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

應用 Application

? Desktop

簡介

MC74HC259A屬于集成電路（IC）的鎖存器。由制造生產(chǎn)的MC74HC259A鎖存器鎖存器是類似于觸發(fā)器的基本數(shù)字存儲設備，但是不同之處在于，在鎖存使能（或類似命名）信號處于有效邏輯狀態(tài)的任何時間，保持的邏輯狀態(tài)都可以改變。“透明”鎖存器還允許設備輸出在鎖存使能信號有效時反映輸入的當前狀態(tài)，而相反的是，狀態(tài)僅在保持狀態(tài)已固定時改變。