Rainbow Electronics W24256 User Manual

Preliminary W24256

R

32K × 8 CMOS STATIC RAM

GENERAL DESCRIPTION

The W24256 is a normal speed, very low power CMOS static RAM organized as 32768 × 8 bits that
operates on a single 5-volt power supply. This device is manufactured using Winbond's high
performance CMOS technology.

FEATURES

•

Low power consumption:

•

Access time: 70 nS (max.)

•

Active :300 mW

Standby :250 µW

•

Single 5V power supply

•

Fully static operation

•

All inputs and outputs directly TTL compatible

•

Three-state outputs

•

Battery back-up operation capability

•

Data retention voltage: 2V (min.)

•

Packaged in 28-pin 600 mil DIP, 330 mil SOP
and standard type one TSOP (8 mm × 13.4
mm)

PIN CONFIGURATIONS

1

A14
A12

2

A7

3

A6

4

A5

5

A4

6

28-pin

7

DIP

8

9

10

11

12

13

14

1
2
3
4
5
6

28-pin

7

TSOP

8
9
10
11
12
13
14

WE
V
A14
A12

A11

A13

A3

A2

A1

A0

I/O1

I/O2

I/O3
V

SS

OE

A9
A8

DD

A7
A6
A5
A4
A3

BLOCK DIAGRAM

CLK GEN.

A12

A14

A2

WE
CS
OE

A3

A4

A5

A6

A7

A13

I/O1

I/O8

28

V

DD

27

WE

26

A13

25

A8

24

A9

23

A11

22

OE

21

A10

20

CS

I/O8

19

I/O7

18

I/O6

17

I/O5

16

I/O4

15

R
O

W

D
E
C
O
D
E

DATA
CNTRL.

CLK
GEN.

PRECHARGE CKT.

CORE CELL ARRAY

512 ROWS

64 X 8 COLUMNS

I/O CKT.

COLUMN DECODER

A10 A1 A0A8A9

A11

PIN DESCRIPTION

A10

28
27

CS

26

I/O8

25

I/O7

24

I/O6

23

I/O5

22

I/O4

21

SS

V

20

I/O3

19

I/O2

18

I/O1

17

A0
A1

16

A2

15

SYMBOL DESCRIPTION

A0−A14

I/O1−I/O8

CS

WE

OE

Address Inputs
Data Inputs/Outputs
Chip Select Input
Write Enable Input
Output Enable Input

VDD Power Supply
VSS Ground

Publication Release Date: October 1999

- 1 - Revision A1

Preliminary W24256

CS OE WE

TRUTH TABLE

V

MODE

I/O1

−

I/O8

H X X Not Selected High Z ISB, ISB1

L H H Output Disable High Z IDD
L L H Read Data Out IDD
L X L Write Data In IDD

DC CHARACTERISTICS

Absolute Maximum Ratings

PARAMETER RATING UNIT

Supply Voltage to VSS Potential -0.5 to +7.0 V
Input/Output to V
Allowable Power Dissipation 1.0 W
Storage Temperature -65 to +150
Operating Temperature 0 to 70

Note: Exposure to conditions beyond those listed under Absolute Maximum Ratings may adversely affect the life and reliability
of the device.

SS

Potential -0.5 to VDD +0.5 V

DD CURRENT

°

C

°C

Operating Characteristics

DD = 5V

(V

Input Low Voltage V
Input High Voltage V
Input Leakage Current I
Output Leakage Current I

Output Low Voltage V
Output High Voltage V
Operating Power
Supply Current
Standby Power Supply

Current

Note: Typical parameter is measured under ambient temperature TA = 25° C and VDD = 5V.

10%; VSS = 0V; TA = 0° C to 70° C)

±

PARAMETER SYM.

I
LL - - 50

TEST CONDITIONS MIN. TYP.* MAX. UNIT

IL

IH

LI

VIN = VSS to VDD -5 - +5

LO

VI/O = VSS to VDD,
(min.) or

WE

= V

OL IOL

OH IOH

DD

I

= +2.1 mA - - 0.4 V

= -1.0 mA 2.4 - - V

CS

= VIL (max.), I/O = 0 mA ,

- -0.5 - +0.8 V

- +2.2 - VDD +1 V

-5 - +5

IH

OE

= VIH (min.) or

IL

(max.)

CS

= V

- - 60 mA

Cycle = min , Duty = 100 %

I

SB

CS

IH

(min.), Cycle = min.

= V

- - 3 mA

Duty = 100%

SB1

CS ≥

V

DD

-0.2V

L - - 100

µ

A

µ

A

µ

A

µ

A

- 2 -

CAPACITANCE

(VDD = 5V, TA = 25° C, f = 1 MHz)

PARAMETER SYM. CONDITIONS MAX. UNIT

Input Capacitance CIN V
Input/Output Capacitance C

Note: These parameters are sampled but not 100% tested.

I/O

V

IN

= 0V 6 pF

OUT

= 0V 8 pF

Preliminary W24256

AC CHARACTERISTICS

AC Test Conditions

PARAMETER CONDITIONS

Input Pulse Levels 0V to 3.0V
Input Rise and Fall Times 5 nS
Input and Output Timing Reference Level 1.5V
Output Load See the drawing below

AC TEST LOADS AND WAVEFORM

1 TTL

OUTPUT

100 pF
Including
Jig and
Scope

3.0V

0V

5 nS

OUTPUT

(For T T T T T T )

CLZ, OLZ,

90%
10%

90%

10%

CHZ,

5 nS

OHZ, WHZ, OW

1 TTL

5 pF
Including
Jig and
Scope

Publication Release Date: October 1999

- 3 - Revision A1