Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O
05/24/99

ISSI reserves the right to make changes to its products at any time without notice in order to improve design and supply the best possible product. We assume no responsibility for any errors which
may appear in this publication. © Copyright 1999, Integrated Silicon Solution, Inc.

FEATURES

· High-speed access time: 10, 12, 15, 20, 25 ns

· Low active power: 400 mW (typical)

· Low standby power

-- 250

W (typical) CMOS standby

-- 55 mW (typical) TTL standby

· Fully static operation: no clock or refresh

required

· TTL compatible inputs and outputs

· Single 5V power supply

DESCRIPTION

The

ISSI

IS61C256AH is a very high-speed, low power,

32,768 word by 8-bit static RAMs. They are fabricated using

ISSI

's high-performance CMOS technology. This highly reli-

able process coupled with innovative circuit design tech-
niques, yields access times as fast as 10 ns maximum.

When

is HIGH (deselected), the device assumes a standby

mode at which the power dissipation can be reduced down to
250

W (typical) with CMOS input levels.

Easy memory expansion is provided by using an active LOW
Chip Enable (

) input and an active LOW Output Enable (

)

input. The active LOW Write Enable (

) controls both writing

and reading of the memory.

The IS61C256AH is pin compatible with other 32K x 8 SRAMs
and are available in 28-pin PDIP, SOJ, and TSOP (Type I)
packages.

IS61C256AH

32K x 8 HIGH-SPEED CMOS STATIC RAM

MAY 1999

FUNCTIONAL BLOCK DIAGRAM

A0-A14

32K X 8

MEMORY ARRAY

DECODER

COLUMN I/O

CONTROL

CIRCUIT

GND

VCC

I/O

DATA

CIRCUIT

I/O0-I/O7

ISSI

Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O

05/24/99

IS61C256AH

ISSI

A14

A12

I/O0

I/O1

I/O2

GND

VCC

A13

A11

A10

I/O7

I/O6

I/O5

I/O4

I/O3

PIN CONFIGURATION

28-Pin DIP and SOJ

PIN CONFIGURATION

28-Pin TSOP

PIN DESCRIPTIONS

A0-A14

Address Inputs

Chip Enable Input

Output Enable Input

Write Enable Input

I/O0-I/O7

Bidirectional Ports

Vcc

Power

GND

Ground

ABSOLUTE MAXIMUM RATINGS

(1)

Symbol

Parameter

Value

Unit

TERM

Terminal Voltage with Respect to GND

0.5 to +7.0

BIAS

Temperature Under Bias

55 to +125

STG

Storage Temperature

65 to +150

Power Dissipation

1.5

OUT

DC Output Current (LOW)

Note:
1. Stress greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause

permanent damage to the device. This is a stress rating only and functional operation of the
device at these or any other conditions above those indicated in the operational sections of
this specification is not implied. Exposure to absolute maximum rating conditions for extended
periods may affect reliability.

22
23
24
25
26
27
28
1
2
3
4
5
6
7

21
20
19
18
17
16
15
14
13
12
11
10

9
8

A11

A9
A8

A13

VCC

A14
A12

A7
A6
A5
A4
A3

A10
CE
I/O7
I/O6
I/O5
I/O4
I/O3
GND
I/O2
I/O1
I/O0
A0
A1
A2

TRUTH TABLE

Mode

I/O Operation Vcc Current

Not Selected

High-Z

, I

(Power-down)

Output Disabled H

High-Z

Read

OUT

Write

Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O
05/24/99

IS61C256AH

ISSI

POWER SUPPLY CHARACTERISTICS

(1)

(Over Operating Range)

-10

-12

-15

-20

-25

Symbol

Parameter

Test Conditions

Min. Max.

Unit

Vcc Dynamic Operating

= Max.,

= V

Com.

165

155

145

135

125

Supply Current

OUT

= 0 mA, f = f

MAX

Ind.

165

155

145

135

TTL Standby Current

= Max.,

Com.

(TTL Inputs)

= V

or V

Ind.

, f = 0

CMOS Standby

= Max.,

Com.

Current (CMOS Inputs)

0.2V,

Ind.

0.2V, or

0.2V, f = 0

Note:
1. At f = f

MAX

, address and data inputs are cycling at the maximum frequency, f = 0 means no input lines change.

OPERATING RANGE

Range

Ambient Temperature

Speed

Commercial

C to +70

-10, -12

-15, -20, -25

10%

Industrial

C to +85

-12

-15, -20, -25

10%

DC ELECTRICAL CHARACTERISTICS

(Over Operating Range)

Symbol Parameter

Test Conditions

Min.

Max.

Unit

Output HIGH Voltage

= Min., I

= 4.0 mA

2.4

Output LOW Voltage

= Min., I

= 8.0 mA

0.4

Input HIGH Voltage

2.2

+ 0.5

Input LOW Voltage

(1)

0.5

0.8

Input Leakage

GND

Com.

Ind.

Output Leakage

GND

OUT

Com.

Outputs Disabled

Ind.

Note:
1. V

= 3.0V for pulse width less than 10 ns.

CAPACITANCE

(1,2)

Symbol

Parameter

Conditions

Max.

Unit

Input Capacitance

= 0V

OUT

Output Capacitance

OUT

= 0V

Notes:
1. Tested initially and after any design or process changes that may affect these parameters.
2. Test conditions: T

= 25

C, f = 1 MHz, Vcc = 5.0V.

Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O

05/24/99

IS61C256AH

ISSI

READ CYCLE SWITCHING CHARACTERISTICS

(1)

(Over Operating Range)

-10

-12

-15

-20

-25

Symbol

Parameter

Min.

Max

Min. Max.

Unit

Read Cycle Time

Address Access Time

OHA

Output Hold Time

ACE

Access Time

DOE

Access Time

LZOE

(2)

to Low-Z Output

HZOE

(2)

to High-Z Output

LZCE

(2)

to Low-Z Output

HZCE

(2)

to High-Z Output

(3)

to Power-Up

(3)

to Power-Down

Notes:
1. Test conditions assume signal transition times of 5 ns or less, timing reference levels of 1.5V, input pulse levels of

0 to 3.0V and output loading specified in Figure 1.

2. Tested with the load in Figure 2. Transition is measured

500 mV from steady-state voltage. Not 100% tested.

3. Not 100% tested.

AC TEST CONDITIONS

Parameter

Unit

Input Pulse Level

0V to 3.0V

Input Rise and Fall Times

3 ns

Input and Output Timing

1.5V

and Reference Levels

Output Load

See Figures 1 and 2

AC TEST LOADS

Figure 1

Figure 2

480

5 pF

Including

jig and

scope

255

OUTPUT

480

30 pF

Including

jig and

scope

255

OUTPUT

Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O
05/24/99

IS61C256AH

ISSI

DATA VALID

READ1.eps

PREVIOUS DATA VALID

OHA

OUT

ADDRESS

OHA

DOE

LZOE

ACE

LZCE

HZOE

HIGH-Z

DATA VALID

CE_RD2.eps

ADDRESS

OUT

HZCE

Notes:
1.

is HIGH for a Read Cycle.

2. The device is continuously selected.

= V

3. Address is valid prior to or coincident with

LOW transitions.

READ CYCLE NO. 2

(1,3)

AC WAVEFORMS

READ CYCLE NO. 1

(1,2)

Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O

05/24/99

IS61C256AH

ISSI

WRITE CYCLE SWITCHING CHARACTERISTICS

(1,3)

(Over Operating Range)

-10

-12

-15

-20

-25

Symbol Parameter

Min.

Max

Min. Max.

Unit

Write Cycle Time

SCE

to Write End

Address Setup Time

to Write End

Address Hold

from Write End

Address Setup Time

PWE

Pulse Width (

LOW)

PWE

Pulse Width (

HIGH)

6.5

Data Setup to Write End

Data Hold from Write End

HZWE

(2)

LOW to High-Z Output

LZWE

(2)

HIGH to Low-Z Output

Notes:
1. Test conditions assume signal transition times of 3 ns or less, timing reference levels of 1.5V, input pulse levels of 0 to 3.0V and

output loading specified in Figure 1.

2. Tested with the load in Figure 2. Transition is measured

500 mV from steady-state voltage. Not 100% tested.

3. The internal write time is defined by the overlap of

LOW and

LOW. All signals must be in valid states to initiate a Write,

but any one can go inactive to terminate the Write. The Data Input Setup and Hold timing are referenced to the rising or falling
edge of the signal that terminates the write.

AC WAVEFORMS

WRITE CYCLE NO. 1 (

Controlled)

(1,2)

DATA UNDEFINED

VALID ADDRESS

SCE

PWE1

PWE2

HIGH-Z

HZWE

ADDRESS

OUT

DATA

VALID

LZWE

CE_WR1.eps

Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O
05/24/99

IS61C256AH

ISSI

DATA UNDEFINED

LOW

VALID ADDRESS

PWE1

HIGH-Z

HZWE

ADDRESS

OUT

DATA

VALID

LZWE

CE_WR2.eps

WRITE CYCLE NO. 2

(

is HIGH During Write Cycle)

(1,2)

WRITE CYCLE NO. 3

(

is LOW During Write Cycle)

(1)

DATA UNDEFINED

VALID ADDRESS

LOW

PWE2

HIGH-Z

HZWE

ADDRESS

OUT

DATA

VALID

LZWE

CE_WR3.eps

Notes:
1. The internal write time is defined by the overlap of

LOW and

LOW. All signals must be in valid states to initiate a Write,

but any one can go inactive to terminate the Write. The Data Input Setup and Hold timing are referenced to the rising or falling
edge of the signal that terminates the Write.

2. I/O will assume the High-Z state if

Integrated Silicon Solution, Inc. -- 1-800-379-4774

SR020-1O

05/24/99

IS61C256AH

ISSI

ORDERING INFORMATION: IS61C256AH

Commercial Range: 0

C to +70

Speed (ns)

Order Part Number

Package

IS61C256AH-10N

300-mil Plastic DIP

IS61C256AH-10J

300-mil Plastic SOJ

IS61C256AH-10T

TSOP (Type 1)

IS61C256AH-12N

300-mil Plastic DIP

IS61C256AH-12J

300-mil Plastic SOJ

IS61C256AH-12T

TSOP (Type 1)

IS61C256AH-15N

300-mil Plastic DIP

IS61C256AH-15J

300-mil Plastic SOJ

IS61C256AH-15T

TSOP (Type 1)

IS61C256AH-20N

300-mil Plastic DIP

IS61C256AH-20J

300-mil Plastic SOJ

IS61C256AH-20T

TSOP (Type 1)

IS61C256AH-25N

300-mil Plastic DIP

IS61C256AH-25J

300-mil Plastic SOJ

IS61C256AH-25T

TSOP (Type 1)

ORDERING INFORMATION: IS61C256AH

Industrial Range: 40

C to +85

Speed (ns)

Order Part Number

Package

IS61C256AH-12NI

300-mil Plastic DIP

IS61C256AH-12JI

300-mil Plastic SOJ

IS61C256AH-12TI

TSOP (Type 1)

IS61C256AH-15NI

300-mil Plastic DIP

IS61C256AH-15JI

300-mil Plastic SOJ

IS61C256AH-15TI

TSOP (Type 1)

IS61C256AH-20NI

300-mil Plastic DIP

IS61C256AH-20JI

300-mil Plastic SOJ

IS61C256AH-20TI

TSOP (Type 1)

IS61C256AH-25NI

300-mil Plastic DIP

IS61C256AH-25JI

300-mil Plastic SOJ

IS61C256AH-25TI

TSOP (Type 1)

ISSI

Integrated Silicon Solution, Inc.

2231 Lawson Lane

Santa Clara, CA 95054

Tel: 1-800-379-4774
Fax: (408) 588-0806

E-mail: sales@issi.com

www.issi.com

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