December 2004 AS7C251MPFS18A ® 2.5V 1M x 18 pipelined burst synchronous SRAM Features • • • • • • • • Organization: 1,048,576 x18 bits Fast clock speeds to 166 MHz Fast clock to data access: 3.5/3.8 ns Fast OE access time: 3.5/3.8 ns Fully synchronous register-to-register operation Single-cycle deselect Asynchronous output enable control Available 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 LBO CLK ADV ADSC ADSP CLK CS CLR 20 A[19:0] Burst logic Q D CS Address 20 1M x 18 Memory array 18 20 register CLK 18 18 GWE BWb D DQb BWE CLK D DQa Q Q Byte Write registers BWa 2 Byte Write registers CLK CE0 CE1 CE2 D Enable register OE Q CE CLK D ZZ Power down Enable delay register Input registers Output registers CLK CLK Q CLK 18 OE DQ[a,b] Selection guide -166 -133 Units 6 7.5 ns Maximum clock frequency 166 133 MHz Maximum clock access time 3.5 3.8 ns Maximum operating current 290 270 mA Maximum standby current 85 75 mA Maximum CMOS standby current (DC) 40 40 mA Minimum cycle time 12/23/04, v. 2.2 Alliance Semiconductor 1 of 19 Copyright © Alliance Semiconductor. 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AS7C251MPFS18A ® 16 Mb 2.5V Synchronous SRAM products list1,2 Org 1MX18 512KX32 Part Number AS7C251MPFS18A AS7C25512PFS32A Mode PL-SCD PL-SCD Speed 166/133 MHz 166/133 MHz 512KX36 1MX18 512KX32 512KX36 1MX18 512KX32 512KX36 1MX18 512KX32 AS7C25512PFS36A AS7C251MPFD18A AS7C25512PFD32A AS7C25512PFD36A AS7C251MFT18A AS7C25512FT32A AS7C25512FT36A AS7C251MNTD18A AS7C25512NTD32A PL-SCD PL-DCD PL-DCD PL-DCD FT FT FT NTD-PL NTD-PL 166/133 MHz 166/133 MHz 166/133 MHz 166/133 MHz 7.5/8.5/10 ns 7.5/8.5/10 ns 7.5/8.5/10 ns 166/133 MHz 166/133 MHz 512KX36 1MX18 512KX32 512KX36 AS7C25512NTD36A AS7C251MNTF18A AS7C25512NTF32A AS7C25512NTF36A NTD-PL NTD-FT NTD-FT NTD-FT 166/133 MHz 7.5/8.5/10 ns 7.5/8.5/10 ns 7.5/8.5/10 ns 1 Core Power Supply: VDD = 2.5V + 0.125V 2 I/O Supply Voltage: VDDQ = 2.5V + 0.125V PL-SCD PL-DCD FT NTD1-PL NTD-FT : : : : : Pipelined Burst Synchronous SRAM - Single Cycle Deselect Pipelined Burst Synchronous SRAM - Double Cycle Deselect Flow-through Burst Synchronous SRAM Pipelined Burst Synchronous SRAM with NTDTM Flow-through Burst Synchronous SRAM with NTDTM 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. 12/23/04, v. 2.2 Alliance Semiconductor 2 of 19 AS7C251MPFS18A ® Pin designations NC NC NC TQFP 14 x 20mm 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 A NC NC VDDQ VSSQ NC DQPa DQa7 DQa6 VSSQ VDDQ DQa5 DQa4 VSS NC VDD ZZ DQa3 DQa2 VDDQ VSSQ DQa1 DQa0 NC NC VSSQ VDDQ NC NC NC LBO A A A A A1 A0 NC NC VSS VDD A A A A A A A A A 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 VDDQ VSSQ NC NC DQb0 DQb1 VSSQ VDDQ DQb2 DQb3 NC VDD NC VSS DQb4 DQb5 VDDQ VSSQ DQb6 DQb7 DQPb NC VSSQ VDDQ NC NC NC 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 30 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81 A A CE0 CE1 NC NC BWb BWa CE2 VDD VSS CLK GWE BWE OE ADSC ADSP ADV A A Pin configuration for 100-pin TQFP 12/23/04, v. 2.2 Alliance Semiconductor 3 of 19 AS7C251MPFS18A ® Functional description The AS7C251MPFS18A is a high-performance CMOS 16-Mbit synchronous Static Random Access Memory (SRAM) device organized as 1,048,576 words X 18 bits and incorporates a two-stage register-register pipeline for highest frequency on any given technology. Fast cycle times of 6/7.5 ns with clock access times (tCD) of 3.5/3.8 ns enable 166 MHz and 133 MHz 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 is 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 it 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 18 bits regardless of the state of individual BW[a,b] 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. 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 AS7C251MPFS18A family operates from a core 2.5V power supply. These devices are available in a 100-pin TQFP package. TQFP capacitance Parameter Input capacitance I/O capacitance Symbol CIN* CI/O* Test conditions VIN = 0V VOUT = 0V Min - Max 5 7 Unit pF pF * Guaranteed not tested TQFP thermal resistance Description Thermal resistance (junction to ambient)1 Thermal resistance (junction to top of case)1 Conditions Test conditions follow standard test methods and procedures for measuring thermal impedance, per EIA/JESD51 1–layer Symbol θJA θJA Typical 40 22 Units °C/W °C/W 4–layer θJC 8 °C/W 1 This parameter is sampled 12/23/04, v. 2.2 Alliance Semiconductor 4 of 19 AS7C251MPFS18A ® Signal descriptions Signal 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] I/O SYNC Data. Driven as output when the chip is enabled and when OE is active. CE0 I SYNC 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 I SYNC 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 bus 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 I SYNC Global write enable. Asserted LOW to write all 32/36 and 18 bits. When HIGH, BWE and BW[a,b] control write enable. BWE I SYNC Byte write enable. Asserted LOW with GWE HIGH to enable effect of BW[a,b] inputs. BW[a,b] I SYNC Write enables. Used to control write of individual bytes when GWE is HIGH and BWE is LOW. If any of BW[a,b] is active with GWE HIGH and BWE LOW, the cycle is a write cycle. If all BW[a,b] are inactive, the cycle is a read cycle. OE I ASYNC Asynchronous output enable. I/O pins are driven when OE is active and the chip is in read mode. LBO I STATIC 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 Sleep. Places device in LOW power mode; data is retained. Connect to GND if unused. NC - - No connect 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. 12/23/04, v. 2.2 Alliance Semiconductor 5 of 19 AS7C251MPFS18A ® Write enable truth table (per byte) Function GWE BWE BWa BWb L X X X H L L L Write byte a H L L H Write byte b H L H L H H X X H L H H Write all bytes (a, b) Read Key: X = don’t care; L = low; H = high; BWE, BWn = internal write signal Asynchronous Truth Table Operation Snooze mode Read Write Deselected ZZ H L L L L OE X L H X X I/O Status High-Z Dout High-Z Din, High-Z High-Z 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 Interleaved burst address (LBO = 1) A1 A0 A1 A0 A1 A0 Starting Address First Increment Second Increment Third Increment 12/23/04, v. 2.2 00 01 10 11 01 00 11 10 10 11 00 01 Linear burst address (LBO = 0) A1 A0 A1 A0 A1 A0 A1 A0 11 10 01 00 Starting Address First Increment Second Increment Third Increment Alliance Semiconductor 00 01 10 11 01 10 11 10 10 11 00 01 A1 A0 11 00 01 10 6 of 19 AS7C251MPFS18A ® Synchronous truth table[4] CE01 CE1 CE2 ADSP ADSC H L L L L L L L L X X X X H H H H L X H X H X L L X X H H H H X X X X X X X X H X X X X X X X H H L L L L X X X X X X X X L X X X X X L H L H L L H H H H H H X X X X H H X H X L X L X L X X L L H H H H H H H H L H H H H ADV WRITE[2] X X X X X X X X X L L H H L L H H X L L H H X X X X X X X H H H H H H H H H H L L L L L OE Address accessed CLK Operation DQ X X X X X L H L H L H L H L H L H X X X X X NA NA NA NA NA External External External External Next Next Current Current Next Next Current Current External Next Next Current Current L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H L to H Deselect Deselect Deselect Deselect Deselect Begin read Begin read Begin read Begin read Continue read Continue read Suspend read Suspend read Continue read Continue read Suspend read Suspend read Begin write Continue write Continue write Suspend write Suspend write Hi−Z Hi−Z Hi−Z Hi−Z Hi−Z Q Hi−Z Q Hi−Z Q Hi−Z Q Hi−Z Q Hi−Z Q Hi−Z D3 D D D D 1 X = don’t care, L = low, H = high 2 For WRITE, L means any one or more byte write enable signals (BWa or BWb) and BWE are LOW or GWE is LOW. WRITE = HIGH for all BWx, BWE, GWE HIGH. See "Snooze Mode," on page 5 for more information. 3 For write operation following a READ, OE must be HIGH before the input data set up time and held HIGH throughout the input hold time 4 ZZ pin is always Low. 12/23/04, v. 2.2 Alliance Semiconductor 7 of 19 AS7C251MPFS18A ® Absolute maximum ratings Parameter Symbol Min Max Unit 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 – 1.8 W DC output current IOUT – 20 mA mA Storage temperature Tstg –65 +150 oC Temperature under bias Tbias –65 +135 oC Power supply voltage relative to GND Note: Stresses greater than those listed in this table 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 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 Vss 0 0 0 V Ground supply 12/23/04, v. 2.2 Alliance Semiconductor 8 of 19 AS7C251MPFS18A ® DC electrical characteristics Parameter Sym Conditions Min Max Unit current† |ILI| VDD = 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 Input leakage † LBO and ZZ pins have an internal pull-up or pull-down, and input leakage = ±10 µA. *V max < VDD +1.5V for pulse width less than 0.2 X t IH CYC ** VIL min = -1.5 for pulse width less than 0.2 X tCYC IDD operating conditions and maximum limits Parameter Operating power supply current1 Sym ICC ISB Standby power supply current Conditions CE0 < VIL, CE1 > VIH, CE2 < VIL, f = fMax, IOUT = 0 mA, ZZ < VIL All VIN ≤ 0.2V or > VDD – 0.2V, Deselected, f = fMax, ZZ < VIL -166 -133 Unit 290 270 mA 85 75 ISB1 Deselected, f = 0, ZZ < 0.2V, all VIN ≤ 0.2V or ≥ VDD – 0.2V 40 40 ISB2 Deselected, f = fMax, ZZ ≥ VDD – 0.2V, all VIN ≤ VIL or ≥ VIH 40 40 mA 1 ICC given with no output loading. ICC increases with faster cycle times and greater output loading. 12/23/04, v. 2.2 Alliance Semiconductor 9 of 19 AS7C251MPFS18A ® Timing characteristics over operating range –166 Parameter –133 Notes1 Sym Min Max Min Max Unit Clock frequency fMax – 166 – 133 MHz Cycle time tCYC 6 – 7.5 – ns Clock access time tCD – 3.5 – 3.8 ns Output enable low to data valid tOE – 3.5 – 3.8 ns Clock high to output low Z tLZC 0 – 0 – ns 2,3,4 Data output invalid from clock high tOH 1.5 – 1.5 – ns 2 Output enable low to output low Z tLZOE 0 – 0 – ns 2,3,4 Output enable high to output high Z tHZOE – 3.5 - 3.8 ns 2,3,4 Clock high to output high Z tHZC – 3.5 - 3.8 ns 2,3,4 tOHOE 0 – 0 – ns Clock high pulse width tCH 2.4 – 2.4 – ns 5 Clock low pulse width tCL 2.3 – 2.4 – ns 5 Address setup to clock high tAS 1.5 – 1.5 – ns 6 Data setup to clock high tDS 1.5 – 1.5 – ns 6 Write setup to clock high tWS 1.5 – 1.5 – ns 6,7 Chip select setup to clock high tCSS 1.5 – 1.5 – ns 6,8 Address hold from clock high tAH 0.5 – 0.5 – ns 6 Data hold from clock high tDH 0.5 – 0.5 – ns 6 Write hold from clock high tWH 0.5 – 0.5 – ns 6,7 Chip select hold from clock high tCSH 0.5 – 0.5 – ns 6,8 ADV setup to clock high tADVS 1.5 – 1.5 – ns 6 ADSP setup to clock high tADSPS 1.5 – 1.5 – ns 6 ADSC setup to clock high tADSCS 1.5 – 1.5 – ns 6 ADV hold from clock high tADVH 0.5 – 0.5 – ns 6 ADSP hold from clock high tADSPH 0.5 – 0.5 – ns 6 ADSC hold from clock high tADSCH 0.5 – 0.5 – ns 6 Output enable high to invalid output 1 See “Notes” on page 16. Snooze Mode Electrical Characteristics Description Current during Snooze Mode ZZ active to input ignored ZZ inactive to input sampled ZZ active to SNOOZE current ZZ inactive to exit SNOOZE current 12/23/04, v. 2.2 Conditions Symbol ZZ > VIH ISB2 tPDS tPUS tZZI tRZZI Alliance Semiconductor Min Max Units 40 mA cycle cycle cycle cycle 2 2 2 0 10 of 19 AS7C251MPFS18A ® Key to switching waveforms Rising input Falling input don’t care Undefined Timing waveform of read cycle tCYC tCL tCH CLK tADSPS tADSPH ADSP tADSCS tADSCH ADSC LOAD NEW ADDRESS tAH tAS A1 Address A2 tWS A3 tWH GWE, BWE tCSS tCSH CE0, CE2 CE1 tADVS tADVH ADV ADV inserts wait states OE tOE tHZOE tLZOE Dout Q(A1) Read Q(A1) Suspend Read Q(A1) Read Q(A2) tCD tHZC tOH Q(A2) Q(A2Ý01) Q(A2Ý10) Q(A2Ý11) Q(A3) Q(A3Ý01) Q(A3Ý10) Burst Burst Read Suspend Burst Burst Burst Burst Read Read Q(A3) Read Read Read Read Read Q(A 2Ý01) Q(A 2Ý10) Q(A 2Ý10) Q(A 2Ý11) Q(A 3Ý01) Q(A 3Ý10) Q(A 3Ý11) DSEL Note: Ý = XOR when LBO = high/no connect; Ý = ADD when LBO = low. BW[a:d] is don’t care. 12/23/04, v. 2.2 Alliance Semiconductor 11 of 19 AS7C251MPFS18A ® Timing waveform of write cycle tCYC tCL tCH CLK tADSPS tADSPH ADSP tADSCS tADSCH ADSC ADSC LOADS NEW ADDRESS tAS tAH A1 Address A3 A2 tWS tWH tADVS tADVH tDS tDH BWE BW[a:b] tCSS tCSH CE0, CE2 CE1 ADV SUSPENDS BURST ADV OE Din D(A1) Read Q(A1) Suspend Write D(A1) D(A2) Read Q(A2) D(A2Ý01) Suspend Write D(A 2) D(A2Ý01) D(A2Ý10) D(A2Ý11) D(A3) ADV ADV ADV Suspend Burst Burst Burst Write Write Write D(A 2Ý01) Write D(A 2Ý01) D(A 2Ý10) D(A 2Ý11) D(A3Ý01) Write D(A 3) D(A3Ý10) Burst Write D(A 3Ý01) ADV Burst Write D(A 3Ý10) Note: Ý = XOR when LBO = high/no connect; Ý = ADD when LBO = low. 12/23/04, v. 2.2 Alliance Semiconductor 12 of 19 AS7C251MPFS18A ® Timing waveform of read/write cycle (ADSP Controlled; ADSC High) tCYC tCL tCH CLK tADSPH tADSPS ADSP tAH tAS A2 A1 Address A3 tWH tWS GWE CE0, CE2 CE1 tADVH tADVS ADV OE tDS tDH Din D(A2) tOE tCD tLZC Dout DSEL Read Q(A1) tHZOE Q(A1) Suspend Read Q(A1) tOH tLZOE Q(A3) Read Q(A2) Suspend Write D(A 2) Read Q(A3) ADV Burst Read Q(A 3Ý01) Q(A3Ý01) ADV Burst Read Q(A 3Ý10) Q(A3Ý10) Q(A3Ý11) ADV Burst Read Q(A 3Ý11) Note: Ý = XOR when LBO = high/no connect; Ý = ADD when LBO = low. 12/23/04, v. 2.2 Alliance Semiconductor 13 of 19 AS7C251MPFS18A ® Timing waveform of read/write cycle(ADSC controlled, ADSP = HIGH) tCYC tCL tCH CLK tADSCS tADSCH ADSC tAS A1 ADDRESS A5 A4 A3 A2 A7 A6 tWS tAH A8 A9 tWH GWE tCSS tCSH CE0,CE2 CE1 ADV OE tOE tLZOE Q(A1) Dout tLZOE tHZOE Q(A2) Q(A3) Q(A8) Q(A4) D(A5) READ Q(A1) 12/23/04, v. 2.2 READ Q(A2) READ Q(A3) READ Q(A4) Q(A9) tDH tDS Din tOH D(A6) D(A7) WRITE WRITE WRITE D(A6) D(A7) D(A5) Alliance Semiconductor READ Q(A8) READ Q(A9) 14 of 19 AS7C251MPFS18A ® Timing waveform of power down cycle tCH tCYC tCL CLK tADSPS tADSPS ADSP ADSC A2 A1 ADDRESS tWH tWS GWE tCSS tCSH CE0,CE2 CE1 ADV OE tOE Din tLZOE tHZOE D(A2) D(A2(Ý01)) tHZC Dout Q(A1) tPUS tPDS ZZ Recovery Cycle ZZ Normal Operation Mode ZZ Setup Cycle tZZI tRZZI Isupply ISB2 READ SUSPEND Q(A1) READ Q(A1) 12/23/04, v. 2.2 Sleep State Alliance Semiconductor READ SUSPEND CONQ(A2) WRITE TINUE D(A2) WRITE D(A2 Ý01) 15 of 19 AS7C251MPFS18A ® AC test conditions • 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. Thevenin equivalent: • Input rise and fall time (measured at 0.25V and 2.25V): 2 ns. See Figure A. +2.5V • Input and output timing reference levels: 1.25V. +2.5V 90% 10% GND 90% 10% Figure A: Input waveform DOUT Z0 = 50Ω 50Ω VL = VDDQ/2 30 pF* Figure B: Output load (A) 319Ω/1667Ω DOUT 353Ω/1538Ω 5 pF* GND *including scope and jig capacitance Figure C: Output load(B) Notes 1 2 3 4 5 6 7 8 For test conditions, see “AC Test Conditions”, Figures A, B, and C. This parameter is measured with output load condition in Figure C. This parameter is sampled but not 100% tested. tHZOE is less than tLZOE, and tHZC is less than tLZC at any given temperature and voltage. tCH is measured as high above VIH, and tCL is measured as low below VIL. 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. Write refers to GWE, BWE, and BW[a,b]. Chip select refers to CE0, CE1, and CE2. 12/23/04, v. 2.2 Alliance Semiconductor 16 of 19 AS7C251MPFS18A ® Package dimensions 100-pin TQFP (quad flat pack) TQFP Hd 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 α D c L1 L b A1 A2 e α He E 1.00 nominal 0° 7° Dimensions in millimeters 12/23/04, v. 2.2 Alliance Semiconductor 17 of 19 AS7C251MPFS18A ® Ordering information Package &Width TQFP x18 –166 –133 AS7C251MPFS18A-166TQC AS7C251MPFS18A-133TQC AS7C251MPFS18A-166TQI AS7C251MPFS18A-133TQI Note: Add ‘N’ to the above part numbers for Lead Free Parts (Ex. AS7C251MPFS18A-166TQCN) Part numbering guide AS7C 25 1M PF S 18 A –XXX TQ C/I X 1 2 3 4 5 6 7 8 9 10 11 1. Alliance Semiconductor SRAM prefix 2. Operating voltage: 25 = 2.5V 3. Organization: 1M 4. Pipelined mode 5. Deselect: S = single cycle deselect 6. Organization: 18 = x18 7. Production version: A = first production version 8. Clock speed (MHz) 9. Package type: TQ = TQFP 10. Operating temperature: C = commercial (0° C to 70° C); I = industrial (-40° C to 85° C) 11. N = Lead Free Part 12/23/04, v. 2.2 Alliance Semiconductor 18 of 19 AS7C251MPFS18A ® ® Alliance Semiconductor Corporation 2575, Augustine Drive, Santa Clara, CA 95054 Tel: 408 - 855 - 4900 Fax: 408 - 855 - 4999 www.alsc.com Copyright © Alliance Semiconductor All Rights Reserved Part Number: AS7C251MPFS18A Document Version: v. 2.2 © Copyright 2003 Alliance Semiconductor Corporation. All rights reserved. Our three-point logo, our name and Intelliwatt are trademarks or registered trademarks of Alliance. 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/or estimates at the time of issuance. Alliance reserves the right to change or correct this data at any time, without notice. If the product described herein is under development, significant changes to these specifications are possible. The information in this product data sheet is intended to be general descriptive information for potential customers and users, and is not intended to operate as, or provide, any guarantee or warrantee to any user or customer. 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