SN74ALS990是TI公司的一款D类锁存器产品，SN74ALS990是八路 D 类透明读回锁存器，本页介绍了SN74ALS990的产品说明、应用、特性等，并给出了与SN74ALS990相关的TI元器件型号供参考。
SN74ALS990 - 八路 D 类透明读回锁存器 - D类锁存器 - 触发器/锁存器/寄存器 - TI公司（Texas Instruments，德州仪器）
This 8-bit latch is designed specifically for storing the contents of the input data bus and providing the capability of reading back the stored data onto the input data bus.
The eight latches are transparent D-type latches. While the latch-enable (LE) input is high, the Q outputs follow the data (D) inputs.
Read back is provided through the output-enable () input. When is taken low, the data present at the output of the data latches is allowed to pass back onto the input data bus. When is taken high, the output of the data latches is isolated from the D inputs. does not affect the internal operation of the latches; however, precautions should be taken not to create a bus conflict.
The SN74ALS990 is characterized for operation from 0°C to 70°C.
- 3-State I/O-Type Read-Back Inputs
- Bus-Structured Pinout
- True Logic Outputs
- Package Options Include Plastic Small-Outline (DW) Packages and Standard Plastic (N) 300-mil DIPs
