These 9-bit latches are designed specifically for storing the contents of the input data bus plus providing the capability of reading-back the stored data onto the input data bus. In addition, they provide a 3-state buffer-type output and are easily implemented in parity applications.
The nine latches of the 74ALS993 are transparent D-type. While enable (C) is high, the Q outputs will provide the complement of what is applied to its data (D) outputs. On both devices, the Q outputs will be in the 3-state condition when output enable OEQ is high.
Read-back is provided through the read-back control input. When the control is taken low, the data present at the output of the data latches will be allowed to pass back onto the input data bus. When it is taken high, the output of the data latches will be isloated from the data (D) inputs. The read-back control does not aggect the internal operation of the latches; however, precautions should be taken not to create a bus conflict situation. The 74ALS993 is characterized for operation from 0°C to 70°C.
3-State I/O-Tyoe Inputs
Designed with 9 Bits for Parity Applications
24 pin DIP. Actual brand may vary from picture.