L8C204JC15

L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO DESCRIPTION The L8C201, L8C202, L8C203, and L8C204 are dual-port First-In/FirstOut (FIFO) memories. The FIFO memory products are organized as: L8C201 — 512 x 9-bit L8C202 — 1024 x 9-bit L8C203 — 2048 x 9-bit L8C204 — 4096 x 9-bit Each device utilizes a special algorithm that loads and empties data on a firstin/first-out basis. Full and Empty flags are provided to prevent data overflow and underflow. Three additional pins are also provided to allow for unlimited expansion in both word size and depth. Depth Expansion does not result in a flow-through penalty. Multiple devices are connected with the data and control signals in parallel. The active device is determined by the Expansion In (XI) and Expansion Out (XO) signals which are daisy chained from device to device. The read and write operations are internally sequential through the use of ring pointers. No address information is required to load and unload data. The write operation occurs when the Write (W) signal is LOW. Read occurs when Read (R) goes LOW. The nine data outputs go to the high impedance state when R is HIGH. Retransmit (RT) capability allows for reset of the read pointer when RT is pulsed LOW, allowing for retransmission of data from the beginning. Read Enable (R) and Write Enable (W) must both be HIGH during a retransmit cycle, and then R is used to access the data. A Half-Full (HF) output flag is available in the single device and width expansion modes. In the depth expansion configuration, this pin provides the Expansion Out (XO) information which is used to tell the next FIFO that it will be activated. These FIFOs are designed to have the fastest data access possible. Even in lower cycle time applications, faster access time can eliminate timing bottlenecks as well as leave enough margin to allow the use of the devices without external bus drivers. READ POINTER FEATURES u First-In/First-Out (FIFO) using Dual-Port Memory u Advanced CMOS Technology u High Speed — to 10 ns Access Time u Asynchronous and Simultaneous Read and Write u Fully Expandable by both Word Depth and/or Bit Width u u u u Empty and Full Warning Flags Half-Full Flag Capability Auto Retransmit Capability Package Styles Available: • 28-pin Plastic DIP • 32-pin Plastic LCC • 28-pin Ceramic Flatpack L8C201/202/203/204 BLOCK DIAGRAM DATA INPUTS D8-0 9 W WRITE CONTROL RAM ARRAY 512 x 9-bit 1K x 9-bit 2K x 9-bit 4K x 9-bit WRITE POINTER The FIFOs are designed for those applications requiring asychronous and simultaneous read/writes in multiprocessing and rate buffer applications. THREE-STATE BUFFERS R READ CONTROL DATA OUTPUTS Q8-0 RS FL/RT RESET LOGIC FLAG LOGIC EF FF XI EXPANSION LOGIC XO/HF FIFO Products 1 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO “final” read cycle but inhibiting further read operations with the data outputs remaining in a high impedance state. Once a valid write operating has been accomplished, the Empty Flag (EF) will go HIGH after tWHEH and a valid read can then begin. When the FIFO is empty, the internal read pointer is blocked from R so external changes in R will not affect the FIFO. FL/RT — First Load/Retransmit Outputs FF — Full Flag The Full Flag (FF) will go LOW, inhibiting further write operations, indicating that the device is full. If the read pointer is not moved after Reset (RS), the Full Flag (FF) will go LOW after 512 writes for the L8C201, 1024 writes for the L8C202, 2048 writes for the L8C203, and 4096 writes for the L8C204. EF — Empty Flag SIGNAL DEFINITIONS Inputs RS — Reset 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. Both the Read Enable (R) and Write Enable (W) inputs must be in the HIGH state during the window shown (i.e., tWHSH before the rising edge of RS) and should not change until tSHWL after the rising edge of RS. Hall-Full Flag (HF) will be reset to high after Reset (RS). W — Write Enable A write cycle is initiated on the falling edge of this input if the Full Flag (FF) is not set. Data setup and hold time must be adhered to with respect to the rising edge of the Write Enable (W). Data is stored in the RAM array sequentially and independently of any on-going read operation. To prevent data overflow, the Full Flag (FF) will go LOW, inhibiting further write operations. Upon the completion of a valid read operation, the Full Flag (FF) will go HIGH after tRHFH, allowing a valid write to begin. When the FIFO is full, the internal write pointer is blocked from W, so external changes in W will not affect the FIFO when it is full. R — Read Enable This is a dual-purpose input. In the Depth Expansion Mode, this pin is grounded to indicate that it is the first loaded (see Operating Modes). In the Single Device Mode, this pin acts as the retransmit input. The Single Device Mode is initiated by grounding the Expansion In (XI). The FIFOs can be made to retransmit data when the Retransmit Enable control (RT) input is pulsed LOW. A retransmit operation will set the internal read pointer to the first location and will not affect the write pointer. Read Enable (R) and Write Enable (W) must be in the HIGH state during retransmit. This feature is useful when less than the full memory has been written between resets. Retransmit will affect the Half-Full Flag (HF), depending on the relative locations of the read and write pointers. The retransmit feature is not compatible with the Depth Expansion Mode. XI — Expansion In This input is a dual-purpose pin. Expansion In (XI) is grounded to indicate an operation in the single device mode. Expansion In (XI) is connected to Expansion Out (XO) of the previous device in the Depth Expansion or Daisy Chain Mode. D8-0 — Data Input Data input signals for 9-bit wide data. Data has setup and hold time requirements with respect to the rising edge of W. BS O 2 A read cycle is initiated on the falling edge of the Read Enable (R) provided the Empty Flag (EF) is not set. The data is accessed on a First-In/FirstOut basis, independent of any ongoing write operation. After Read Enable (R) goes HIGH, the Data Outputs (D8-0) will return to a high impedance condition until the next read operation. When all the data has been read from the FIFO, the Empty Flag (EF) will go LOW, allowing the O LE TE Q8-0 — Data Output The Empty Flag (EF) will go LOW, inhibiting further read operations, when the read pointer is equal to the write pointer, indicating that the device is empty. XO/HF — Expansion Out/Half-Full Flag This is a dual-purpose output. In the Single Device Mode, when Expansion In (XI) is grounded, this output acts as an indication of a half-full memory. After half of the memory is filled and at the falling edge of the next write operation, the Half-Full Flag (HF) will be set to LOW and will remain set until the difference between the write pointer and read pointer is less than or equal to one-half of the total memory of the device. The Half-Full Flag (HF) is then deasserted by the rising edge of the read operation. In the Depth Expansion Mode, Expansion In (XI) is connected to Expansion Out (XO) of the previous device. This output acts as a signal to the next device in the daisy chain by providing a pulse to the next device when the previous device reaches the last location of memory. Data outputs for 9-bit wide data. This data is in a high impedance condition whenever Read Enable (R) is in a HIGH state or the device is empty. FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO 4. External logic is needed to generate a composite Full Flag (FF) and Empty Flag (EF). This requires the ORing of all EFs and ORing of all FFs (i.e., all must be set to generate the correct composite FF or EF). 5. The Retransmit (RT) function and Half-Full Flag (HF) are not available in the Depth Expansion Mode. Bidirectional Mode OPERATING MODES Single Device Mode A single FIFO may be used when the application requirements are for the number of words in a single device. The FIFOs are in a Single Device Configuration when the Expansion In (XI) control input is grounded. In this mode the Half-Full Flag (HF), which is an active-low output, is the active function of the combination pin XO/ HF. 1. The first device must be designated by grounding the First Load (FL) control input. O 2. All other devices must have FL in the HIGH state. 3. The Expansion Out (XO) pin of each device must be tied to the Expansion In (XI) pin of the next device with the last device connecting back to the first. BS FIFO Products 3 03/04/99–LDS.8C201/2/3/4-H The FIFOs can easily be adapted to applications where the requirements are for greater than the number of words in a single device. Any depth can be attained by adding additional FIFOs. The FIFOs operates in the Depth Expansion configuration when the following conditions are met: O Depth Expansion (Daisy Chain) Mode LE Applications which require data buffering between two systems (each system capable of read and write Width Expansion Mode operations) can be achieved by pairing Word width may be increased simply FIFOs. Care must be taken to assure by connecting the corresponding input that the appropriate flag is monitored control signals of multiple devices. by each system (i.e., FF is monitored Status flags (EF, FF, and HF) can be on the device when W is used; EF is detected from any one device. Any monitored on the device when R is word width can be attained by adding used). Both Depth Expansion and additional FIFOs. Flag detection is Width Expansion may be used in this accomplished by monitoring the FF, mode. EF, and HF signals on either (any) device used in the width expansion configuration. Do not connect any output signals together. TE L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO MAXIMUM RATINGS Above which useful life may be impaired (Notes 1, 2) Storage temperature ........................................................................................................... –65°C to +150°C Operating ambient temperature ........................................................................................... –55°C to +125°C VCC supply voltage with respect to ground ............................................................................ –0.5 V to +7.0 V Input signal with respect to ground ........................................................................................ –0.5 V to +7.0 V Signal applied to high impedance output ............................................................................... –3.0 V to +7.0 V Output current into low outputs ............................................................................................................. 25 mA OPERATING CONDITIONS To meet specified electrical and switching characteristics ELECTRICAL CHARACTERISTICS Over Operating Conditions (Note 5) Symbol VOH VOL VIH Parameter Output High Voltage Output Low Voltage Input High Voltage Test Condition LE 40 90 30 95 25 100 20 110 4 TE Min 2.4 Typ 2.0 –0.5 L8C201/202/203/20415 120 12 150 Mode Active Operation, Commercial Active Operation, Industrial Active Operation, Military Temperature Range (Ambient) 0°C to +70°C –40°C to +85°C –55°C to +125°C Supply Voltage 4.5 V ≤ VCC ≤ 5.5 V 4.5 V ≤ VCC ≤ 5.5 V 4.5 V ≤ VCC ≤ 5.5 V L8C201/202/203/204 Max Unit V 0.4 VCC +0.3 0.8 V V VCC = 4.5 V, IOH = –2.0 mA VCC = 4.5 V, IOL = 8.0 mA VIL IIX IOZ ICC2 ICC3 CIN COUT Input Low Voltage Input Leakage Current Output Leakage Current O (Note 3) V µA µA mA mA pF pF Ground ≤ VIN ≤ VCC ±1 ±10 15 5 5 7 VCC Current, TTL Inactive VCC Current, CMOS Standby Input Capacitance Output Capacitance O Symbol ICC1 Parameter BS R ≥ VIH, GND ≤ VOUT ≤ VCC All Inputs = VIH MIN (Note 6) All Inputs = VCC (Note 12) Ambient Temp = 25°C, VCC = 4.5 V Test Frequency = 1 MHz (Note 9) Test Condition (Note 5) 10 180 Unit mA VCC Current, Active FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Commercial and Industrial Operating Range ASYNCHRONOUS AND RESET TIMING (ns) L8C201/202/203/204– 25 Symbol tRLRL tRLQV tRHRL tRLRH tRHQV tRHQZ tWLWL tWLWH tWHWL tDVWH tWHDX tSLSH tSLWL tWHSH tRHSH tSHWL tSLEL tSLHH tSLFH Parameter Read Cycle Time (MHz) Read Low to Output Valid (Access Time) Read High to Read Low (Notes 8, 9) Read Low to End of Read Cycle (Notes 8, 9) Read High to Output Valid Read High to Output High Z (Note 14) Write Cycle Time (Note 9) Write Low to Write High (Notes 8, 9) Write High to End of Write Cycle (Notes 8, 9) Data Valid to Write High (Notes 8, 9) Write High to Data Change (Notes 8, 9) Reset Cycle Time (Notes 9, 10) Reset Low to Write Low (Notes 9, 10) Write High to Reset High (Notes 9, 10) Read High to Reset High (Notes 9, 10) Reset High to Write Low (Notes 9, 10) Reset Low to Empty Flag Low Reset Low to Half-Full Flag High Reset Low to Full Flag High 10 25 5 20 Min 35 25 10 15 5 15 Max 15 Min 25 15 8 12 5 15 Max Min 20 12 5 10 5 15 15 10 5 8 0 10 15 10 10 5 12 12 12 10 10 10 12 Max 10 Min 15 10 Max LE 35 25 25 10 25 25 25 tRLRL tRHRL tRLRH tRLQV tRHQZ DATA-OUT VALID ASYNCHRONOUS READ R AND WRITE OPERATION tRLQV BS Q8-0 W D8-0 O tRHQV DATA-OUT VALID tWLWL tWLWH tWHWL tWHDX DATA-IN VALID tDVWH DATA-IN VALID RESET TIMING O tSLWL tSLSH tWHSH tSHWL RS W tRHSH R tSLEL EF tSLHH, tSLFH HF, FF 5 TE 35 25 10 15 0 25 15 10 10 0 20 12 8 8 0 25 15 25 15 15 10 15 15 15 12 20 12 12 8 FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Commercial and Industrial Operating Range FULL/EMPTY FLAG AND RETRANSMIT TIMING (ns) L8C201/202/203/204– 25 Symbol tRLQV tRLEL tRHFH tWHEH tWLFL tTLAL tTLTH tAHTH tTHAL Parameter Read Low to Output Valid (Access Time) Read Low to Empty Flag Low Read High to Full Flag High Write High to Empty Flag High Write Low to Full Flag Low Retransmit Cycle Time Retransmit Low to End of Retransmit Cycle (Notes 8, 9, 10) Read/Write High to Retransmit High (Notes 8, 9, 10) Retransmit High to Read/Write Low (Note 9) 35 Min Max 25 25 25 25 25 25 15 Min Max 15 15 15 15 15 20 Min 12 Max 12 12 12 12 12 15 10 10 5 10 Min Max 10 10 10 10 10 FULL FLAG FROM LAST WRITE TO FIRST READ LAST WRITE R W tWLFL FF EMPTY FLAG FROM LAST READ TO FIRST WRITE LAST READ W IGNORED READ O tWHEH tTLTH tAHTH 6 LE tRHFH FIRST WRITE ADDITIONAL WRITES tTLAL IGNORED WRITE FIRST READ ADDITIONAL READS R EF DATA OUT BS tRLEL tRLQV VALID O RETRANSMIT RT W, R HF, EF, FF TE 25 25 10 15 15 10 12 12 8 ADDITIONAL WRITES FIRST READ VALID tTHAL FLAG VALID FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Commercial and Industrial Operating Range FULL/HALF-FULL/EMPTY FLAG TIMING (ns) L8C201/202/203/204– 25 Symbol tRHFH tEHRH tRHHH tWHEH tWLHL tFHWH Parameter Read High to Full Flag High Read Pulse Width After Empty Flag High Read High to Half-Full Flag High Write High to Empty Flag High Write Low to Half-Full Flag Low Write Pulse Width After Full Flag High (Note 9) 25 25 25 25 25 15 Min Max 25 15 15 15 15 12 15 Min Max 15 12 12 12 12 10 Min 12 Max 12 10 10 10 10 10 Min Max 10 EMPTY FLAG TIMING W tWHEH EF LE O tRHFH MORE THAN HALF-FULL tWLHL 7 R FULL FLAG TIMING W FF R HALF-FULL FLAG TIMING BS HALF-FULL OR LESS O W R HF TE tEHRH tFHWH HALF-FULL OR LESS tRHHH FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Commercial and Industrial Operating Range EXPANSION TIMING (ns) L8C201/202/203/204– 25 Symbol tALOL tAHOH tXLXH tXHXL tALXL Parameter Read/Write to Expansion Out Low (Note 11) Read/Write to Expansion Out High (Note 11) Expansion In Pulse Width (Notes 9, 11) Expansion In High to Expansion In Low (Notes 9, 11) Read/Write Low to Expansion In Low (Notes 9, 11) 25 10 15 Min Max 25 25 15 10 12 15 Min Max 15 15 12 10 8 Min 12 Max 12 12 10 10 8 10 Min Max 12 12 EXPANSION OUT WRITE TO LAST PHYSICAL LOCATION W R tALOL XO tAHOH LE tALOL tXHXL tALXL READ FROM FIRST PHYSICAL LOCATION 8 EXPANSION IN tXLXH XI tALXL W WRITE TO FIRST PHYSICAL LOCATION R O BS O TE READ FROM LAST PHYSICAL LOCATION tAHOH FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Military Operating Range ASYNCHRONOUS AND RESET TIMING (ns) L8C201/202/203/204– 40 Symbol tRLRL tRLQV tRHRL tRLRH tRHQV tRHQZ tWLWL tWLWH tWHWL tDVWH tWHDX tSLSH tSLWL tWHSH tRHSH tSHWL tSLEL tSLHH tSLFH Parameter Read Cycle Time (MHz) Read Low to Output Valid (Access Time) Read High to Read Low (Notes 8, 9) Read Low to End of Read Cycle (Notes 8, 9) Read High to Output Valid Read High to Output High Z (Note 14) Write Cycle Time (Note 9) Write Low to Write High (Notes 8, 9) Write High to End of Write Cycle (Notes 8, 9) Data Valid to Write High (Notes 8, 9) Write High to Data Change (Notes 8, 9) Reset Cycle Time (Notes 9, 10) Reset Low to Write Low (Notes 9, 10) Write High to Reset High (Notes 9, 10) Read High to Reset High (Notes 9, 10) Reset High to Write Low (Notes 9, 10) Reset Low to Empty Flag Low Reset Low to Half-Full Flag High Reset Low to Full Flag High 10 40 5 25 Min 50 40 10 30 5 20 Max Min 40 30 10 20 5 15 30 20 10 12 0 20 30 20 20 10 40 40 40 30 30 30 30 Max 20 Min 30 20 Max LE tRLRL tRHRL tRLRH tRLQV tRHQZ DATA-OUT VALID ASYNCHRONOUS READ R AND WRITE OPERATION tRLQV BS Q8-0 W D8-0 O tRHQV DATA-OUT VALID tWLWL tWLWH tWHWL tWHDX DATA-IN VALID tDVWH DATA-IN VALID RESET TIMING O tSLWL tSLSH tWHSH tSHWL RS W tRHSH R tSLEL EF tSLHH, tSLFH HF, FF 9 TE 50 40 10 20 0 40 30 10 18 0 40 50 40 40 10 50 50 50 30 40 30 30 10 FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Military Operating Range FULL/EMPTY FLAG AND RETRANSMIT TIMING (ns) L8C201/202/203/204– 40 Symbol tRLQV tRLEL tRHFH tWHEH tWLFL tTLAL tTLTH tAHTH tTHAL Parameter Read Low to Output Valid (Access Time) Read Low to Empty Flag Low Read High to Full Flag High Write High to Empty Flag High Write Low to Full Flag Low Retransmit Cycle Time Retransmit Low to End of Retransmit Cycle (Notes 8, 9, 10) Read/Write High to Retransmit High (Notes 8, 9, 10) Retransmit High to Read/Write Low (Note 9) 50 40 40 10 Min Max 40 30 35 35 35 40 30 30 10 Min 30 Max 30 30 30 30 30 30 20 20 10 20 Min Max 20 20 20 20 20 FULL FLAG FROM LAST WRITE TO FIRST READ LAST WRITE R W tWLFL FF EMPTY FLAG FROM LAST READ TO FIRST WRITE LAST READ W IGNORED READ O tWHEH tTLTH tAHTH 10 LE tRHFH FIRST WRITE ADDITIONAL WRITES tTLAL IGNORED WRITE FIRST READ ADDITIONAL READS R EF DATA OUT BS tRLEL tRLQV VALID O RETRANSMIT RT W, R HF, EF, FF TE ADDITIONAL WRITES FIRST READ VALID tTHAL FLAG VALID FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Military Operating Range FULL/HALF-FULL/EMPTY FLAG TIMING (ns) L8C201/202/203/204– 40 Symbol tRHFH tEHRH tRHHH tWHEH tWLHL tFHWH Parameter Read High to Full Flag High Read Pulse Width After Empty Flag High Read High to Half-Full Flag High Write High to Empty Flag High Write Low to Half-Full Flag Low Write Pulse Width After Full Flag High (Note 9) 40 40 50 35 50 30 Min Max 35 30 40 30 40 20 Min 30 Max 30 20 30 20 30 20 Min Max 20 EMPTY FLAG TIMING W tWHEH EF LE O tRHFH MORE THAN HALF-FULL tWLHL 11 R FULL FLAG TIMING W FF R HALF-FULL FLAG TIMING BS HALF-FULL OR LESS O W R HF TE tEHRH tFHWH HALF-FULL OR LESS tRHHH FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO SWITCHING CHARACTERISTICS Over Military Operating Range EXPANSION TIMING (ns) L8C201/202/203/204– 40 Symbol tALOL tAHOH tXLXH tXHXL tALXL Parameter Read/Write to Expansion Out Low (Note 11) Read/Write to Expansion Out High (Note 11) Expansion In Pulse Width (Notes 9, 11) Expansion In High to Expansion In Low (Notes 9, 11) Read/Write Low to Expansion In Low (Notes 9, 11) 40 10 10 Min Max 40 40 30 10 10 Min 30 Max 30 30 20 10 10 20 Min Max 20 20 EXPANSION OUT WRITE TO LAST PHYSICAL LOCATION W R tALOL XO tAHOH LE tALOL tXHXL tALXL READ FROM FIRST PHYSICAL LOCATION 12 EXPANSION IN tXLXH XI tALXL W WRITE TO FIRST PHYSICAL LOCATION R O BS O TE READ FROM LAST PHYSICAL LOCATION tAHOH FIFO Products 03/04/99–LDS.8C201/2/3/4-H L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO FIGURE 1. FIFO MEMORY (DEPTH EXPANSION) BLOCK DIAGRAM W FF XO EF 9 9 R Q 8-0 V CC D 8-0 L8C20X XI FL XO 9 L8C20X XI FL 9 XO FF 9 EF 9 L8C20X XI FL RS TABLE 1. MODE Reset RESET AND RETRANSMIT (SINGLE DEVICE CONFIGURATION/WIDTH EXPANSION MODE) INPUTS RS 0 RT X 0 INTERNAL STATUS Write Pointer Location Zero Unchanged Increment EF 0 X X OUTPUTS FF 1 X X HF 1 X X XI 0 Read Pointer Retransmit Read/Write BS 1 0 1 1 0 INPUTS RT 0 1 (2) RS 0 0 1 XI TABLE 2. RESET AND FIRST LOAD TRUTH TABLE (DEPTH EXPANSION/COMPOUND EXPANSION MODE) INTERNAL STATUS Write Pointer Location Zero Location Zero Disabled X OUTPUTS EF 0 0 X FF 1 1 X Read Pointer O MODE Reset First Device Reset All Others Read/Write (1) (1) (1) (1) See Figure 1 (Depth Expansion Block Diagram) (2) Unchanged O Location Zero Location Zero Increment Location Zero X 13 Location Zero Disabled LE FIFO Products 03/04/99–LDS.8C201/2/3/4-H TE FULL FF EF EMPTY L8C201/202/203/204 DEVICES INCORPORATED 512/1K/2K/4K x 9-bit Asynchronous FIFO NOTES 1. Maximum Ratings indicate stress specifications only. Functional operation of these products at values beyond those indicated in the Operating Conditions table is not implied. Exposure to maximum rating conditions for extended periods may affect reliability of the tested device. 2. The products described by this specification include internal circuitry designed to protect the chip from damaging substrate injection currents and accumulations of static charge. Nevertheless, conventional precautions should be observed during storage, handling, and use of these circuits in order to avoid exposure to excessive electrical stress values. 3. This product provides hard clamping of transient undershoot. Input levels below ground will be clamped beginning at –0.6 V. A current in excess of 100 mA is required to reach –2 V. The device can withstand indefinite operation with inputs as low as –3 V subject only to power dissipation and bond wire fusing constraints. 4. “Typical” supply current values are not shown but may be approximated. At a VCC of +5.0 V, an ambient temperature of +25°C and with nominal manufacturing parameters, the operating supply currents will be approximately 3/4 or less of the maximum values shown. 5. Tested with outputs open and data inputs changing at the specified read and write cycle rate. The device is neither full or empty for the test. 6. Tested with outputs open in the worst static input control signal combination (i.e., W, R, XI, FL, and RS). 7. These parameters are guaranteed but not 100% tested. ments of all parts. Responses from the internal circuitry are specified from the point of view of the device. Access time, for example, is specified as a maximum since worst-case operation of any device always provides data within that time. 10. When cascading devices, the reset pulse width must be increased to equal tSLSH + tSLHH. 11. It is not recommended that Logic Devices and other vendor parts be cascaded together. The parts are designed to be pinfor-pin compatible but temperature and voltage compensation may vary from vendor to vendor. Logic Devices can only guarantee the cascading of Logic Devices parts to other Logic Devices parts. 12. Tested with output open and RS = FL = XI = R = W = VCC. FIGURE 2a. R 1 4 80 Ω +5 V OUTPUT INCLUDING JIG AND SCOPE 30 pF R2 255 Ω TE +5 V OUTPUT INCLUDING JIG AND SCOPE FIGURE 2b. R1 480Ω 14. Transition is measured ±200 mV from steady state voltage with specified loading in Fig. 2b. This parameter is sampled and not 100% tested. 15. This product is a very high speed device and care must be taken during testing in order to realize valid test information. Inadequate attention to setups and procedures can cause a good part to be rejected as faulty. Long high-inductance leads that cause supply bounce must be avoided by bringing the VCC and ground planes directly up to the contactor fingers. A 0.01 µF high frequency capacitor is also required between VCC and ground. To avoid signal reflections, proper terminations must be used. LE 14 13. At any given temperature and voltage condition, output disable time is less than output enable time for any given device. 5 pF R2 255Ω FIGURE 3. +3.0 V 10% 90% 90% 10%