器件名称:
MC74AC256N
功能描述:
DUAL 4-BIT ADDRESSABLE LATCH
文件大小:
232.02KB 共7页
简 介:
MC74AC256 MC74ACT256 Dual 4Bit Addressable Latch The MC74AC256/74ACT256 dual addressable latch has four distinct modes of operation which are selectable by controlling the Clear and Enable inputs (see Function Table). In the addressable latch mode, data at the Data (D) inputs is written into the addressed latches. The addressed latches will follow the Data input with all unaddressed latches remaining in their previous states. In the memory mode, all latches remain in their previous states and are unaffected by the Data or Address inputs. To eliminate the possibility of entering erroneous data in the latches, the enable should be held HIGH (inactive) while the address lines are changing. In the dual 1-of-4 decoding or demultiplexing mode (MR = E = LOW), addressed outputs will follow the level of the D inputs with all other outputs LOW. In the clear mode, all outputs are LOW and unaffected by the Address and Data inputs. Combines Dual Demultiplexer and 8-Bit Latch Serial-to-Parallel Capability Output from Each Storage Bit Available Random (Addressable) Data Entry Easily Expandable Common Clear Input Useful as Dual 1-of-4 Active HIGH Decoder VCC 16 MR 15 E 14 Db 13 Q3b 12 Q2b 11 Q1b 10 Q0b 9 DUAL 4-BIT ADDRESSABLE LATCH N SUFFIX CASE 648-08 PLASTIC D SUFFIX CASE 751B-05 PLASTIC 1 A0 2 A1 3 Da 4 Q0a 5 Q1a 6 Q2a 7 Q3a 8 GND LOGIC SYMBOL Db Da A0 E MR A1 Q0a Q1a Q2a Q3a Q0b Q1b Q2b Q3b FACT DATA 5-1 MC74AC256 MC74ACT256 MODE SELECT-FUNCTION TABLE Operating Mo……
