = F2 ÷ 2 . . . F12 = F11 ÷ 2.

VCC = 5.5V

±0.5V.

VIH = 4.5V

±10%.

VIL = -0.2V to +0.4V.

C1 = 0.01

µF Min.

IF

OBSERVE

IGNORE

CASE 1

Both S1 and S2 = Low

Before W = Low

TWLQZ

TWLDV

TDVWH

TWLWH

CASE 2

W = Low Before Both

S1 and S2 = Low

TWLWH

TDVWH

TWLQZ

TWLDV

10

11

12

13

14

15

16

17

18

9

8

7

6

5

4

3

2

1

VCC

W

S1

DQ3

DQ2

DQ1

DQ0

A4

S2

A3

A2

A1

A0

A5

A6

GND

A7

E

C1

VCC

F6

F5

F4

F3

F8

F9

F10

F0

F7

F1

F0

F2

F2

F2

F2

F0

HM-6561/883