AS7C251MPFS32A-200TQC - Alliance Semiconductor

February 2005

AS7C251MPFS32A

AS7C251MPFS36A

2/14/05, v.1.3 Alliance Semiconductor 1 of 19

2.5V 1M × 32/36 pipelined burst synchronous SRAM

Features

• Organization: 1,048,576 words × 32 or 36 bits

• Fast clock speeds to 200 MHz

• Fast clock to data access: 3.1/3.5/3.8 ns

•Fast OE

access time: 3.1/3.5/3.8 ns

• Fully synchronous register-to-register operation

• Single-cycle deselect

• Asynchronous output enable control

• Available in 100-pin TQFP package

• Individual byte write and global write

• Multiple chip enables for easy expansion

• 2.5V core power supply

• Linear or interleaved burst control

• Snooze mode for reduced power-standby

• Common data inputs and data outputs

Logic block diagram

Selection guide

-200 -166 -133 Units

Minimum cycle time 5 6 7.5 ns

Maximum clock frequency 200 166 133 MHz

Maximum clock access time 3.1 3.5 3.8 ns

Maximum operating current 450 400 350 mA

Maximum standby current 170 150 140 mA

Maximum CMOS standby current (DC) 90 90 90 mA

[19:0]

20 18 20

Q1 1M × 32/36

Memory

array

Burst logic

CLK

CLR

Address

CLK

Byte write

registers

CLK

Byte write

registers

CLK

Byte write

registers

CLK

Byte write

registers

Enable

CLK

Enable

CLK

delay

Output

registers Input

registers

Power

down

DQ[a:d]

32/36

GWE

BWE

ADV

ADSC

ADSP

CLK

CE0

CE1

CE2

LBO

CLK CLK

32/36

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AS7C251MPFS32A

AS7C251MPFS36A

2.5V 32 Mb Synchronous SRAM products list1,2

1 Core Power Supply: VDD = 2.5V + 0.125V

2 I/O Supply Voltage: VDDQ = 2.5V + 0.125V

PL-SCD : Pipelined Burst Synchronous SRAM - Single Cycle Deselect

PL-DCD : Pipelined Burst Synchronous SRAM - Double Cycle Deselect

FT : Flow-through Burst Synchronous SRAM

NTD1-PL : Pipelined Burst Synchronous SRAM with NTDTM

NTD-FT : Flow-through Burst Synchronous SRAM with NTDTM

Org Part Number Mode Speed

2MX18 AS7C252MPFS18A PL-SCD 200/166/133 MHz

1MX32

AS7C251MPFS32A PL-SCD 200/166/133 MHz

1MX36 AS7C251MPFS36A PL-SCD 200/166/133 MHz

2MX18

AS7C252MPFD18A PL-DCD 200/166/133 MHz

1MX32

AS7C251MPFD32A PL-DCD 200/166/133 MHz

1MX36 AS7C251MPFD36A PL-DCD 200/166/133 MHz

2MX18 AS7C252MFT18A FT 7.5/8.5/10 ns

1MX32 AS7C251MFT32A FT 7.5/8.5/10 ns

1MX36

AS7C251MFT36A FT 7.5/8.5/10 ns

2MX18

AS7C252MNTD18A NTD-PL 200/166/133 MHz

1MX32

AS7C251MNTD32A NTD-PL 200/166/133 MHz

1MX36

AS7C251MNTD36A NTD-PL 200/166/133 MHz

2MX18

AS7C252MNTF18A NTD-FT 7.5/8.5/10 ns

1MX32

AS7C251MNTF32A NTD-FT 7.5/8.5/10 ns

1MX36

AS7C251MNTF36A NTD-FT 7.5/8.5/10 ns

1NTD: No Turnaround Delay. NTDTM is a trademark of Alliance Semiconductor Corporation. All trademarks mentioned in this document are the property of

their respective owners.

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AS7C251MPFS32A

AS7C251MPFS36A

Pin assignment

100-pin TQFP - top view

LBO

100

CE0

CE1

BWd

BWc

BWb

BWa

CE2

CLK

GWE

BWE

ADSC

ADSP

ADV

TQFP 14 x 20mm

NC/DQPc

DQc0

DQc1

DDQ

SSQ

DQc2

DQc3

DQc4

DQc5

SSQ

DDQ

DQc6

DQc7

DQd0

DQd1

DDQ

SSQ

DQd2

DQd3

DQd4

DQd5

SSQ

DDQ

DQd6

DQd7

NC/DQPd

DQPb/NC

DQb7

DQb6

DDQ

SSQ

DQb5

DQb4

DQb3

DQb2

SSQ

DDQ

DQb1

DQb0

DQa7

DQa6

DDQ

SSQ

DQa5

DQa4

DQa3

DQa2

SSQ

DDQ

DQa1

DQa0

DQPa/NC

Note: For pins 1, 30, 51, and 80, NC applies to the x32 configuration. DQPn applies to the x36 configuration.

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AS7C251MPFS36A

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Functional description

The AS7C251MPFS32A/36A is a high-performance CMOS 32-Mbit synchronous Static Random Access Memory (SRAM)

device organized as 1,048,576 words x 32/36. It incorporates a two-stage register-register pipeline for highest frequency on any

given technology.

Fast cycle times of 5/6/7.5 ns with clock access times (tCD) of 3.1/3.5/3.8 ns enable 200, 166 and 133MHz bus frequencies.

Three chip enable (CE) inputs permit easy memory expansion. Burst operation is initiated in one of two ways: the controller

address strobe (ADSC), or the processor address strobe (ADSP). The burst advance pin (ADV) allows subsequent internally

generated burst addresses.

Read cycles are initiated with ADSP (regardless of WE and ADSC) using the new external address clocked into the on-chip

address register when ADSP is sampled low, the chip enables are sampled active, and the output buffer is enabled with OE. In

a read operation, the data accessed by the current address registered in the address registers by the positive edge of CLK are

carried to the data-out registers and driven on the output pins on the next positive edge of CLK. ADV is ignored on the clock

edge that samples ADSP asserted, but is sampled on all subsequent clock edges. Address is incremented internally for the next

access of the burst when ADV is sampled low and both address strobes are high. Burst mode is selectable with the

LBO

input.

With

LBO

unconnected or driven high, burst operations use an interleaved count sequence. With

LBO

driven low, the device

uses a linear count sequence.

Write cycles are performed by disabling the output buffers with OE and asserting a write command. A global write enable

GWE writes all 32/36 bits regardless of the state of individual BW[a:d] inputs. Alternately, when GWE is high, one or more

bytes may be written by asserting BWE and the appropriate individual byte BWn signals.

BWn is ignored on the clock edge that samples ADSP low, but it is sampled on all subsequent clock edges. Output buffers are

disabled when BWn is sampled LOW regardless of OE. Data is clocked into the data input register when BWn is sampled low.

Address is incremented internally to the next burst address if BWn and ADV are sampled low. This device operates in single-

cycle deselect feature during read cycles.

Read or write cycles may also be initiated with ADSC instead of ADSP. The differences between cycles initiated with ADSC

and ADSP are as follows:

ADSP must be sampled high when ADSC is sampled low to initiate a cycle with ADSC.

WE signals are sampled on the clock edge that samples ADSC low (and ADSP high).

Master chip enable CE0 blocks ADSP, but not ADSC.

The AS7C251MPFS32A/36A family operates from a core 2.5V power supply. These devices are available in a 100-pin TQFP

package.

TQFP capacitance

* Guaranteed not tested

TQFP thermal resistance

Parameter Symbol Test conditions Min Max Unit

Input capacitance CIN*VIN = 0V - 5 pF

I/O capacitance CI/O*VOUT = 0V - 7 pF

Description Conditions Symbol Typical Units

Thermal resistance

(junction to ambient)1

1 This parameter is sampled

Test conditions follow standard test methods

and procedures for measuring thermal

impedance, per EIA/JESD51

1–layer θJA 40 °C/W

4–layer θJA 22 °C/W

Thermal resistance

(junction to top of case)1θJC 8°C/W

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AS7C251MPFS32A

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Signal descriptions

Snooze Mode

SNOOZE MODE is a low current, power-down mode in which the device is deselected and current is reduced to ISB2. The duration of

SNOOZE MODE is dictated by the length of time the ZZ is in a High state.

The ZZ pin is an asynchronous, active high input that causes the device to enter SNOOZE MODE.

When the ZZ pin becomes a logic High, ISB2 is guaranteed after the time tZZI is met. After entering SNOOZE MODE, all inputs except ZZ is

disabled and all outputs go to High-Z. Any operation pending when entering SNOOZE MODE is not guaranteed to successfully complete.

Therefore, SNOOZE MODE (READ or WRITE) must not be initiated until valid pending operations are completed. Similarly, when exiting

SNOOZE MODE during tPUS, only a DESELECT or READ cycle should be given while the SRAM is transitioning out of SNOOZE MODE.

Pin I/O Properties Description

CLK I CLOCK Clock. All inputs except OE, ZZ, and LBO are synchronous to this clock.

A,A0,A1 I SYNC Address. Sampled when all chip enables are active and when ADSC or ADSP are asserted.

DQ[a,b,c,d] I/O SYNC Data. Driven as output when the chip is enabled and when OE is active.

CE0 ISYNC

Master chip enable. Sampled on clock edges when ADSP or ADSC is active. When CE0 is inactive,

ADSP is blocked. Refer to the “Synchronous truth table” for more information.

CE1, CE2 ISYNC

Synchronous chip enables, active high, and active low, respectively. Sampled on clock edges when

ADSC is active or when CE0 and ADSP are active.

ADSP I SYNC Address strobe processor. Asserted low to load a new address or to enter standby mode.

ADSC I SYNC Address strobe controller. Asserted low to load a new address or to enter standby mode.

ADV I SYNC Advance. Asserted low to continue burst read/write.

GWE ISYNC

Global write enable. Asserted low to write all 32/36 bits. When high, BWE and BW[a:d] control write

enable.

BWE I SYNC Byte write enable. Asserted low with GWE high to enable effect of BW[a:d] inputs.

BW[a,b,c,d] ISYNC

Write enables. Used to control write of individual bytes when GWE is high and BWE is low. If any of

BW[a:d] is active with GWE high and BWE low, the cycle is a write cycle. If all BW[a:d] are inactive,

the cycle is a read cycle.

OE I ASYNC Asynchronous output enable. I/O pins are driven when OE is active and chip is in read mode.

LBO ISTATIC

Selects Burst mode. When tied to VDD or left floating, device follows interleaved Burst order. When

driven Low, device follows linear Burst order. This signal is internally pulled High.

ZZ I ASYNC Snooze. Places device in low power mode; data is retained. Connect to GND if unused.

NC - - No connect

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Write enable truth table (per byte)

Key: X = don’t care, L = low, H = high, n = a, b, c, d;

BWE

BWn

= internal write signal.

Asynchronous Truth Table

Notes:

1. X means “Don’t Care”

2. ZZ pin is pulled down internally

3. For write cycles that follows read cycles, the output buffers must be disabled with OE, otherwise data bus contention will occur.

4. Snooze mode means power down state of which stand-by current does not depend on cycle times

5. Deselected means power down state of which stand-by current depends on cycle times

Burst sequence table

Function GWE BWE BWa BWb BWc BWd

Write All Bytes LXXXXX

HLLLLL

Write Byte a H L L H H H

Write Byte c and d H L H H L L

Read HHXXXX

HLHHHH

Operation ZZ OE I/O Status

Snooze mode H X High-Z

Read L L Dout

L H High-Z

Write L X Din, High-Z

Deselected L X High-Z

Interleaved burst address (LBO = 1) Linear burst address (LBO = 0)

A1 A0 A1 A0 A1 A0 A1 A0 A1 A0 A1 A0 A1 A0 A1 A0

Starting Address 0 0 0 1 1 0 1 1 Starting Address 0 0 0 1 1 0 1 1

First Increment 0 1 0 0 1 1 1 0 First Increment 0 1 1 0 1 1 0 0

Second Increment 1 0 1 1 0 0 0 1 Second Increment 1 0 1 1 0 0 0 1

Third Increment 1 1 1 0 0 1 0 0 Third Increment 1 1 1 0 0 1 1 0

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Synchronous truth table [4]

CE01

1 X = don’t care, L = low, H = high

CE1 CE2 ADSP ADSC ADV

WRITE

[2]

2 For WRITE, L means any one or more byte write enable signals (BWa, BWb, BWc or BWd) and BWE are LOW or GWE is LOW. WRITE = HIGH for all

BWx, BWE, GWE HIGH. See "Write enable truth table (per byte)," on page 6 for more information.

OE Address accessed CLK Operation DQ

HXXXLX X X NA L to H DeselectHi−Z

L L X L X X X X NA L to H Deselect Hi−Z

L L X H L X X X NA L to H Deselect Hi−Z

L X H L X X X X NA L to H Deselect Hi−Z

L X H H L X X X NA L to H Deselect Hi−Z

L H L L X X X L External L to H Begin read Q

L H L L X X X H External L to H Begin read Hi−Z

L H L H L X H L External L to H Begin read Q

L H L H L X H H External L to H Begin read Hi−Z

XXXHHL H L Next L to HContinue readQ

XXXHHL H H Next L to HContinue readHi−Z

XXXHHH H L Current L to HSuspend readQ

XXXHHH H H Current L to HSuspend readHi−Z

HXXXHL H L Next L to HContinue readQ

HXXXHL H H Next L to HContinue readHi−Z

HXXXHH H L Current L to HSuspend readQ

HXXXHH H H Current L to HSuspend readHi−Z

L H L H L X L X External L to H Begin write D3

3 For write operation following a READ,

must be high before the input data set up time and held high throughout the input hold time

4 ZZ pin is always Low.

XXXHHL L X Next L to HContinue writeD

HXXXHL L X Next L to HContinue writeD

XXXHHH L X Current L to HSuspend writeD

HXXXHH L X Current L to HSuspend writeD

AS7C251MPFS32A

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Absolute maximum ratings

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 outside those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions may affect

reliability.

Recommended operating conditions

Parameter Symbol Min Max Unit

Power supply voltage relative to GND VDD, VDDQ –0.3 +3.6 V

Input voltage relative to GND (input pins) VIN –0.3 VDD + 0.3 V

Input voltage relative to GND (I/O pins) VIN –0.3 VDDQ + 0.3 V

Power dissipation Pd–1.8W

Short circuit output current IOUT – 20 mA

Storage temperature Tstg –65 +150 oC

Temperature under bias Tbias –65 +135 oC

Parameter Symbol Min Nominal Max Unit

Supply voltage for inputs VDD 2.375 2.5 2.625 V

Supply voltage for I/O VDDQ 2.375 2.5 2.625 V

Ground supply Vss 0 0 0 V

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AS7C251MPFS32A

AS7C251MPFS36A

DC electrical characteristics

† LBO and ZZ pins have an internal pull-up or pull-down, and input leakage = ±10 µA.

*VIH max < VDD +1.5V for pulse width less than 0.2 X tCYC

**VIL min = -1.5 for pulse width less than 0.2 X tCYC

IDD operating conditions and maximum limits

Parameter Sym Conditions Min Max Unit

Input leakage current† |ILI|V

DD = Max, 0V < VIN < VDD -2 2 µA

Output leakage current |ILO|OE ≥ VIH, VDD = Max, 0V < VOUT < VDDQ -2 2 µA

Input high (logic 1) voltage VIH

Address and control pins 1.7*VDD+0.3 V

I/O pins 1.7*VDDQ+0.3 V

Input low (logic 0) voltage VIL

Address and control pins -0.3** 0.7 V

I/O pins -0.3** 0.7 V

Output high voltage VOH IOH = –4 mA, VDDQ = 2.375V 1.7 – V

Output low voltage VOL IOL = 8 mA, VDDQ = 2.625V – 0.7 V

Parameter Sym Conditions -200 -166 -133 Unit

Operating power supply current1

1 ICC given with no output loading. ICC increases with faster cycle times and greater output loading.

ICC

CE0 < VIL, CE1 > VIH, CE2 < VIL, f = fMax,

IOUT = 0 mA, ZZ < VIL

450 400 350 mA

Standby power supply current

ISB

All VIN ≤ 0.2V or >

– 0.2V,

Deselected,

f = fMax, ZZ < VIL

170 150 140

ISB1 Deselected, f = 0, ZZ < 0.2V,

all VIN ≤ 0.2V or ≥ VDD – 0.2V 90 90 90

ISB2

Deselected, f = f

Max

, ZZ

≥

– 0.2V,

all VIN ≤ VIL or ≥ VIH 80 80 80

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Timing characteristics over operating range

Snooze Mode Electrical Characteristics

Parameter Sym

–200 –166 -133

Unit Notes1

1 See “Notes” on page 16.

Min Max Min Max Min Max

Clock frequency fMax – 200 – 166 – 133 MHz

Cycle time tCYC 5 – 6 – 7.5 – ns

Clock access time tCD – 3.1 – 3.5 – 3.8 ns

Output enable low to data valid tOE – 3.1 – 3.5 – 3.8 ns

Clock high to output low Z tLZC 0 – 0 – 0 – ns 2,3,4

Data output invalid from clock high tOH 1.5 – 1.5 – 1.5 – ns 2

Output enable low to output low Z tLZOE 0 – 0 – 0 – ns 2,3,4

Output enable high to output high Z tHZOE – 3.0 – 3.4 – 3.8 ns 2,3,4

Clock high to output high Z tHZC – 3.0 – 3.4 – 3.8 ns 2,3,4

Output enable high to invalid output tOHOE 0–0 – 0 – ns

Clock high pulse width tCH 2.0 – 2.4 – 2.4 – ns 5

Clock low pulse width tCL 2.0 – 2.4 – 2.4 – ns 5

Address setup to clock high tAS 1.4 – 1.5 – 1.5 – ns 6

Data setup to clock high tDS 1.4 – 1.5 – 1.5 – ns 6

Write setup to clock high tWS 1.4 – 1.5 – 1.5 – ns 6,7

Chip select setup to clock high tCSS 1.4 – 1.5 – 1.5 – ns 6,8

Address hold from clock high tAH 0.4 – 0.5 – 0.5 – ns 6

Data hold from clock high tDH 0.4 – 0.5 – 0.5 – ns 6

Write hold from clock high tWH 0.4 – 0.5 – 0.5 – ns 6,7

Chip select hold from clock high tCSH 0.4 – 0.5 – 0.5 – ns 6,8

ADV setup to clock high tADVS 1.4 – 1.5 – 1.5 – ns 6

ADSP setup to clock high tADSPS 1.4 – 1.5 – 1.5 – ns 6

ADSC setup to clock high tADSCS 1.4 – 1.5 – 1.5 – ns 6

ADV hold from clock high tADVH 0.4 – 0.5 – 0.5 – ns 6

ADSP hold from clock high tADSPH 0.4 – 0.5 – 0.5 – ns 6

ADSC hold from clock high tADSCH 0.4 – 0.5 – 0.5 – ns 6

Description Conditions Symbol Min Max Units

Current during Snooze Mode ZZ > VIH ISB2 80 mA

ZZ active to input ignored tPDS 2cycle

ZZ inactive to input sampled tPUS 2cycle

ZZ active to SNOOZE current tZZI 2cycle

ZZ inactive to exit SNOOZE current tRZZI 0

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AS7C251MPFS36A

Key to switching waveforms

Timing waveform of read cycle

Note: Ý = XOR when LBO = high/no connect; Ý = ADD when LBO = low. BW[a:d] is don’t care.

don’t careFalling inputRising input Undefined

CE1

CYC

ADSPS

ADSPH

ADVS

CLK

ADSP

ADSC

Address

GWE, BWE

CE0, CE2

ADV

Dout

CSS

HZC

ADVH

HZOE

ADSCS

ADSCH

LOAD NEW ADDRESS

ADV inserts wait states

Q(A2Ý10)

Q(A2Ý11)

Q(A3)

Q(A2)

Q(A2Ý01) Q(A3Ý01) Q(A3Ý10)

Q(A1)

A2A1 A3

LZOE

CSH

Read

Q(A1)

Suspend

Read

Q(A1)

Read

Q(A2)

Burst

Read

Q(A 2Ý01

)

Read

Q(A3) DSEL

Burst

Read

Q(A 2Ý10

)

Suspend

Read

Q(A 2Ý10

)

Burst

Read

Q(A 2Ý11

)

Burst

Read

Q(A 3Ý01

)

Burst

Read

Q(A 3Ý10

)

Burst

Read

Q(A 3Ý11

)

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Timing waveform of write cycle

Note: Ý = XOR when LBO = high/no connect; Ý = ADD when LBO = low.

CYC

ADSPS

ADSPH

ADSCS

ADSCH

CSS

ADVS

CLK

ADSP

ADSC

Address

BWE

CE0, CE2

ADV

Din

CSH

ADVH

D(A2Ý01)

D(A2Ý10) D(A3)D(A2) D(A2Ý01) D(A3Ý01) D(A3Ý10)

D(A1) D(A2Ý11)

ADV SUSPENDS BURST

ADSC LOADS NEW ADDRESS

A1 A2 A3

CE1

BW[a:d]

Read

Q(A1) Sus-

pend

Write

D(A1)

Read

Q(A2)

Suspend

Write

D(A 2

)

ADV

Burst

Write

D(A 2Ý01

)

Suspend

Write

D(A 2Ý01

)

ADV

Burst

Write

D(A 2Ý10

)

Write

D(A 3

)

Burst

Write

D(A 3Ý01

)

ADV

Burst

Write

D(A 2Ý11

)

ADV

Burst

Write

D(A 3Ý10

)

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Timing waveform of read/write cycle (ADSP Controlled; ADSC High)

Note: Ý = XOR when LBO = high/no connect; Ý = ADD when LBO = low.

CYC

ADSPS

ADSPH

ADVS

CLK

ADSP

Address

GWE

CE0, CE2

ADV

Din

Dout

ADVH

LZOE

LZC

Q(A1)

Q(A3Ý01)

D(A2)

Q(A3)

Q(A3Ý10) Q(A3Ý11)

A1 A2 A3

CE1

HZOE

DSEL Suspend

Read

Q(A1)

Read

Q(A1)

Suspend

Write

D(A 2

)

ADV

Burst

Read

Q(A 3Ý01

)

ADV

Burst

Read

Q(A 3Ý10

)

ADV

Burst

Read

Q(A 3Ý11

)

Read

Q(A2)

Read

Q(A3)

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Timing waveform of read/write cycle(ADSC controlled, ADSP = HIGH)

CYC

ADSCH

CLK

ADSC

ADDRESS A2

ADSCS

A3 A4 A6

A5 A7 A8 A9

GWE

CSH

CE0,CE2

CSS

ADV

LZOE

HZOE

Q(A1) Q(A2) Q(A3) Q(A4) Q(A8) Q(A9)

LZOE

D(A6) D(A7)

D(A5)

Dout

Din

READ

Q(A1)

READ

Q(A2)

READ

Q(A3)

READ

Q(A4)

WRITE

D(A5)

WRITE

D(A6)

WRITE

D(A7)

READ

Q(A8)

READ

Q(A9)

CE1

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Timing waveform of power down cycle

CYC

ADSPS

CLK

ADSP

ADDRESS A1

ADSPS

GWE

CSH

CE0,CE2

CSS

ADV

LZOE

HZOE

Q(A1)

D(A2(

01))

D(A2)

Dout

Din

ADSC

HZC

PDS

ZZ Setup Cycle

PUS

ZZ Recovery Cycle Normal Operation Mode

CE1

READ

Q(A1)

SUSPEND

READ

Q(A1)

CON-

TINUE

WRITE

D(A2 Ý01)

SUSPEND

WRITE

D(A2)

READ

Q(A2)

Sleep

SB2

State

ZZI

RZZI

supply

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AC test conditions

Notes

1 For test conditions, see “AC test conditions”, Figures A, B, and C.

2 This parameter is measured with output load condition in Figure C.

3 This parameter is sampled but not 100% tested.

HZOE is less than tLZOE, and tHZC is less than tLZC at any given temperature and voltage.

CH is measured as high if above VIH, and tCL is measured as low if below VIL.

6 This is a synchronous device. All addresses must meet the specified setup and hold times for all rising edges of CLK. All other synchronous inputs must

meet the setup and hold times for all rising edges of CLK when chip is enabled.

7 Write refers to

GWE

BWE

, and

BW[a:d].

8 Chip select refers to

CE0

CE1

, and

CE2

= 50

Ω

OUT

Ω

Figure B: Output load (A)

30 pF*

Figure A: Input waveform

10%

90%

GND

90%

10%

+2.5V

• Output load: For tLZC, tLZOE, tHZOE, tHZC, see Figure C. For all others, see Figure B.

• Input pulse level: GND to 2.5V. See Figure A.

• Input rise and fall time (measured at 0.25V and 2.25V): 2 ns. See Figure A.

• Input and output timing reference levels: 1.25V.

= V

DDQ

Thevenin equivalent:

353

Ω/1538Ω

5 pF*

319

Ω/1667Ω

OUT

GND

Figure C: Output load(B)

*including scope

and jig capacitance

+2.5V

2/14/05, v.1.3 Alliance Semiconductor 17 of 19

AS7C251MPFS32A

AS7C251MPFS36A

Package dimensions

100-pin quad flat pack (TQFP)

TQFP

Min Max

A1 0.05 0.15

A2 1.35 1.45

b 0.22 0.38

c 0.09 0.20

D 13.90 14.10

E 19.90 20.10

e 0.65 nominal

Hd 15.85 16.15

He 21.80 22.20

L 0.45 0.75

L1 1.00 nominal

α0° 7°

Dimensions in millimeters

A1 A2

He E

AS7C251MPFS32A

AS7C251MPFS36A

2/14/05, v.1.3 Alliance Semiconductor 18 of 19

Ordering information

Note:

Add suffix ‘N’ to the above part numbers for lead free parts (Ex AS7C251MPFS32A-200TQCN)

Part numbering guide

1. Alliance Semiconductor SRAM prefix

2. Operating voltage: 25 = 2.5V

3. Organization: 1M = 1Meg

4. Pipelined mode

5. Deselect: S = single cycle deselect

6. Organization: 32 = x 32; 36 = x 36

7. Production version: A = first production version

8. Clock speed (MHz)

9. Package type: TQ = TQFP

10. Operating temperature: C = commercial (

C to 70

C); I = industrial (

-40

C to 85

11. N = Lead Free Part

Package & Width 200 MHz 166 MHz 133 MHz

TQFP x32 AS7C251MPFS32A-200TQC AS7C251MPFS32A-166TQC AS7C251MPFS32A-133TQC

AS7C251MPFS32A-200TQI AS7C251MPFS32A-166TQI AS7C251MPFS32A-133TQI

TQFP x36 AS7C251MPFS36A-200TQC AS7C251MPFS36A-166TQC AS7C251MPFS36A-133TQC

AS7C251MPFS36A-200TQI AS7C251MPFS36A-166TQI AS7C251MPFS36A-133TQI

AS7C 25 1M PF S32/36 A–XXX TQ C/I X

45678

91011

Alliance Semiconductor Corporation

2575, Augustine Drive,

Santa Clara, CA 95054

Tel: 408 - 855 - 4900

Fax: 408 - 855 - 4999

www.alsc.com

Part Number: AS7C251MPFS32A /

Document Version: v.1.3

ance. All other brand and product names may be the trademarks of their respective companies. Alliance reserves the right to make changes to this document and its products

at any time without notice. Alliance assumes no responsibility for any errors that may appear in this document. The data contained herein represents Alliance's best data and/

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AS7C251MPFS32A

AS7C251MPFS36A