SN74ACT7814 Datasheet | Texas Instruments

description A FIFO memory is a storage device that allows data to be written into and read from its array at independent data rates. The SN74ACT7814 is a 64-word by 18-bit FIFO for high speed and fast access times. It processes data at rates up to 50 MHz and access times of 15 ns in a bit-parallel format. Data is written into memory on a low-to-high transition at the load clock (LDCK) input and is read out on a low-to-high transition at the unload clock (UNCK) input. The memory is full when the number of words clocked in exceeds the number of words clocked out by 64. When the memory is full, LDCK signals have no effect on the data residing in memory. When the memory is empty, UNCK signals have no effect. DL PACKAGE (TOP VIEW) RESET 1 D17 2 D16 3 D15 4 D14 5 D13 6 D12 7 D11 8 D10 9 VCC 10 D9 11 D8 12 GND 13 D7 14 D6 15 D5 16 D4 17 D3 18 D2 19 D1 20 D0 21 HF 22 PEN 23 AF/AE 24 LDCK 25 NC 26 NC 27 FULL 28 56 OE 55 Q17 54 Q16 53 Q15 52 GND 51 Q14 50 VCC 49 Q13 48 Q12 47 Q11 46 Q10 45 Q9 44 GND 43 Q8 42 Q7 41 Q6 40 Q5 39 VCC 38 Q4 37 Q3 36 Q2 35 GND 34 Q1 33 Q0 32 UNCK 31 NC 30 NC 29 EMPTY Status of the FIFO memory is monitored by the full (FULL), empty (EMPTY), half-full (HF), and almost-full/almost-empty (AF/AE) flags. The FULL output is low when the memory is full and high when the memory is not full. The EMPTY output is low when the memory is empty and high when it is not empty. The HF output is high when the FIFO contains 32 or more words and is low when it contains 31 or fewer words. The AF/AE status flag is a programmable flag. The first one or two low-to-high transitions of LDCK after reset are used to program the almost-empty offset value (X) and the almost-full offset value (Y) if program enable (PEN) is low. The AF/AE flag is high when the FIFO contains X or fewer words or (64 - Y) or more words. The AF/AE flag is low when the FIFO contains between (X + 1) and (63 - Y) words. Please be aware that an important notice concerning availability, standard...