AS5SS256K18DQ-8/XT - Austin Semiconductor, Inc.

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

1

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

FEATURES

• Fast access times: 8, 10, and 15ns

• Fast clock speed: 113, 100, and 66 MHz

• Fast clock and OE\ access times

• Single +3.3V +0.3V/-0.165V power supply (VDD)

• SNOOZE MODE for reduced-power standby

• Common data inputs and data outputs

• Individual BYTE WR TIE control and GLOBAL WRITE

• Three chip enables for simple depth expansion and address

pipelining

• Clock-controlled and registered addresses, data I/Os and

control signals

• Interally self-timed WRITE cycle

• Burst control pin (interleaved or linear burst)

• Automatic power-down

• Low capacitive bus loading

• Operating Temperature Ranges:

- Military -55oC to +125oC

- Industrial -40oC to +85oC

OPTIONS MARKING

• Timing

7.5ns/8ns/113 MHz -8*

8.5ns/10ns/100 MHz -9

10ns/15ns/66 MHz -10

• Packages

100-pin TQFP DQ No. 1001

• Operating Temperature Ranges:

- Military -55oC to +125oCIT

- Industrial -45oC to +85oCXT

*available as IT only.

256K x 18 SSRAM

Synchronous Burst SRAM,

Flow-Through

PIN ASSIGNMENT

(Top View)

100-pin TQFP

For more products and information

please visit our web site at

www.austinsemiconductor.com

SA

CE\

CE2

NC

bwB\

BWa\

CE2\

V

DD

V

SS

CLK

GW\

BWE\

OE\

ADSC\

ADSP\

ADV\

SA

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

80

79

78

77

76

75

74

73

72

71

70

69

68

67

66

65

64

63

62

61

60

59

58

57

56

55

54

53

52

51

31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81

NC

VDDQ

VSS

NC

DQb

VSS

VDDQ

DQb

VSS

VDD

NC

VSS

DQb

VDDQ

VSS

DQb

DQPb

NC

VSS

VDDQ

NC

SA

NC

VDDQ

VSS

NC

DQPa

DQa

VSS

VDDQ

DQa

VSS

NC

VDD

ZZ

DQa

VDDQ

VSS

DQa

NC

VSS

VDDQ

NC

MODE

SA

SA1

SA0

DNU

V

SS

V

DD

NF**

SA

GENERAL DESCRIPTION

The Austin Semiconductor , Inc. Synchronous Burst SRAM family

employs high-speed, low power CMOS designs that are fabricated us-

ing an advanced CMOS process.

ASI’ s 4Mb Synchronous Burst SRAMs integrate a 256K x 18, SRAM

core with advanced synchronous peripheral circuitry and a 2-bit burst

counter . All synchronous inputs pass through registers controlled by a

positive-edge-triggered single clock input (CLK). The synchronous

inputs include all addresses, all data inputs, active LOW chip enable

(CE\), two additional chip enables for easy depth expansion (CE2\,

CE2), burst control inputs (ADSC\, ADSP\, ADV\), byte write enables

(BWx\) and global write (GW\).

Asynchronous inputs include the output enable (OE\), clock (CLK)

and snooze enable (ZZ). There is also a burst mode input (MODE) that

selects between interleaved and linear burst modes. The data-out (Q),

enabled by OE\, is also asynchronous. WRITE cycles can be from one

to two bytes wide, as controlled by the write control inputs.

Burst operation can be initiated with either address status processor

(ADSP\) or address status controller (ADSC\) inputs. Subsequent burst

addresses can be internally generated as controlled by the burst ad-

vance input (ADV\).

Address and write control are registered on-chip to simplify WRITE

cycles. This allows self-timed WRITE cycles. Individual byte enables

allow individual bytes to be written. During WRITE cycles on this x18

device BWa\ controls DQa pins and DQPa; BWb\ controls DQb pins

and DQPb. GW\ LOW causes all bytes to be written. Parity bits are

available on this device.

ASI’s 4Mb Synchronous Burst SRAMs operate from a +3.3V VDD

power supply , and all inputs and outputs are TTL-compatible. The de-

vice is ideally suited for 486, Pentium®, and PowerPC systems and

those systems that benefit from a wide synchronous data bus.

**pins 42,43 reserved for future address expansion for 8Mb, 16Mb densities.

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

2

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

PIN DESCRIPTIONS

PIN NUMBERS SYM TYPE DESCRIPTION

37, 36, 32-35, 44-50,

80-82, 99, 100 SA0, SA1,

SA Input Synchronous Address Inputs: These inputs are registered and must meet the setup and

hold times around the rising edge of CLK.

93, 94 BWa\

BWb\ Input Synchronous Byte Write Enables: These active LOW inputs allow individual bytes to be

written and must meet the setup and hold times around the rising edge of CLK. A byte

write enables is LOW for a WRITE cycle and HIGH for a READ cycle. BWa\ controls DQa

pins and DQPa; BWb\ controls DQb pins and DQPb.

87 BWE\ Input Byte Write Enable: This active LOW input permits BYTE WRITE operations and must meet

the setup and hold times around the rising edge of CLK.

88 GW\ Input Global Write: This active LOW input allows a full 18-bit WRITE to occur independent of the

BWE\ and BWx\ lines and must meet the setup and hold times around the rising edge of

CLK.

89 CLK Input Clock: This signal registers the addresses, data, chip enables, byte write enables and burst

control inputs on its rising edge. All synchronous inputs must meet setup and hold times

around the clock’s risin

g

ed

g

e.

98 CE\ Input Synchronous Chip Enable: This active LOW input is used to enable the device and

Conditions the internal use of ADSP\. CE\ is sampled only when a new external address is

loaded.

92 CE2\ Input Synchronous Chip Enable: This active LOW input is used to enable the device and is

sampled only when a new external address is loaded.

97 CE2 Input Synchronous Chip Enable: This active HIGH input is used to enable the device and is

sampled only when a new external address is loaded.

86 OE\ Input Output Enable: This active LOW, asynchronous input enables the data I/O output drivers.

83 ADV\ Input Synchronous Address Advance: This active LOW input is used to advance the internal

burst counter, controlling burst access after the external address is loaded. A HIGH on this

pin effectively causes wait states to be generated (no address advance). To ensure use of

correct address during WRITE cycle, ADV\ must be HIGH at the rising edge of the first

clock after an ADSP\ cycle is initiated.

84 ADSP\ Input Synchronous Address Status Processor: This active LOW input interrupts any ongoing

burst, causing a new external address to be registered. A READ is performed using the

new address, independent of the byte write enables and ADSC\, but dependent upon CE\,

CE2, and CE2\. ADSP\ is ignored if CE\ is HIGH. Power-down state is entered if CE2 if

LOW or CE2\ is HIGH.

85 ADSC\ Input Synchronous Address Status Controller: This active LOW input interrupts any ongoing

burst, causing a new external address to be registered. A READ or WRITE is performed

using the new address if CE\ is LOW. ADSC\ is also used to place the chip into power-

down state when CE\ is HIGH.

31 MODE Input Mode: This input selects the burst sequence. A LOW on this pin selects LINEAR BURST. A

NC or HIGH on this pin selects INTERLEAVED BURST. Do not alter input state while

device is operating.

64 ZZ Input Snooze Enable: This active HIGH, asynchronous input causes the device to enter a low-

power standby mode in which all data in the memory array is retained. When ZZ is active,

all other inputs are ignored.

(a) 58, 59, 62, 63, 68,

69, 72, 73

(b) 8, 9, 12,13, 18, 19,

22

,

23

DQa

DQb Input/

Output SRAM Data I/Os: Byte "a" is DQa pins; Byte "b" is DQb pins. Input data must meet setup

and hold times around the rising edge of CLK.

74, 24 NC/DQPa

NC/DQPb NC/ I/O No Connect/Parity Data I/Os: Byte "a" is DQPa pins; Byte "b" is DQPb pins.

15, 41,65, 91 VDD Supply Power Supply: See DC Electrical Characteristics and Operating Conditions for range.

4, 11, 20, 27, 54, 61,

70, 77 VDDQ Supply Isolated Output Buffer Supply: See DC Electrical Characterics and Operating Conditions for

range.

5, 10, 14, 17, 21, 26,

40, 55, 60, 67 71, 76,

90

VSS Supply Ground: GND

38, 39 DNU --- Do Not Use: These signals may either be unconnected or wired to GND to improve

package heat dissipation.

1-3, 6, 7, 16,25, 28-30,

51-53, 56,57, 66, 75,

78, 79, 95, 96

NC ----- No Connect: These signals are not internally connected and may be connected to ground to

improve package heat dissipation.

42, 43 NF No Function: These pins are internally connected to the die and will have the capacitance of

input pins. It is allowable to leave these pins unconnected or driven by signals.

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

3

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

INTERLEAVED BURST ADDRESS TABLE (MODE=NC OR HIGH)

LINEAR BURST ADDRESS TABLE (MODE=LOW)

FUNCTIONAL BLOCK DIAGRAM

NOTE: The Functional Block Diagram illustrates simplified device operation. See Truth Table, pin descriptions and timing

diagrams for detailed information.

18 18 16 18

SA0, SA1, SA

MODE

ADV\

CLK

ADSC\

ADSP\

BWb\

BWa\

BWE\

GW\

CE\

CE2

CE2\

OE\ 2

ADDRESS

REGISTER

BINARY

COUNTER AND

LOGIC

BYTE "b"

WRITE REGISTER

BYTE "a"

WRITE REGISTER

ENABLE

REGISTER

CLR

Q1

Q0

SA1'

SA0'

INPUT

REGISTERS

OUTPUT

BUFFERS

SENSE

AMPS

256K x 9 x 2

MEMORY

ARRAY

9

BYTE "b"

WRITE DRIVER

BYTE "a"

WRITE DRIVER

9

18 18 18

18

DQs

DQPa

DQPb

2SA0-SA1

FIRST ADDRESS (EXTERNAL) SECOND ADDRESS (INTERNAL) THIRD ADDRESS (INTERNAL) FOURTH ADDRESS (INTERNAL)

X…X00 X…X01 X…X10 X…X11

X…X01 X…X00 X…X11 X…X10

X…X10 X…X11 X…X00 X…X01

X…X11 X…X10 X…X01 X…X00

FIRST ADDRESS (EXTERNAL) SECOND ADDRESS (INTERNAL) THIRD ADDRESS (INTERNAL) FOURTH ADDRESS (INTERNAL)

X…X00 X…X01 X…X10 X…X11

X…X01 X…X10 X…X11 X…X00

X…X10 X…X11 X…X00 X…X01

X…X11 X…X00 X…X01 X…X10

PARTIAL TRUTH TABLE FOR WRITE COMMANDS

FUNCTION GW\ BWE\ BWa\ BWb\

READ H H X X

READ H L H H

WRITE Byte "a" H L L H

WRITE Byte "b" H L H L

WRITE All Bytes H L L L

WRITE All Bytes L X X X

NOTE: Using BWE\ and BWa\ through BWb\, any one or more bytes may be

written.

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

4

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

TRUTH TABLE

NOTES: 1. X means “Don’ t Care.” \ means active LOW . H means logic HIGH. L means logic LOW .

2. For WRITE\, L means any one or more byte write enable signals (BW a\, BWb\) and BWE\ are LOW or GW\ is LOW . WRITE\ = H for all BWx\,

BWE\, GW\ HIGH.

3. BWa\ enables WRITEs to DQas and DQPa. BWb\ enables WRITEs to DQbs and DQPb.

4. All inputs except OE\ and ZZ must meet setup and hold times around the rising edge (LOW to HIGH) of CLK.

5. Wait states are inserted by suspending burst.

6. For a WRITE operation following a READ operation, OE\ must be HIGH before the input data setup time and held HIGH throughout the input

data hold time.

7. This device contains circuitry that will ensure the outputs will be in High-Z during power-up.

8. ADSP\ LOW always initiates an internal READ at the L-H edge of CLK. A WRITE is performed by setting one or more byte write enable signals

and BWE\ LOW or GW\ LOW for the subsequent L-H edge of CLK. Refer to WRITE timing diagram for clarification.

OPERATION ADDRESS

USED CE\ CE2\ CE2 ZZ ADSP\ ADSC\ ADV\ WRITE\ OE\ CLK DQ

DESELECT Cycle, Power-Down NONE H X X L X L X X X L-H High-Z

DESELECT Cycle, Power-Down NONE L X L L L X X X X L-H High-Z

DESELECT Cycle, Power-Down NONE L H X L L X X X X L-H High-Z

DESELECT Cycle, Power-Down NONE L X L L H L X X X L-H High-Z

DESELECT Cycle, Power-Down NONE L H X L H L X X X L-H High-Z

SNOOZE MODE, Power-Down NONE X X X H X X X X X X High-Z

READ Cycle, Begin Burst EXTERNAL L L H L L X X X L L-H Q

READ Cycle, Begin Burst EXTERNAL L L H L L X X X H L-H High-Z

WRITE Cycle, Begin Burst EXTERNAL L L H L H L X L X L-H D

READ Cycle, Begin Burst EXTERNAL L L H L H L X H L L-H Q

READ Cycle, Begin Burst EXTERNAL L L H L H L X H H L-H High-Z

READ Cycle, Continue Burst NEXT X X X L H H L H L L-H Q

READ Cycle, Continue Burst NEXT X X X L H H L H H L-H High-Z

READ Cycle, Continue Burst NEXT H X X L X H L H L L-H Q

READ Cycle, Continue Burst NEXT H X X L X H L H H L-H High-Z

WRITE Cycle, Continue Burst NEXT X X X L H H L L X L-H D

WRITE Cycle, Continue Burst NEXT H X X L X H L L X L-H D

READ Cycle, Suspend Burst CURRENT X X X L H H H H L L-H Q

READ Cycle, Suspend Burst CURRENT X X X L H H H H H L-H High-Z

READ Cycle, Suspend Burst CURRENT H X X L X H H H L L-H Q

READ Cycle, Suspend Burst CURRENT H X X L X H H H H L-H High-Z

WRITE Cycle, Suspend Burst CURRENT X X X L H H H L X L-H D

WRITE Cycle, Suspend Burst CURRENT H X X L X H H L X L-H D

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

5

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

ABSOLUTE MAXIMUM RATINGS*

Voltage on VDD Supply Relative to VSS............-0.5V to +4.6V

Voltage on VDDQ Supply Relative to VSS.........-0.5V to +4.6V

Storage Temperature (plastic) .....................-55°C to +125°C

Max Junction Temperature**.......................................+150°C

Short Circuit Output Current..........…...........................100mA

*Stresses 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 ex-

tended periods may affect reliability .

**Maximum junction temperature depends upon package type, cycle

time, loading, ambient temperature and airflow .

DC ELECTRICAL CHARACTERISTICS AND RECOMMENDED OPERATING CONDITIONS

(-55oC < TA < +125oC and -40oC<TA<+85oC; VDD = +3.3V +0.3V/-0.165V unless otherwise noted)

DESCRIPTION CONDITIONS SYMBOL MIN MAX UNITS NOTES

Input High (Logic 1) Voltage V

IH

2.0 V

DD

+0.3 V 1, 2

Input Low (Logic 0) Voltage V

IL

-0.3 0.8 V 1, 2

Input Leakage Current (0V<V

IN

<V

DD

) IL

I

-2 2 µΑ 3

Output Leakage Current Output(s) disabled;

0V<V

IN

<V

DD

IL

O

-2 2 µΑ

Output High Voltage I

OH

= -4.0mA V

OH

2.4 -- V 1, 4

Output Low Voltage I

OL

= 8.0 mA V

OL

-- 0.5 V 1, 4

Supply Voltage V

DD

3.135 3.6 V 1

Isolated Output Buffer Supply V

DD

Q3.135 3.6 V 1, 5

NOTES:1. All voltages referenced to VSS (GND)

2. Overshoot: VIH < +4.6V for t < tKC/2 for I < 20mA

Undershoot: VIL > -0.7V for t < tKC/2 for I < 20mA

Power-up: VIH < +3.6V and VDD<3.135V for t < 200ms

3. MODE pin has an internal pull-up, and input leakage = ±10µA.

4. The load used for VOH, VOL testing is shown in Figure 2 for 3.3V I/O. AC load current is higher then the stated DC values.

5. VDDQ should never exceed VDD. VDD and VDDQ can be connected together, for 3.3V I/O operation only.

6. This parameter is sampled.

CAPACITANCE

DESCRIPTION CONDITIONS SYM MAX UNITS NOTES

Control Input Capacitance C

I

4pF6

Input/Output Capacitance (DQ) C

O

5pF6

Address Capacitance C

A

3.5 pF 6

Clock Capacitance C

CK

3.5 pF 6

T

A

= 25°C; f = 1MHz;

V

DD

= 3.3V

THERMAL RESIST ANCE

DESCRIPTION CONDITIONS SYM TYP UNITS NOTES

Thermal Resistance

(Junction to Ambient) θ

JA

46 °C/W 6

Thermal Resistance

(Junction to Top of Case) θ

JC

2.8 °C/W 6

Test conditions follow standard test

methods and procedures for measuring

thermal impedance, per EIA/JESD51

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

6

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

IDD ELECTRICAL CHARACTERISTICS AND RECOMMENDED OPERATING CONDITIONS

(-55oC < TA < +125oC and -40oC<TA<+85oC; VDD = +3.3V +0.3V/-0.165V unless otherwise noted)

CONDITIONS SYM -8 -9 -10 UNITS NOTES

Device selected; all inputs < VIL or > VIH;

Cycle time > tKC (MIN); VDD = MAX; Outputs Open IDD 375 325 250 mA 2, 3, 4

Power Supply Current:

Idle

Device selected; VDD = MAX; ADSC\, ADSP\,

ADV\, GW\, BWx\ > VIH; All inputs < VSS +0.2 or

> VDDQ -0.2; Cycle time > tKC (MIN);

Outputs Open

IDD1 100 85 65 mA 2, 3, 4

CMOS Standby Device deselected; VDD = MAX;

All inputs < Vss +0.2 or > VDDQ -0.2;

All inputs static; CLK frequency =0 ISB2 10 10 10 mA 3, 4

TTL Standby Device deselected; VDD = MAX;

All inputs < VIL or > VIH;

All inputs static; CLK frequency = 0 ISB3 25 25 25 mA 3, 4

Clock Running

Device deselected; VDD = MAX;

ASDP\, ADV\, GW\, BWx\ > VIH;

All inputs < VSS +0.2 or > VDDQ -0.2;

Cycle time > tKC (MIN)

ISB4 100 85 65 mA 3, 4

Power Supply Current:

Operating

PARAMETER MAX

NOTES:1. V DDQ = +3.3V +0.3V/-0.165V for 3.3V I/O configuration.

2. IDD is specified with no output current and increases with faster cycle times. IDDQ increases with faster cycle

times and greater output loading.

3. “Device deselected” means device is in power-down mode as defined in the truth table. “Device selected” means

device is active (not in power-down mode).

4. Typical values are measured at 3.3V, 25°C and 15ns cycle time.

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

7

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

ELECTRICAL CHARACTERISTICS AND RECOMMENDED AC OPERATING CONDITIONS

(Note 1) -55oC < TA < +125oC and -40oC<TA<+85oC; VDD = +3.3V +0.3V/-0.165V unless otherwise noted)

MIN MAX MIN MAX MIN MAX

Clock cycle time

t

KC

8.8 10 15 ns

Clock frequency

t

KF

113 100 66 MHz

Clock HIGH time

t

KH

2.5 3.0 4.0 ns 2

Clock LOW time

t

KL

2.5 3.0 4.0 ns 2

Clock to output valid

t

KQ

7.5 8.5 10 ns

Clock to output invalid t

KQX

1.5 3.0 3.0

ns

3

Clock to output in Low-Z t

KQLZ

1.5 3.0 3.0

ns

3, 4, 5

Clock to output in High-Z t

KQHZ

4.2 5.0 5.0

ns

3, 4, 5

OE\ to output valid t

OEQ

4.2 5.0 5.0

ns

6

OE\ to output in Low-Z t

OELZ

000

ns

3, 4, 5

OE\ to output in High-Z t

OEHZ

4.2 5.0 5.0

ns

3, 4, 5

Address t

AS

1.5 1.8 2.0

ns

7, 8

Address status (ADSC\, ADSP\) t

ADSS

1.5 1.8 2.0

ns

7, 8

Address advance (ADV\) t

AAS

1.5 1.8 2.0

ns

7, 8

Byte write enables (BWa\-BWb\, GW\, BWE\) t

WS

1.5 1.8 2.0

ns

7, 8

Data-in t

DS

1.5 1.8 2.0

ns

7, 8

Chip enable (CE\) t

CES

1.5 1.8 2.0

ns

7, 8

Address t

AH

0.5 0.5 0.5

ns

7, 8

Address status (ADSC\, ADSP\) t

ADSH

0.5 0.5 0.5

ns

7, 8

Address advance (ADV\) t

AAH

0.5 0.5 0.5

ns

7, 8

Byte write enables (BWa\-BWb\, GW\, BWE\) t

WH

0.5 0.5 0.5

ns

7, 8

Data-in t

DH

0.5 0.5 0.5

ns

7, 8

Chip enable (CE\) t

CEH

0.5 0.5 0.5

ns

7, 8

OUTPUT TIMES

SETUP TIMES

HOLD TIMES

NOTESUNITSSYMBOL

CLOCK

DESCRIPTION -9-8 -10

NOTES:

1. T est conditions as specified with the output loading shown in Figure 1 for 3.3V I/O (VDDQ = +3.3V +0.3V/-0.165V) unless othe rwise

noted.

2. Measured as HIGH above VIH and LOW below VIL.

3. This parameter is measured with the output loading shown in Figure 2 for 3.3V I/O.

4. This parameter is sampled.

5. T ransition is measured ±500mV from steady state voltage.

6. OE\ is a “Don’t Care” when a byte write enable is sampled LOW.

7. A READ cycle is defined by byte write enables all HIGH or ADSP\ LOW for the required setup and hold times. A WRITE cycle is

defined by at least one byte write enable LOW and ADSP\ HIGH for the required setup and hold times.

8. This is a synchronous device. All addresses must meet the specified setup and hold times for all rising edges of CLK when either ADSP\ or

ADSC\ is LOW and chip enabled. All other synchronous inputs must meet the setup and hold times with stable logic levels for all rising edges

of clock (CLK) when the chip is enabled. Chip enable must be valid at each rising edge of CLK when either ADSP\ or ADSC\ is LOW to

remain enabled.

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

8

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

A C TEST CONDITIONS OUTPUT LO ADS

V

IH

= (V

DD

/2.2) + 1.5V

V

IL

= (V

DD

/2.2) - 1.5V

Input rise and fall times 1ns

Input timing reference levels V

DD

/2.2

Output reference levels V

DD

Q/2.2

Output load See Figures 1 and 2

Input pulse levels

3.3v

DQ

Fig. 2 OUTPUT LOAD EQUIVALENT

351Ω5 pF

317Ω

Fig. 1 OUTPUT LOAD EQUIVALENT

DQ

50Ω

Z0=50Ω

Vt = 1.5V

LOAD DERATING CURVES

ASI’ s 256K x 18 Synchronous Burst SRAM timing is dependent upon

the capacitive loading on the outputs.

SNOOZE MODE

SNOOZE MODE is a low-current, “power-down” mode in which the

device is deselected and current is reduced to ISB2Z. The duration of

SNOOZE MODE is dictated by the length of time ZZ is in a HIGH

state. After the device enters SNOOZE MODE, all inputs except ZZ

become gated inputs and are ignored.

ZZ is an asynchronous, active HIGH input that causes the device to

enter SNOOZE MODE. When ZZ becomes a logic HIGH, ISB2Z is

guaranteed after the setup time tZZ is met. Any READ or WRITE

operation pending when the device enters SNOOZE MODE is not

quaranteed to complete successfully. Therefore, SNOOZE MODE

must not be initiated until valid pending operations are completed.

* Except ZZ

1

23

4

1

23

4

1

23

4

1234

Don’t Care

SNOOZE MODE W A VEFORM

DESCRIPTION CONDITIONS SYM MIN MAX UNITS NOTES

Current during SNOOZE MODE ZZ > V

IH

I

SB2Z

10 mA

ZZ active to input ignored t

ZZ

t

KC

ns 1

ZZ inactive to input sampled t

RZZ

t

KC

ns 1

ZZ active to snooze current t

ZZI

t

KC

ns 1

ZZ inactive to exit snooze current t

RZZI

0ns1

SNOOZE MODE ELECTRICAL CHARACTERISTICS

NOTE: 1. This parameter is sampled.

12345

1234567890

1

23456789

0

1

23456789

0

1234567890

1

12

tZZ tRZZ

tZZI

ISB2 tRZZI

CLK

ZZ

ISUPPLY

ALL INPUTS*

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

9

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

READ TIMING

NOTE: 1. Q(A2) referes to output from address A2. Q(A2+1) refers to output from the next internal burst address following A2.

2. CE2\ and CE2 have timing identical to CE\. On this diagram, when CE\ is LOW, CE2\ is LOW and CE2 is HIGH. When CE\ is HIG H, CE2\ is HIGH and CE2 is LOW.

3. Timing is shown assuming that the device was not enabled before entering into this sequence.

4. Outputs are disabled tKQHZ after deselect.

READ TIMING PARAMETERS

MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX

t

KC

8.8 10 15 ns t

AS

1.5 1.8 2.0 ns

t

KF

113 100 66 MHz t

ADSS

1.5 1.8 2.0 ns

t

KH

2.5 3.0 4.0 ns t

AAS

1.5 1.8 2.0 ns

t

KL

2.5 3.0 4.0 ns t

WS

1.5 1.8 2.0 ns

t

KQ

7.5 8.5 10 ns t

CES

1.5 1.8 2.0 ns

t

KQX

1.5 3.0 3.0 ns t

AH

0.5 0.5 0.5 ns

t

KQLZ

1.5 3.0 3.0 ns t

ADSH

0.5 0.5 0.5 ns

t

KQHZ

4.2 5.0 5.0 ns t

AAH

0.5 0.5 0.5 ns

t

OEQ

4.2 5.0 5.0 ns t

WH

0.5 0.5 0.5 ns

t

OELZ

000 ns

t

CEH

0.5 0.5 0.5 ns

t

OEHZ

4.2 5.0 5.0 ns

-10-9-8

SYM -10 UNITSUNITS SYM -8 -9

1234567890123

1234

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

1234

12345

123456

1234567890123456

12345

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

12345

1234567

1

23456

7

1

23456

7

1

23456

7

1

23456

7

1

23456

7

1234567

1

CLK

ADSP\

ADSC\

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

ADDRESS A2

BWE\, GW\,

BWa\-BWb\

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

CE\

(Note 2)

ADV\

OE\

SINGLE READ BURST READ

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

Q

12345

A1

12345678

123

1

2

3

1

2

3

1

2

3

1

2

3

123

12345678

12345678901234567890123456789012123456789012345678901234567890121234567890123456789

1

234567890123456789012345678901212345678901234567890123456789012123456789012345678

9

1

234567890123456789012345678901212345678901234567890123456789012123456789012345678

9

1

234567890123456789012345678901212345678901234567890123456789012123456789012345678

9

1

234567890123456789012345678901212345678901234567890123456789012123456789012345678

9

12345678901234567890123456789012123456789012345678901234567890121234567890123456789

12

Q(A2) Q(A2+2)

12

Q(A2+3)

12

Q(A2)

123

Q(A2+1)

12

Q(A2+2)

123456

1234567

123456

12345

123456

12345

123456

12345678

1

234567

8

1

234567

8

1

234567

8

1

234567

8

12345678

12

123456

12345

123456

Q(A1) Q(A2+1)

123456

1234567

123456

1234567890123456789012

1

23456789012345678901

2

1

23456789012345678901

2

1

23456789012345678901

2

1

23456789012345678901

2

1234567890123456789012

12

123456

123456789012345678901234567890121234567890123456789012345678901212345678901234567

123456

1234567890123456789012

1

23456789012345678901

2

1

23456789012345678901

2

1

23456789012345678901

2

1

23456789012345678901

2

1

23456789012345678901

2

1234567890123456789012

12

123456789012

123456

1

2345

6

1

2345

6

1

2345

6

1

2345

6

1

2345

6

123456

1

123

1234

tADSS

tADSH

123456

tAS

tAH

tKC

tKL

tKH

tADSS

tADSH

tWS tWH

tCES tCEH

123456

tAAS tAAH

ADV\ suspends burst.

High-Z

tOEHZ

tKQLZ

tKQ

tOEQ tOELZ tKQ

tKQX

tKQHZ

Burst wraps around

to its initial state.

(NOTE 1)

Deselect Cycle

(Note 4)

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

10

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

NOTE: 1. D(A2) refers to output from address A2. D(A2+1) refres to output from the next internal burst address following A2.

2. CE2\ and CE2 have timing identical to CE\. On this diagram, when CE\ is LOW, CE2\ is LOW and CE2 is HIGH. When CE\ is HIGH, CE2\ is HIGH and CE2 is LOW.

3. OE\ must be HIGH before the input data setup and held HIGH throughout the data hold time. This prevents input/output data contention for the time period

prior to the byte write enable inputs being sampled.

4. ADV\ must be HIGH to permit a WRITE to the loaded address.

5. Full-width WRITE can be initiated by GW\ LOW; or GW\ HIGH and BWE\, BWa\ and BWb\ LOW.

WRITE TIMING

MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX

t

KC

8.8 10 15 ns t

DS

1.5 1.8 2.0 ns

t

KF

113 100 66 MHz t

CES

1.5 1.8 2.0 ns

t

KH

2.5 3.0 4.0 ns t

AH

0.5 0.5 0.5 ns

t

KL

2.5 3.0 4.0 ns t

ADSH

0.5 0.5 0.5 ns

t

OEHZ

4.2 5.0 5.0 ns t

AAH

0.5 0.5 0.5 ns

t

AS

1.5 1.8 2.0 ns t

WH

0.5 0.5 0.5 ns

t

ADSS

1.5 1.8 2.0 ns t

DH

0.5 0.5 0.5 ns

t

AAS

1.5 1.8 2.0 ns t

CEH

0.5 0.5 0.5 ns

t

WS

1.5 1.8 2.0 ns

-10-9-8

SYM -10 UNITSUNITS SYM -8 -9

WRITE TIMING P ARAMETERS

1234

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

1234

12345

123456

1234

1234567890

1

23456789

0

1

23456789

0

1

23456789

0

1

23456789

0

1234567890

12345

1234

1234567890

1

23456789

0

1

23456789

0

1

23456789

0

1

23456789

0

1

23456789

0

1234567890

12345

1234

123456789012

123456

1

2345

6

1

2345

6

1

2345

6

1

2345

6

1

2345

6

123456

12

12345

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

12345

1234

1234567890

1

23456789

0

1

23456789

0

1

23456789

0

1

23456789

0

1234567890

12345

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

12345

1234

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

12345

1234

1234567890

1

23456789

0

1

23456789

0

1

23456789

0

1

23456789

0

1

23456789

0

1234567890

12345

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

12345

CLK

ADSP\

ADSC\

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

○○○ ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

○○○ ○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

ADDRESS A2

BEW\,

BWa\ - BWb\

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

CE\

(NOTE 2)

ADV\

OE\

SINGLE WRITE BURST WRITE

GW\

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

D

Extended

BURST WRITE

1234

A1

12345678

123

1

2

3

1

2

3

1

2

3

1

2

3

123

12345678

1234567890123456789012345678901212345678901234

1

23456789012345678901234567890121234567890123

4

1

23456789012345678901234567890121234567890123

4

1

23456789012345678901234567890121234567890123

4

1

23456789012345678901234567890121234567890123

4

1

23456789012345678901234567890121234567890123

4

12

1

A3

12345678

123456789012345678901

1

2345678901234567890

1

2345678901234567890

1

2345678901234567890

1

2345678901234567890

1

2345678901234567890

1

12

123456789012345678

1234567890123456789012345678901212345678901234567890123456789012123456789012

1

23456789012345678901234567890121234567890123456789012345678901212345678901

2

1

23456789012345678901234567890121234567890123456789012345678901212345678901

2

1

23456789012345678901234567890121234567890123456789012345678901212345678901

2

1

23456789012345678901234567890121234567890123456789012345678901212345678901

2

1234567890123456789012345678901212345678901234567890123456789012123456789012

D(A2) D(A2+2)

12

D(A2+3)

12

D(A3)

12

D(A3+1)

12

D(A3+2)

123456

1234

123456

1234567

123456

12345678

1234567

1

23456

7

1

23456

7

1

23456

7

1

23456

7

1

23456

7

12

1234

123456

1234

1234567890123456789012345678901212345678901234567890

1

23456789012345678901234567890121234567890123456789

0

1

23456789012345678901234567890121234567890123456789

0

1

23456789012345678901234567890121234567890123456789

0

1

23456789012345678901234567890121234567890123456789

0

1

23456789012345678901234567890121234567890123456789

0

1234567890123456789012345678901212345678901234567890

12345

1234567

1234567890123456789012345

1

23456789012345678901234

5

1

23456789012345678901234

5

1

23456789012345678901234

5

1

23456789012345678901234

5

1

23456789012345678901234

5

1234567890123456789012345

12

12345

123456

D(A1) D(A2+1)

tADSS

tADSH

tKC

tKL

tKH

tAS

tAH

123456

tADSS

tADSH

123456

ADSC\ extends burst.

BYTE WRITE signals are ignored

when ADSP\ is LOW. tWS tWH

tWS tWH

(Note 5)

123456

123456789

1234567

123456789

12345

1

234

5

1

234

5

1

234

5

1

234

5

12345

tCES tCEH

tAAS tAAH

(Note 4) ADV\ suspends burst.

(Note 3)

Q

1234

12345

123456

12345

6

123456

12

tOEHZ

123

12

D(A2+1)

123

12

(Note 1)

High-Z

BURST READ

12345

1

234

5

1

234

5

12345

Don’t Care

tDS tDH

12345678901234567

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

11

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

NOTE: 1. Q(A4) refers to output from address A4. Q(A4+1) refers to output from the next internal burst address following A4.

2. CE2\ and CE2 have timing identical to CE\. On this diagram, when CE\ is LOW, CE2\ is LOW and CE2 is HIGH. When CE\ is HIGH, CE2\ is HIGH and CE2 is LOW.

3. The data bus (Q) remains in High-Z following a WRITE cycle unless an ADSP\, ADSC\, or ADV\ cycle is performed.

4. GW\ is HIGH.

5. Back-to-back READs may be controlled by either ADSP\ or ADSC\.

6. Timing is shown assuming that the device was not enabled before entering into this sequence.

READ/WRITE TIMING6

MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX MIN MAX

t

KC

8.8 10 15 ns t

WS

1.5 1.8 2.0 ns

t

KF

113 100 66 MHz t

DS

1.5 1.8 2.0 ns

t

KH

2.5 3.0 4.0 ns t

CES

1.5 1.8 2.0 ns

t

KL

2.5 3.0 4.0 ns t

AH

0.5 0.5 0.5 ns

t

KQ

7.5 8.5 10 ns t

ADSH

0.5 0.5 0.5 ns

t

OELZ

000 ns

t

WH

0.5 0.5 0.5 ns

t

OEHZ

3.5 4.2 5.0 ns t

DH

0.5 0.5 0.5 ns

t

AS

1.5 1.8 2.0 ns t

CEH

0.5 0.5 0.5 ns

t

ADSS

1.5 1.8 2.0 ns

-10-9-8

SYM -10 UNITSUNITS SYM -8 -9

READ/WRITE PARAMETERS

123456789012345678

12345

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

12345

CLK

ADSP\

ADSC\

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

ADDRESS A2

BWE\, GW\

BWa\ - BWb\

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

CE\

(Note 2)

ADV\

OE\

Back-to-Back READS

(NOTE 5)

BURST READ

○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

D

Back-to-Back

WRITEs

12345

12345678

123

1

2

3

1

2

3

1

2

3

1

2

3

123

12345678

12345678901234567890123456789012123

1

234567890123456789012345678901212

3

1

234567890123456789012345678901212

3

1

234567890123456789012345678901212

3

1

234567890123456789012345678901212

3

12345678901234567890123456789012123

12

1

A5

D(A5) D(A6)

123456

123456789012345

1234567890123456789012345678901212345678

123456789012345678901234567890121234567

8

123456789012345678901234567890121234567

8

123456789012345678901234567890121234567

8

123456789012345678901234567890121234567

8

123456789012345678901234567890121234567

8

1234567890123456789012345678901212345678

1234

12345

D(A3)

12345

A1 A3

12345678

123

1

2

3

1

2

3

1

2

3

1

2

3

123

A4

1234567890123

123456

12345678901234567890123456789012123456789012

1

234567890123456789012345678901212345678901

2

1

234567890123456789012345678901212345678901

2

1

234567890123456789012345678901212345678901

2

1

234567890123456789012345678901212345678901

2

12345678901234567890123456789012123456789012

12

SINGLE WRITE

tKC

tKL

tKH

tADSS

tADSH

123456

12345

123456

123

A6

123

tAS

12345

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

12345

tAH

123456

12345

1234

123456789

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

1

2345678

9

123456789

1234

12345

123456

tCES

tCEH

tWS

tWH

12345678901234567

123456

1234

Q(A1)

123

Q(A2) Q(A4) Q(A4+1)

12

Q(A4+2)

12

Q(A4+3)

1

12

Q

High-Z

tDS tDH tOELZ

tKQ (NOTE 1)

123456

1

2345

6

1

2345

6

1

2345

6

123456

Don’t Care

12345

1

234

5

1

234

5

1

234

5

12345

Undefined

tOEHZ

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

12

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

MECHANICAL DEFINITIONS

ASI Case #1001 (Package Designator DQ)

16.00 +0.20/-0.05

14.00 + 0.10

22.10 + 0.10/-0.15

20.10 + 0.10

0.62

Pin #1 ID

NOTE: 1. All dimensions in Millimeters (MAX/MIN) or typical where noted.

2. Package width and length do not include mold protrusion; allowable mold protursion is 0.25mm per side.

1.00 TYP

DET AIL A

0.10 +0.10/-0.05 Gage Plane

0.25

0.60 + 0.15

0.32 +0.06/-0.10

0.65

1.50 + 0.10

1.40 + 0.05

0.10

See Detail A

0.15 +0.03/-0.02

AS5SS256K18

Rev. 2.0 12/00

Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.

13

SSRAM

AS5SS256K18

Austin Semiconductor, Inc.

EXAMPLE: AS5SS256K18DQ-8/IT

Device Number Package

Type Speed ns Process

AS5SS256K18 DQ -8 IT only

AS5SS256K18 DQ -9 /*

AS5SS256K18 DQ -10 /*

ORDERING INFORMA TION

*AVAILABLE PROCESSES

IT = Industrial Temperature Range -40oC to +85oC

XT = Extended T emperature Range -55oC to +125oC