3.3V CMOS FAST SRAM WITH 2.5V COMPATIBLE INPUTS 256K (32K x 8-BIT) IDT71V256SB Integrated Device Technology, Inc. FEATURES DESCRIPTION • Ideal for high-performance processor secondary cache • Fast access times: — 12/15/20ns • Inputs are 2.5V and LVTTL compatible: VIH = 1.8V • Outputs are LVTTL compatible • Low standby current (maximum): — 2mA full standby • Small packages for space-efficient layouts: — 28-pin 300 mil SOJ — 28-pin TSOP Type I • Produced with advanced high-performance CMOS technology • Single 3.3V(±0.3V) power supply The IDT71V256SB is a 262,144-bit high-speed static RAM organized as 32K x 8. The improved VIH (1.8V) makes the inputs compatible with 2.5V logic levels. The IDT71V256SB is otherwise identical to the IDT71V256SA. The IDT71V256SB has outstanding low power characteristics while at the same time maintaining very high performance. Address access times of as fast as12 ns are ideal for tag SRAM in secondary cache designs. When power management logic puts the IDT71V256SB in standby mode, its very low power characteristics contribute to extended battery life. By taking CS HIGH, the SRAM will automatically go to a low power standby mode and will remain in standby as long as CS remains HIGH. Furthermore, under full standby mode (CS at CMOS level, f=0), power consumption is guaranteed to always be less than 6.6mW and typically will be much smaller. The IDT71V256SB is packaged in 28-pin 300 mil SOJ and 28-pin300 mil TSOP Type I packaging. FUNCTIONAL BLOCK DIAGRAM A0 VCC 262,144 BIT MEMORY ARRAY ADDRESS DECODER GND A14 I/O0 I/O CONTROL INPUT DATA CIRCUIT I/O7 CS OE WE CONTROL CIRCUIT 3770 drw 01 The IDT logo is a registered trademark of Integrated Device Technology, Inc. COMMERCIAL TEMPERATURE RANGES 1997 Integrated Device Technology, Inc. JANUARY 1997 7.?? 3770/1 1 IDT71V256SB 3.3V CMOS STATIC RAM WITH 2.5V COMPATIBLE INPUTS 256K (32K x 8-BIT) ABSOLUTE MAXIMUM RATINGS(1) PIN CONFIGURATIONS A14 A12 A7 A6 A5 A4 A3 A2 A1 A0 I/O0 I/O1 I/O2 GND 1 28 VCC 2 27 WE 3 26 4 25 5 24 23 A13 A8 A9 A11 6 SO28-5 7 22 OE 8 21 A10 9 20 CS 10 19 11 18 12 17 13 16 14 15 SOJ TOP VIEW Symbol I/O7 I/O6 I/O5 I/O4 I/O3 OE 22 21 A10 23 20 CS 24 19 25 18 26 17 WE 27 VCC A14 A12 A7 A6 A5 A4 A3 28 I/O7 I/O6 I/O5 I/O4 I/O3 GND I/O2 I/O1 I/O0 A0 A1 A2 16 15 SO28-8 14 2 13 3 12 4 11 5 10 6 9 7 8 Terminal Voltage with Respect to GND VTERM(3) Terminal Voltage with Respect to GND Com’l. Unit –0.5 to +4.6 V –0.5 to VCC+0.5 V 0 to +70 °C Temperature Under Bias –55 to +125 °C Storage Temperature –55 to +125 °C TA Operating Temperature TBIAS TSTG PT Power Dissipation 1.0 W IOUT DC Output Current 50 mA CAPACITANCE (TA = +25°C, f = 1.0MHz, SOJ package) Parameter(1) Symbol 3770 drw 03 TSOP TOP VIEW Rating VTERM(2) NOTES: 3770 tbl 03 1. 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 extended periods may affect reliability. 2. Vcc terminals only. 3. Input, Output, and I/O terminals; 4.6V maximum. 3770 drw 02 A11 A9 A8 A13 1 COMMERCIAL TEMPERATURE RANGE CIN Input Capacitance COUT Output Capacitance Conditions Max. Unit VIN = 3dV 6 pF VOUT = 3dV 7 pF NOTE: 3770 tbl 04 1. This parameter is determined by device characterization, but is not production tested. PIN DESCRIPTIONS Name Description A0–A14 I/O0–I/O7 CS Addresses Data Input/Output Chip Select WE Write Enable OE GND Output Enable Ground VCC Power RECOMMENDED OPERATING TEMPERATURE AND SUPPLY VOLTAGE Grade Temperature GND VCC Commercial 0°C to +70°C 0V 3.3V ± 0.3V 3770 tbl 05 3770 tbl 01 RECOMMENDED DC OPERATING CONDITIONS TRUTH TABLE(1) WE CS OE I/O X H X High-Z Standby (ISB) X VHC X High-Z Standby (ISB1) H L H High-Z Output Disable H L L L L X DOUT DIN NOTE: 1. H = VIH, L = VIL, X = Don’t Care Function Symbol Read Write 3770 tbl 02 Parameter Min. Typ. Max. Unit VCC Supply Voltage 3.0 3.3 3.6 V GND Supply Voltage 0 0 0 V VIH Input High Voltage - Inputs 1.8 — 5.0 V VIH Input High Voltage - I/O 1.8 — Vcc+0.3 V VIL Input Low Voltage –0.5(1) — 0.8 V NOTE: 3770 tbl 06 1. VIL (min.) = –1.0V for pulse width less than 5ns, once per cycle. 2 IDT71V256SB 3.3V CMOS STATIC RAM WITH 2.5V COMPATIBLE INPUTS 256K (32K x 8-BIT) COMMERCIAL TEMPERATURE RANGE DC ELECTRICAL CHARACTERISTICS(1, 2) (VCC = 3.3V ± 0.3V, VLC = 0.2V, VHC = VCC - 0.2V) Symbol Parameter 71V256SB12 Com’l 71V256SB15 Com’l. 71V256SB20 Com’l. Unit ICC Dynamic Operating Current CS ≤ VIL, Outputs Open, VCC = Max., f = fMAX(2) 90 85 85 mA ISB Standby Power Supply Current (TTL Level) (2) CS = VIH, VCC = Max., Outputs Open, f = fMAX 20 20 20 mA ISB1 Full Standby Power Supply Current (CMOS Level) (2) CS ≥ VHC , VCC = Max., Outputs Open, f = 0 , VIN ≤ VLC or VIN ≥ VHC 2 2 2 mA NOTES: 1. All values are maximum guaranteed values. 2. fMAX = 1/tRC, only address inputs cycling at fmax; f = 0 means that no inputs are cycling. 3770 tbl 07 DC ELECTRICAL CHARACTERISTICS VCC = 3.3V± 0.3V IDT71V256SB Symbol Parameter Test Condition Min. Typ. Max. Unit |ILI| Input Leakage Current VCC = Max., VIN = GND to VCC — — 2 µA |ILO| VOL Output Leakage Current Output Low Voltage VCC = Max., CS = VIH, VOUT = GND to VCC IOL = 8mA, VCC = Min. — — — — 2 0.4 µA V VOH Output High Voltage IOH = –4mA, VCC = Min. 2.4 — — V 3770 tbl 08 AC TEST CONDITIONS Input Pulse Levels GND to 3.0V Input Rise/Fall Times Input Timing Reference Levels 3ns 1.5V Output Reference Levels 1.5V AC Test Load See Figures 1 and 2 3770 tbl 09 3.3V 3.3V 320Ω 320Ω DATA OUT DATA OUT 350Ω 350Ω 30pF* 3770 drw 04 5pF* 3770 drw 05 Figure 2. AC Test Load (for tCLZ, tOLZ, tCHZ, tOHZ, tOW, tWHZ) Figure 1. AC Test Load *Includes scope and jig capacitances 3 IDT71V256SB 3.3V CMOS STATIC RAM WITH 2.5V COMPATIBLE INPUTS 256K (32K x 8-BIT) COMMERCIAL TEMPERATURE RANGE AC ELECTRICAL CHARACTERISTICS (VCC = 3.3V ± 0.3V, Commercial Temperature Range) 71V256SA12 Symbol Parameter 71V256SA15 71V256SA20 Min. Max. Min. Max. Min. Max. Unit Read Cycle tRC Read Cycle Time tAA Address Access Time 12 — — 12 15 — — 15 20 — — 20 ns ns tACS 20 ns ns Chip Select Access Time — 12 — 15 — (1) Chip Select to Output in Low-Z 5 — 5 — 5 — tCHZ(1) Chip Select to Output in High-Z 0 8 0 9 0 10 ns tOE Output Enable to Output Valid — 6 — 7 — 8 ns tOLZ(1) tOHZ(1) Output Enable to Output in Low-Z Output Disable to Output in High-Z 3 2 — 6 0 0 — 7 0 0 — 8 ns ns tOH Output Hold from Address Change tCLZ 3 — 3 — 3 — ns Write Cycle tWC Write Cycle Time tAW Address Valid to End-of-Write tCW Chip Select to End-of-Write 12 9 9 — — — 15 10 10 — — — 20 15 15 — — — ns ns ns tAS Address Set-up Time 0 — 0 — 0 — ns tWP Write Pulse Width 9 — 10 — 15 — ns tWR Write Recovery Time 0 — 0 — 0 — ns tDW tDH tOW(1) tWHZ(1) Data to Write Time Overlap Data Hold from Write Time Output Active from End-of-Write Write Enable to Output in High-Z 6 0 4 1 — — — 8 7 0 4 1 — — — 9 8 0 4 1 — — — 10 ns ns ns ns NOTE: 1. This parameter guaranteed with the AC test load (Figure 2) by device characterization, but is not production tested. 3770 tbl 10 TIMING WAVEFORM OF READ CYCLE NO. 1(1) t RC ADDRESS t AA t OH OE t OE t OLZ (2) t OHZ (2) t CHZ (2) CS t ACS t CLZ DATAOUT (2) DATA VALID 3770 drw 06 NOTES: 1. WE is HIGH for Read cycle. 2. Transition is measured ±200mV from steady state. 4 IDT71V256SB 3.3V CMOS STATIC RAM WITH 2.5V COMPATIBLE INPUTS 256K (32K x 8-BIT) COMMERCIAL TEMPERATURE RANGE TIMING WAVEFORM OF READ CYCLE NO. 2(1, 2, 4) t RC ADDRESS t AA t OH DATAOUT t OH PREVIOUS DATA VALID DATA VALID 3770 drw 07 TIMING WAVEFORM OF READ CYCLE NO. 3(1, 3, 4) CS t ACS t CLZ t CHZ (5) (5) DATA VALID DATAOUT 3770 drw 08 NOTES: 1. WE is HIGH for Read cycle. 2. Device is continuously selected, CS is LOW. 3. Address valid prior to or coincident with CS transition LOW. 4. OE is LOW. 5. Transition is measured ±200mV from steady state. TIMING WAVEFORM OF WRITE CYCLE NO. 1 (WE CONTROLLED TIMING)(1, 2, 3, 5, 7) t WC ADDRESS t OHZ (6) OE t AW CS t WP t AS (7) t WR WE t WHZ DATAOUT (6) t OW (6) (4) (4) t DW DATAIN t DH DATA VALID 3770 drw 09 NOTES: 1. WE or CS must be HIGH during all address transitions. 2. A write occurs during the overlap of a LOW CS and a LOW WE. 3. tWR is measured from the earlier of CS or WE going HIGH to the end of the write cycle. 4. During this period, I/O pins are in the output state so that the input signals must not be applied. 5. If the CS LOW transition occurs simultaneously with or after the WE LOW transition, the outputs remain in a high-impedance state. 6. Transition is measured ±200mV from steady state. 7. If OE is LOW during a WE controlled write cycle, the write pulse width must be the larger of tWP or (tWHZ + tDW) to allow the I/O drivers to turn off and data to be placed on the bus for the required tDW. If OE is HIGH during a WE controlled write cycle, this requirement does not apply and the write pulse can be as short as the spectified tWP. 5 IDT71V256SB 3.3V CMOS STATIC RAM WITH 2.5V COMPATIBLE INPUTS 256K (32K x 8-BIT) COMMERCIAL TEMPERATURE RANGE TIMING WAVEFORM OF WRITE CYCLE NO. 2 (CS CONTROLLED TIMING)(1, 2, 3, 4) t WC ADDRESS t AW CS tAS t CW (5) tWR WE t DW t DH DATA VALID DATAIN 3770 drw 10 NOTES: 1. WE or CS must be HIGH during all address transitions. 2. A write occurs during the overlap of a LOW CS and a LOW WE. 3. tWR is measured from the earlier of CS or WE going HIGH to the end of the write cycle. 4. If the CS LOW transition occurs simultaneously with or after the WE LOW transition, the outputs remain in a high-impedance state. 5. If OE is LOW during a WE controlled write cycle, the write pulse width must be the larger of tWP or (tWHZ + tDW) to allow the I/O drivers to turn off and data to be placed on the bus for the required tDW. If OE is HIGH during a WE controlled write cycle, this requirement does not apply and the write pulse can be as short as the spectified tWP. ORDERING INFORMATION IDT 71V256 Device Type SB XX Y X Power/ Rev Speed Package Process/ Temperature Range Blank Commercial (0°C to +70°C) Y PZ 300 mil SOJ (SO28-5) TSOP Type I (SO28-8) 12 15 20 Speed in nanoseconds SB Standard Power, 2.5V Compatible Inputs 3770 drw 11 6