MC74HC259A数据手册集成电路（IC）的锁存器规格书PDF

描述 Description

The MC74HC259A is identical in pinout to the LS259. The device inputs are compatible with standard CMOS outputs; with pullup resistors, they are compatible with LSTTL outputs. The HC259A has four modes of operation as shown in the mode selection table. In the addressable latch mode, the data on Data In is written into the addressed latch. The addressed latch follows the data input with all non addressed latches remaining in their previous states. In the memory mode, all latches remain in their previous state and are unaffected by the Data or Address inputs. In the one of eight decoding or demultiplexing mode, the addressed output follows the state of Data In with all other outputs in the LOW state. In the Reset mode all outputs are LOW and unaffected by the address and data inputs. When operating the HC259A as an addressable latch, changing more than one bit of the address could impose a transient wrong address. Therefore, this should only be done while in the memory mode.

特性 Features

• Output Drive Capability: 10 LSTTL Loads
• Outputs Directly Interface to CMOS, NMOS, and TTL
• Operating Voltage Range: 2 to 6 V
• Low Input Current: 1 A
• High Noise Immunity Characteristic of CMOS Devices
• These are PbFree Devices

应用 Application

• Desktop

简介

MC74HC259A属于集成电路（IC）的锁存器。由制造生产的MC74HC259A锁存器锁存器是类似于触发器的基本数字存储设备，但是不同之处在于，在锁存使能（或类似命名）信号处于有效逻辑状态的任何时间，保持的逻辑状态都可以改变。“透明”锁存器还允许设备输出在锁存使能信号有效时反映输入的当前状态，而相反的是，状态仅在保持状态已固定时改变。