3.3 VOLT CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 FEATURES: • • • • • • • • • • • • • • • • • IDT72V201, IDT72V211 IDT72V221, IDT72V231 IDT72V241, IDT72V251 clocked read and write controls. The architecture, functional operation and pin assignments are identical to those of the IDT72201/72211/72221/72231/ 72241/72251, but operate at a power supply voltage (Vcc) between 3.0V and 3.6V. These devices have a 256, 512, 1,024, 2,048, 4,096 and 8,192 x 9-bit memory array, respectively. These FIFOs are applicable for a wide variety of data buffering needs such as graphics, local area networks and interprocessor communication. These FIFOs have 9-bit input and output ports. The input port is controlled by a free-running clock (WCLK), and two Write Enable pins (WEN1, WEN2). Data is written into the Synchronous FIFO on every rising clock edge when the Write Enable pins are asserted. The output port is controlled by another clock pin (RCLK) and two Read Enable pins (REN1, REN2). The Read Clock can be tied to the Write Clock for single clock operation or the two clocks can run asynchronous of one another for dualclock operation. An Output Enable pin (OE) is provided on the read port for three-state control of the output. The Synchronous FIFOs have two fixed flags, Empty (EF) and Full (FF). Two programmable flags, Almost-Empty (PAE) and Almost-Full (PAF), are provided for improved system control. The programmable flags default to Empty+7 and Full-7 for PAE and PAF, respectively. The programmable flag offset loading is controlled by a simple state machine and is initiated by asserting the Load pin (LD). These FIFOs are fabricated using IDT's high-speed submicron CMOS technology. 256 x 9-bit organization IDT72V201 512 x 9-bit organization IDT72V211 1,024 x 9-bit organization IDT72V221 2,048 x 9-bit organization IDT72V231 4,096 x 9-bit organization IDT72V241 8,192 x 9-bit organization IDT72V251 10 ns read/write cycle time 5V input tolerant Read and Write clocks can be independent Dual-Ported zero fall-through time architecture Empty and Full Flags signal FIFO status Programmable Almost-Empty and Almost-Full flags can be set to any depth Programmable Almost-Empty and Almost-Full flags default to Empty+7, and Full-7, respectively Output Enable puts output data bus in high-impedance state Advanced submicron CMOS technology Available in 32-pin plastic leaded chip carrier (PLCC) and 32-pin plastic Thin Quad FlatPack (TQFP) Industrial temperature range (–40°°C to +85°°C) is available DESCRIPTION: The IDT72V201/72V211/72V221/72V231/72V241/72V251 SyncFIFOs™ are very high-speed, low-power First-In, First-Out (FIFO) memories with FUNCTIONAL BLOCK DIAGRAM D0 - D8 WCLK WEN1 LD WEN2 INPUT REGISTER OFFSET REGISTER EF PAE PAF FF FLAG LOGIC WRITE CONTROL LOGIC RAM ARRAY 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9, 8,192 x 9 WRITE POINTER READ POINTER READ CONTROL LOGIC OUTPUT REGISTER RESET LOGIC RCLK REN1 REN2 RS OE 4092 drw 01 Q0 - Q8 IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc. SyncFIFO is a trademark of Integrated Device Technology, Inc. COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES FEBRUARY 2002 1 2002 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. DSC-4092/2 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 D1 1 24 WEN1 D0 2 23 WCLK PAF 3 22 WEN2/LD PAE 4 21 VCC GND 5 20 Q8 19 Q7 Q6 Q5 D8 D7 D6 D5 WEN1 PAF 7 27 WCLK PAE 8 26 WEN2/LD GND 9 25 VCC REN1 10 24 Q8 RCLK 11 23 Q7 REN2 12 22 Q6 OE 13 21 Q5 EF Q4 Q3 28 14 15 16 17 18 19 20 4092 drw02 Q2 Q1 Q0 FF OE EF 9 10 11 12 13 14 15 16 RS 6 TQFP (PR32-1, order code: PF) TOP VIEW Q4 REN2 17 29 D0 Q3 18 8 32 31 30 1 Q2 7 2 Q1 RCLK 3 5 Q0 6 4 D1 FF REN1 D4 32 31 30 29 28 27 26 25 D3 INDEX D2 RS D8 D7 D6 D5 D4 INDEX D3 D2 PIN CONFIGURATION 4092 drw02a PLCC (J32-1, order code: J) TOP VIEW PIN DESCRIPTIONS Symbol D0-D8 RS WCLK WEN1 WEN2/LD Q0-Q8 RCLK REN1 REN2 OE EF PAE PAF FF VCC GND Name Data Inputs Reset I/O Description I Data inputs for a 9-bit bus. I When RS is set LOW, internal read and write pointers are set to the first location of the RAM array, FF and PAF go HIGH, and PAE and EF go LOW. A Reset is required before an initial Write after power-up. Write Clock I Data is written into the FIFO on a LOW-to-HIGH transition of WCLK when the Write Enable(s) are asserted. Write Enable 1 I If the FIFO is configured to have programmable flags, WEN1 is the only Write Enable pin. When WEN1 is LOW, data is written into the FIFO on every LOW-to-HIGH transition WCLK. If the FIFO is configured to have two write enables, WEN1 must be LOW and WEN2 must be HIGH to write data into the FIFO. Data will not be written into the FIFO if the FF is LOW. Write Enable 2/ I The FIFO is configured at Reset to have either two write enables or programmable flags. If WEN2/ LD Load is HIGH at Reset, this pin operates as a second write enable. If WEN2/LD is LOW at Reset, this pin operates as a control to load and read the programmable flag offsets. If the FIFO is configured to have two write enables, WEN1 must be LOW and WEN2 must be HIGH to write data into the FIFO. Data will not be written into the FIFO if the FF is LOW. If the FIFO is configured to have programmable flags, WEN2/LD is held LOW to write or read the programmable flag offsets. Data Outputs O Data outputs for a 9-bit bus. Read Clock I Data is read from the FIFO on a LOW-to-HIGH transition of RCLK when REN1 and REN2 are asserted. Read Enable 1 I When REN1 and REN2 are LOW, data is read from the FIFO on every LOW-to-HIGH transition of RCLK. Data will not be read from the FIFO if the EF is LOW. Read Enable 2 I When REN1 and REN2 are LOW, data is read from the FIFO on every LOW-to-HIGH transition of RCLK. Data will not be read from the FIFO if the EF is LOW. Output Enable I When OE is LOW, the data output bus is active. If OE is HIGH, the output data bus will be in a high-impedance state. Empty Flag O When EF is LOW, the FIFO is empty and further data reads from the output are inhibited. When EF is HIGH, the FIFO is not empty. EF is synchronized to RCLK. Programmable O When PAE is LOW, the FIFO is almost-empty based on the offset programmed into the FIFO. The default Almost-Empty Flag offset at reset is Empty+7. PAE is synchronized to RCLK. Programmable O When PAF is LOW, the FIFO is almost-full based on the offset programmed into the FIFO. The default Almost-Full Flag offset at reset is Full-7. PAF is synchronized to WCLK. Full Flag O When FF is LOW, the FIFO is full and further data writes into the input are inhibited. When FF is HIGH, the FIFO is not full. FF is synchronized to WCLK. Power One 3.3V volt power supply pin. Ground One 0 volt ground pin. 2 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 RECOMMENDED OPERATING CONDITIONS ABSOLUTE MAXIMUM RATINGS(1) Symbol VTERM(2) Rating Terminal Voltage with Respect to GND Com'l & Ind'l –0.5 to +5 Unit V TSTG Storage Temperature –55 to +125 °C IOUT DC Output Current –50 to +50 mA Symbol VCC GND VIH NOTE: 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 the specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability. 2. VCC terminal only. VIL Parameter Supply Voltage Commercial/Industrial Supply Voltage Input High Voltage Commercial/Industrial Input Low Voltage Commercial/Industrial Min. 3.0 Typ. 3.3 Max. 3.6 Unit V 0 2.0 0 — 0 5.5 V V -0.5 — 0.8 V TA Operating Temperature Commercial 0 — 70 °C TA Operating Temperature Industrial -40 — 85 °C DC ELECTRICAL CHARACTERISTICS (Commercial: VCC = 3.3V ± 0.3V, TA = 0°C to +70°C;Industrial: VCC = 3.3V ± 0.3V, TA = -40°C to +85°C) Symbol Parameter Min. IDT72V201 IDT72V211 IDT72V221 IDT72V231 IDT72V241 IDT72V251 Commercial and Industrial(1) tCLK = 10, 15, 20 ns Typ. Max. Unit ILI Input Leakage Current (Any Input) –1 — 1 µA ILO(3) Output Leakage Current –10 — 10 µA VOH Output Logic “1” Voltage, IOH = –2mA 2.4 — — V VOL Output Logic “0” Voltage, IOL = 8mA — — 0.4 V Active Power Supply Current — — 20 mA Standby Current — — 5 mA (2) ICC1(4,5,6) (4,7) ICC2 NOTES: 1. Industrial temperature range product for the 15ns speed grade is available as a standard device. All other speed grades are available by special order. 2. Measurements with 0.4 ≤ VIN ≤ VCC. 3. OE ≥ VIH, 0.4 ≤ VOUT ≤ VCC. 4. Tested with outputs disabled (IOUT = 0). 5. RCLK and WCLK toggle at 20 MHz and data inputs switch at 10 MHz. 6. Typical ICC1 = 0.17 + 0.48*fS + 0.02*CL*fS (in mA) with VCC = 3.3V, TA = 25°C, fS = WCLK frequency = RCLK frequency (in MHz, using TTL levels), data switching at fS/2, CL = capacitive load (in pF). 7. All Inputs = VCC - 0.2V or GND + 0.2V, except RCLK and WCLK, which toggle at 20 MHz. CAPACITANCE (TA = +25°C, f = 1.0MHz) Symbol CIN(2) Parameter Input Capacitance Conditions VIN = 0V Max. 10 Unit pF COUT(1,2) Output Capacitance VOUT = 0V 10 pF NOTES: 1. With output deselected (OE ≥ VIH). 2. Characterized values, not currently tested. 3 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 AC ELECTRICAL CHARACTERISTICS(1) (Commercial: VCC = 3.3 ±0.3V, TA = 0°C to + 70°C;Industrial: VCC = 3.3 ±0.3V, TA = -40°C to + 85°C) Symbol fS Commercial IDT72V201L10 IDT72V211L10 IDT72V221L10 IDT72V231L10 IDT72V241L10 IDT72V251L10 Min. Max. — 100 Parameter Clock Cycle Frequency Com'l & Ind'l(2) IDT72V201L15 IDT72V211L15 IDT72V221L15 IDT72V231L15 IDT72V241L15 IDT72V251L15 Min. Max. — 66.7 Commercial IDT72V201L20 IDT72V211L20 IDT72V221L20 IDT72V231L20 IDT72V241L20 IDT72V251L20 Min. Max. — 50 Unit MHz tA Data Access Time 2 6.5 2 10 2 12 ns tCLK Clock Cycle Time 10 — 15 — 20 — ns tCLKH Clock High Time 4.5 — 6 — 8 — ns tCLKL Clock Low Time 4.5 — 6 — 8 — ns tDS Data Setup Time 3 — 4 — 5 — ns tDH Data Hold Time 0.5 — 1 — 1 — ns tENS Enable Setup Time 3 — 4 — 5 — ns tENH Enable Hold Time 0.5 — 1 — 1 — ns tRS Reset Pulse Width(1) 10 — 15 — 20 — ns tRSS Reset Setup Time 8 — 10 — 12 — ns tRSR Reset Recovery Time 8 — 10 — 12 — ns tRSF Reset to Flag and Output Time — 10 — 15 — 20 ns tOLZ Output Enable to Output in Low-Z(3) 0 — 0 — 0 — ns tOE Output Enable to Output Valid 3 — 3 8 3 10 ns tOHZ Output Enable to Output in High-Z(3) 3 — 3 8 3 10 ns tWFF Write Clock to Full Flag — 6.5 — 10 — 12 ns tREF Read Clock to Empty Flag — 6.5 — 10 — 12 ns tAF Write Clock to Almost-Full Flag — 6.5 — 10 — 12 ns tAE Read Clock to Almost-Empty Flag — 6.5 — 10 — 12 ns tSKEW1 Skew time between Read Clock & Write Clock for Empty Flag &Full Flag 5 — 6 — 8 — ns tSKEW2 Skew time between Read Clock & Write Clock for Almost-Empty Flag & Almost-Full Flag 14 — 18 — 20 — ns NOTES: 1. Pulse widths less than minimum values are not allowed. 2. Industrial temperature range is available by special order for speed grades faster than 15ns. 3. Values guaranteed by design, not currently tested. 3.3V 330Ω D.U.T. AC TEST CONDITIONS In Pulse Levels Input Rise/Fall Times 30pF* 3ns Input Timing Reference Levels 1.5V Output Reference Levels 1.5V Output Load 510Ω GND to 3.0V 4092 drw03 or equivalent circuit See Figure 1 Figure 1. Output Load *Includes jig and scope capacitances. 4 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 SIGNAL DESCRIPTIONS OUTPUT ENABLE (OE) When Output Enable (OE) is enabled (LOW), the parallel output buffers receive data from the output register. When Output Enable (OE) is disabled (HIGH), the Q output data bus is in a high-impedance state. INPUTS: DATA IN (D0 - D8) Data inputs for 9-bit wide data. WRITE ENABLE 2/LOAD (WEN2/LD) This is a dual-purpose pin. The FIFO is configured at Reset to have programmable flags or to have two write enables, which allows depth expansion. If Write Enable 2/Load (WEN2/LD) is set high at Reset (RS = LOW), this pin operates as a second Write Enable pin. If the FIFO is configured to have two write enables, when Write Enable (WEN1) is LOW and Write Enable 2/Load (WEN2/LD) is HIGH, data can be loaded into the input register and RAM array on the LOW-to-HIGH transition of every Write Clock (WCLK). Data is stored in the RAM array sequentially and independently of any on-going read operation. In this configuration, when Write Enable (WEN1) is HIGH and/or Write Enable 2/Load (WEN2/LD) is LOW, the input register holds the previous data and no new data is allowed to be loaded into the register. To prevent data overflow, the Full Flag (FF) will go LOW, inhibiting further write operations. Upon the completion of a valid read cycle, the Full Flag (FF) will go HIGH after tWFF, allowing a valid write to begin. Write Enable 1 (WEN1) and Write Enable 2/Load (WEN2/LD) are ignored when the FIFO is full. The FIFO is configured to have programmable flags when the Write Enable 2/Load (WEN2/LD) is set LOW at Reset (RS = LOW). The IDT72V201/72V211/ 72V221/72V231/72V241/72V251 devices contain four 8-bit offset registers which can be loaded with data on the inputs, or read on the outputs. See Figure 3 for details of the size of the registers and the default values. If the FIFO is configured to have programmable flags when the Write Enable 1 (WEN1) and Write Enable 2/Load (WEN2/LD) are set low, data on the inputs D is written into the Empty (Least Significant Bit) Offset register on the first LOWto-HIGH transition of the Write Clock (WCLK). Data is written into the Empty (Most Significant Bit) Offset register on the second LOW-to-HIGH transition of the Write Clock (WCLK), into the Full (Least Significant Bit) Offset register on the third transition, and into the Full (Most Significant Bit) Offset register on the fourth transition. The fifth transition of the Write Clock (WCLK) again writes to the Empty (Least Significant Bit) Offset register. However, writing all offset registers does not have to occur at one time. One or two offset registers can be written and then by bringing the Write Enable 2/ Load (WEN2/LD) pin HIGH, the FIFO is returned to normal read/write operation. When the Write Enable 2/Load (WEN2/LD) pin is set LOW, and Write Enable 1 (WEN1) is LOW, the next offset register in sequence is written. The contents of the offset registers can be read on the output lines when the Write Enable 2/Load (WEN2/LD) pin is set low and both Read Enables (REN1, REN2) are set LOW. Data can be read on the LOW-to-HIGH transition of the Read Clock (RCLK). A read and write should not be performed simultaneously to the offset registers. CONTROLS: RESET (RS) Reset is accomplished whenever the Reset (RS) input is taken to a LOW state. During reset, both internal read and write pointers are set to the first location. A reset is required after power-up before a write operation can take place. The Full Flag (FF) and Programmable Almost-Full Flag (PAF) will be reset to HIGH after tRSF. The Empty Flag (EF) and Programmable Almost-Empty Flag (PAE) will be reset to LOW after tRSF. During reset, the output register is initialized to all zeros and the offset registers are initialized to their default values. WRITE CLOCK (WCLK) A write cycle is initiated on the LOW-to-HIGH transition of the Write Clock (WCLK). Data setup and hold times must be met in respect to the LOW-to-HIGH transition of the Write Clock (WCLK). The Full Flag (FF) and Programmable Almost-Full Flag (PAF) are synchronized with respect to the LOW-to-HIGH transition of the Write Clock (WCLK). The Write and Read clocks can be asynchronous or coincident. WRITE ENABLE 1 (WEN1) If the FIFO is configured for programmable flags, Write Enable 1 (WEN1) is the only enable control pin. In this configuration, when Write Enable 1 (WEN1) is low, data can be loaded into the input register and RAM array on the LOWto-HIGH transition of every Write Clock (WCLK). Data is stored in the RAM array sequentially and independently of any on-going read operation. In this configuration, when Write Enable 1 (WEN1) is HIGH, the input register holds the previous data and no new data is allowed to be loaded into the register. If the FIFO is configured to have two write enables, which allows for depth expansion, there are two enable control pins. See Write Enable 2 paragraph below for operation in this configuration. To prevent data overflow, the Full Flag (FF) will go LOW, inhibiting further write operations. Upon the completion of a valid read cycle, the Full Flag (FF) will go HIGH after tWFF, allowing a valid write to begin. Write Enable 1 (WEN1) is ignored when the FIFO is full. READ CLOCK (RCLK) Data can be read on the outputs on the LOW-to-HIGH transition of the Read Clock (RCLK). The Empty Flag (EF) and Programmable Almost-Empty Flag (PAE) are synchronized with respect to the LOW-to-HIGH transition of the Read Clock (RCLK). The Write and Read clocks can be asynchronous or coincident. READ ENABLES (REN1, REN2) When both Read Enables (REN1, REN2) are LOW, data is read from the RAM array to the output register on the LOW-to-HIGH transition of the Read Clock (RCLK). When either Read Enable (REN1, REN2) is HIGH, the output register holds the previous data and no new data is allowed to be loaded into the register. When all the data has been read from the FIFO, the Empty Flag (EF) will go LOW, inhibiting further read operations. Once a valid write operation has been accomplished, the Empty Flag (EF) will go HIGH after tREF and a valid read can begin. The Read Enables (REN1, REN2) are ignored when the FIFO is empty. LD WEN1 0 0 Empty Offset (LSB) Empty Offset (MSB) Full Offset (LSB) Full Offset (MSB) 0 1 No Operation 1 0 Write Into FIFO 1 1 No Operation WCLK Selection NOTES: 1. For the purposes of this table, WEN2 = VIH. 2. The same selection sequence applies to reading from the registers. REN1 and REN2 are enabled and read is performed on the LOW-to-HIGH transition of RCLK. Figure 2. Write Offset Register 5 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 IDT72V201 - 256 x 9-BIT 8 7 IDT72V221 - 1,024 x 9-BIT IDT72V211 - 512 x 9-BIT 0 8 0 7 8 7 0 Empty Offset (LSB) Reg. Empty Offset (LSB) Empty Offset (LSB) Reg. Default Value 007H Default Value 007H Default Value 007H 8 0 8 0 1 8 0 1 (MSB) (MSB) 00 0 8 7 0 8 0 7 0 8 7 8 8 8 0 1 8 (MSB) 0 00 IDT72V251 - 8,192 x 9-BIT 0 7 8 0 7 Empty Offset (LSB) Empty Offset (LSB) Default Value 007H Default Value 007H Default Value 007H 0 2 8 0 1 (MSB) Empty Offset (LSB) Reg. 0 3 8 0 4 (MSB) (MSB) (MSB) 000 0000 00000 7 0 8 Full Offset (LSB) Reg. Default Value 007H 8 Default Value 007H IDT72V241 - 4,096 x 9-BIT 0 0 Full Offset (LSB) Reg. Default Value 007H IDT72V231 - 2,049 x 9-BIT 8 7 Full Offset (LSB) Full Offset (LSB) Reg. Default Value 007H 8 8 0 2 0 7 8 0 7 Full Offset (LSB) Full Offset (LSB) Default Value 007H Default Value 007H 8 0 3 8 0 4 (MSB) (MSB) (MSB) 000 0000 00000 4092 drw 05 Figure 3. Offset Register Location and Default Values 6 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 OUTPUTS: IDT72V221, (2,048-m) writes for the IDT72V231, (4,096-m) writes for the IDT72V241 and (8,192-m) writes for the IDT72V251. The offset “m” is defined in the Full Offset registers. If there is no full offset specified, the Programmable Almost-Full flag (PAF) will go LOW at Full-7 words. The Programmable Almost-Full flag (PAF) is synchronized with respect to the LOW-to-HIGH transition of the Write Clock (WCLK). FULL FLAG (FF) The Full Flag (FF) will go LOW, inhibiting further write operation, when the device is full. If no reads are performed after Reset (RS), the Full Flag (FF) will go LOW after 256 writes for the IDT72V201, 512 writes for the IDT72V211, 1,024 writes for the IDT72V221, 2,048 writes for the IDT72V231, 4,096 writes for the IDT72V241 and 8,192 writes for the IDT72V251. The Full Flag (FF) is synchronized with respect to the LOW-to-HIGH transition of the Write Clock (WCLK). PROGRAMMABLE ALMOST-EMPTY FLAG (PAE) The Programmable Almost-Empty flag (PAE) will go LOW when the read pointer is "n+1" locations less than the write pointer. The offset "n" is defined in the Empty Offset registers. If no reads are performed after Reset the Programmable Almost-Empty flag (PAE) will go HIGH after "n+1" for the IDT72V201/72V211/72V221/72V231/72V241/72V251. If there is no empty offset specified, the Programmable Almost-Empty flag (PAE) will go LOW at Empty+7 words. The Programmable Almost-Empty flag (PAE) is synchronized with respect to the LOW-to-HIGH transition of the Read Clock (RCLK). EMPTY FLAG (EF) The Empty Flag (EF) will go LOW, inhibiting further read operations, when the read pointer is equal to the write pointer, indicating the device is empty. The Empty Flag (EF) is synchronized with respect to the LOW-to-HIGH transition of the Read Clock (RCLK). PROGRAMMABLE ALMOST-FULL FLAG (PAF) The Programmable Almost-Full flag (PAF) will go LOW when the FIFO reaches the almost-full condition. If no reads are performed after Reset (RS), the Programmable Almost-Full flag (PAF) will go LOW after (256-m) writes for the IDT72V201, (512-m) writes for the IDT72V211, (1,024-m) writes for the DATA OUTPUTS (Q0 - Q8) Data outputs for a 9-bit wide data. TABLE 1 STATUS FLAGS NUMBER OF WORDS IN FIFO IDT72V201 IDT72V211 IDT72V221 FF PAF PAE EF 0 1 to n(1) (n+1) to (256-(m+1)) 0 1 to n(1) (n+1) to (512-(m+1)) 0 1 to n(1) (n+1) to (1,024-(m+1)) H H H H H H L L H L H H (256-m)(2) to 255 (512-m)(2) to 511 (1,024-m)(2) to 1,023 H L H H 256 512 1,024 L L H H NUMBER OF WORDS IN FIFO IDT72V231 IDT72V241 IDT72V251 FF PAF PAE EF 0 0 0 H H L L H H L H (1) 1 to n (1) (1) 1 to n 1 to n (n+1) to (2,048-(m+1)) (n+1) to (4,096-(m+1)) (n+1) to (8,192-(m+1)) H H H H (2,048-m)(2) to 2,047 (4,096-m)(2) to 4,095 (8,192-m)(2) to 8,191 H L H H 2,048 4,096 8,192 L L H H NOTES: 1. n = Empty Offset (n = 7 default value) 2. m = Full Offset (m = 7 default value) 7 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 tRS RS tRSS tRSR tRSS tRSR tRSS tRSR REN1, REN2 WEN1 WEN2/LD (1) tRSF EF, PAE tRSF FF, PAF tRSF OE = 1 (2) Q0 - Q8 OE = 0 4092 drw06 NOTES: 1. Holding WEN2/LD HIGH during reset will make the pin act as a second write enable pin. Holding WEN2/LD LOW during reset will make the pin act as a load enable for the programmable flag offset registers. 2. After reset, the outputs will be LOW if OE = 0 and high-impedance if OE = 1. 3. The clocks (RCLK, WCLK) can be free-running during reset. Figure 4. Reset Timing tCLK tCLKH tCLKL WCLK tDS tDH D0 - D8 DATA IN VALID tENH tENS NO OPERATION WEN1 tENS tENH WEN2/ (If Applicable) NO OPERATION tWFF tWFF FF tSKEW1(1) RCLK REN1, REN2 4092 drw07 NOTE: 1. tSKEW1 is the minimum time between a rising RCLK edge and a rising WCLK edge for FF to change during the current clock cycle. If the time between the rising edge of RCLK and the rising edge of WCLK is less than tSKEW1, then FF may not change state until the next WCLK edge. Figure 5. Write Cycle Timing 8 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 tCLK tCLKL tCLKH RCLK tENS tENH REN1, REN2 NO OPERATION tREF tREF EF tA VALID DATA Q0 - Q8 tOLZ tOHZ tOE OE tSKEW1 (1) WCLK WEN1 WEN2 4092 drw08 NOTE: 1. tSKEW1 is the minimum time between a rising WCLK edge and a rising RCLK edge for EF to change during the current clock cycle. If the time between the rising edge of RCLK and the rising edge of WCLK is less than tSKEW1, then EF may not change state until the next RCLK edge. Figure 6. Read Cycle Timing WCLK tDS D1 D0 - D8 D2 D3 D0 (First Valid Write) tENS WEN1 tENS WEN2 (If Applicable) (1) tFRL tSKEW1 RCLK tREF EF tENS REN1, REN2 tA tA D0 Q0 - Q8 tOLZ D1 tOE OE NOTE: 1. When tSKEW1 ≥ minimum specification, tFRL = tCLK + tSKEW1 When tSKEW1 < minimum specification, tFRL = 2tCLK + tSKEW1 or tCLK + tSKEW1 The Latency Timings apply only at the Empty Boundary (EF = LOW). 4092 drw09 Figure 7. First Data Word Latency Timing 9 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 NO WRITE NO WRITE NO WRITE WCLK tSKEW1 tSKEW1 tDS D0 - D8 tWFF tWFF tWFF FF (1) tENS tENH tENS tENS tENH tENS WEN1 (1) WEN2 (If Applicable) RCLK tENS REN1, REN2 tENH tENS tENH tA OE LOW tA Q0 - Q8 DATA READ DATA IN OUTPUT REGISTER NEXT DATA READ 4092 drw10 NOTE: 1. Only one of the two Write Enable inputs, WEN1 or WEN2, needs to go inactive to inhibit writes to the FIFO. Figure 8. Full Flag Timing WCLK tDS tDS DATA WRITE 1 D0 - D8 DATA WRITE 2 tENS tENH tENS tENH tENS tENH tENS tENH WEN1 WEN2 (If Applicable) (1) tSKEW1 (1) tFRL tSKEW1 tFFL RCLK tREF tREF tREF EF REN1, REN2 OE LOW tA Q0 - Q8 DATA READ DATA IN OUTPUT REGISTER 4092 drw11 NOTE: 1. When tSKEW1 ≥ minimum specification, tFRL maximum = tCLK + tSKEW1 When tSKEW1 < minimum specification, tFRL maximum = 2tCLK + tSKEW1 or tCLK + tSKEW1 The Latency Timings apply only at the Empty Boundary (EF = LOW). Figure 9. Empty Flag Timing 10 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 tCLKH tCLKL (4) WCLK tENS tENH tENS tENH WEN1 WEN2 (If Applicable) tPAF Full - (m + 1) words in FIFO PAF (1) Full - m words in FIFO tSKEW2 (2) (3) tPAF RCLK tENS tENH REN1, REN2 4092 drw12 NOTES: 1. m = PAF offset. 2. 256 - m words in FIFO for IDT72V201, 512 - m words for IDT72V211, 1,024 - m words for IDT72V221, 2,048 - m words for IDT72V231, 4,096 - m words for IDT72V241, 8,192 - m words for IDT72V251. 3. tSKEW2 is the minimum time between a rising RCLK edge and a rising WCLK edge for PAF to change during that clock cycle. If the time between the rising edge of RCLK and the rising edge of WCLK is less than tSKEW2, then PAF may not change state until the next WCLK rising edge. 4. If a write is performed on this rising edge of the write clock, there will be Full - (m-1) words in the FIFO when PAF goes LOW. Figure 10. Programmable Full Flag Timing tCLKH tCLKL WCLK tENS tENH tENS tENH WEN1 WEN2 (If Applicable) PAE n + 1 words in FIFO n words in FIFO (1) tSKEW2 (2) tPAE tPAE (3) RCLK tENS REN1, REN2 tENH 4092 drw13 NOTES: 1. n = PAE offset. 2. tSKEW2 is the minimum time between a rising WCLK edge and a rising RCLK edge for PAE to change during that clock cycle. If the time between the rising edge of WCLK and the rising edge of RCLK is less than tSKEW2, then PAE may not change state until the next RCLK rising edge. 3. If a read is performed on this rising edge of the read clock, there will be Empty + (n-1) words in the FIFO when PAE goes LOW. Figure 11. Programmable Empty Flag Timing 11 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 tCLK tCLKH tCLKL WCLK tENS tENH LD tENS WEN1 tDS tDH D0 - D7 PAE OFFSET (LSB) PAE OFFSET (MSB) PAF OFFSET (LSB) PAF OFFSET (MSB) 4092 drw14 Figure 12. Write Offset Registers Timing tCLK tCLKH tCLKL RCLK tENS tENH LD tENS REN1, REN2 tA Q0 - Q7 DATA IN OUTPUT REGISTER EMPTY OFFSET (LSB) EMPTY OFFSET (MSB) FULL OFFSET (LSB) FULL OFFSET (MSB) 4092 drw15 Figure 13. Read Offset Registers Timing 12 COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES IDT72V201/72V211/72V221/72V231/72V241/72V251 3.3V CMOS SyncFIFO™ 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 OPERATING CONFIGURATIONS the Read Enable 2 (REN2) control input can be grounded (see Figure 14). In this configuration, the Write Enable 2/Load (WEN2/LD) pin is set LOW at Reset so that the pin operates as a control to load and read the programmable flag offsets. SINGLE DEVICE CONFIGURATION A single IDT72V201/72V211/72V221/72V231/72V241/72V251 may be used when the application requirements are for 256/512/1,024/2,048/4,096/ 8,192 words or less. When these FIFOs are in a Single Device Configuration, RESET (RS) WRITE CLOCK (WCLK) WRITE ENABLE 1 (WEN1) WRITE ENABLE 2/LOAD (WEN2/LD) DATA IN (D0 - D8) FULL FLAG (FF) PROGRAMMABLE ALMOST-FULL (PAF) READ CLOCK (RCLK) IDT 72V201 72V211 72V221 72V231 72V241 72V251 READ ENABLE 1 (REN1) OUTPUT ENABLE (OE) DATA OUT (Q0 - Q8) EMPTY FLAG (EF) PROGRAMMABLE ALMOST-EMPTY ( PAE) 4092 drw16 READ ENABLE 2 (REN2) Figure 14. Block Diagram of Single 256 x 9, 512 x 9, 1,024 x 9, 2,048 x 9, 4,096 x 9 and 8,192 x 9 Synchronous FIFO WIDTH EXPANSION CONFIGURATION Word width may be increased simply by connecting the corresponding input controls signals of multiple devices. A composite flag should be created for each of the end-point status flags (EF and FF). The partial status flags (AE and AF) can be detected from any one device. Figure 15 demonstrates a 18-bit word width by using two IDT72V201/72V211/72V221/72V231/72V241/72V251s. Any word width can be attained by adding additional IDT72V201/72V211/ 72V221/72V231/72V241/72V251s. When these devices are in a Width Expansion Configuration, the Read Enable 2 (REN2) control input can be grounded (see Figure 15). In this configuration, the Write Enable 2/Load (WEN2/LD) pin is set LOW at Reset so that the pin operates as a control to load and read the programmable flag offsets. 1,024/2,048/4,096/8,192 words. The existence of two enable pins on the read and write port allow depth expansion. The Write Enable 2/Load pin is used as a second write enable in a depth expansion configuration thus the programmable flags are set to the default values. Depth expansion is possible by using one enable input for system control while the other enable input is controlled by expansion logic to direct the flow of data. A typical application would have the expansion logic alternate data access from one device to the next in a sequential manner. These FIFOs operate in the Depth Expansion configuration when the following conditions are met: 1. The WEN2/ LD pin is held HIGH during Reset so that this pin operates a second Write Enable. 2. External logic is used to control the flow of data. Please see the Application Note" DEPTH EXPANSION OF IDT'S SYNCHRONOUS FIFOs USING THE RING COUNTER APPROACH" for details of this configuration. DEPTH EXPANSION The IDT72V201/72V211/72V221/72V231/72V241/72V251 can be adapted to applications when the requirements are for greater than 256/512/ RESET (RS) DATA IN (D) 18 RESET (RS) 9 9 READ CLOCK (RCLK) WRITE CLOCK (WCLK) READ ENABLE (REN) WRITE ENABLE1 (WEN1) WRITE ENABLE2/LOAD (WEN2/LD) FULL FLAG (FF) #1 FULL FLAG (FF) #2 PROGRAMMABLE (PAF) IDT 72V201 72V211 72V221 72V231 72V241 72V251 IDT 72V201 72V211 72V221 72V231 72V241 72V251 9 READ ENABLE 2 (REN2) OUTPUT ENABLE (OE) PROGRAMMABLE (PAE) EMPTY FLAG (EF) #1 EMPTY FLAG (EF) #2 9 DATA OUT (Q) READ ENABLE 2 (REN2) Figure 15. Block Diagram of 256 x 18, 512 x 18, 1,024 x 18, 2,048 x 18, 4,096 x 18 and 8,192 x 18 Synchronous FIFO Used in a Width Expansion Configuration 13 18 4092 drw17 ORDERING INFORMATION IDT XXXXX Device Type X Power XX Speed X Package X Process/ Temperature Range BLANK I(1) Commercial (0°C to +70°C) Industrial (-40°C to +85°C) J PF Plastic Leaded Chip Carrier (PLCC, J32-1) Plastic Thin Quad Flatpack (TQFP, PR32-1) 10 15 20 Commercial Only Commercial & Industrial Clock Cycle Time (tCLK) Speed in Nanoseconds Commercial Only L Low Power 72V201 72V211 72V221 72V231 72V241 72V251 256 x 9 512 x 9 1,024 x 9 2,048 x 9 4,096 x 9 8,192 x 9 3.3V SyncFIFO 3.3V SyncFIFO 3.3V SyncFIFO 3.3V SyncFIFO 3.3V SyncFIFO 3.3V SyncFIFO 4092 drw 18 NOTE: 1. Industrial temperature range product for the 15ns is available as a standard device. All other speed grades are available by special order. DATASHEET DOCUMENT HISTORY 01/11/2002 02/01/2002 pg. 3. pg. 3. 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