器件名称:
74HC148
功能描述:
8-LINE TO 3-LINE PRIORITY ENCODERS
文件大小:
127.38KB 共8页
简 介:
SN54HC148, SN74HC148 8-LINE TO 3-LINE PRIORITY ENCODERS SCLS109D – MARCH 1984 – REVISED MAY 1997 D D D Encode Eight Data Lines to 3-Line Binary (Octal) Applications Include: – n-Bit Encoding – Code Converters and Generators Package Options Include Plastic Small-Outline (D) and Ceramic Flat (W) Packages, Ceramic Chip Carriers (FK), and Standard Plastic (N) and Ceramic (J) 300-mil DIPs SN54HC148 . . . J OR W PACKAGE SN74HC148 . . . D OR N PACKAGE (TOP VIEW) description The ’HC148 feature priority decoding of the inputs to ensure that only the highest-order data line is encoded. These devices encode eight data lines to 3-line (4-2-1) binary (octal). Cascading circuitry (enable input EI and enable output EO) has been provided to allow octal expansion without the need for external circuitry. Data inputs and outputs are active at the low logic level. The SN54HC148 is characterized for operation over the full military temperature range of –55°C to 125°C. The SN74HC148 is characterized for operation from –40°C to 85°C. 4 5 6 7 EI A2 A1 GND 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VCC EO GS 3 2 1 0 A0 SN54HC148 . . . FK PACKAGE (TOP VIEW) 5 4 NC VCC EO 6 7 NC EI A2 4 5 6 7 8 3 2 1 20 19 18 17 16 15 14 9 10 11 12 13 GS 3 NC 2 1 NC – No internal connection FUNCTION TABLE INPUTS EI H L L L L L L L L L 0 X H X X X X X X X L 1 X H X X X X X X L H 2 X H X X X X X L H H 3 X H X X X X L H H H 4 X H X X X L H H H H 5 X H X X L H H H H H 6 X H X L H H H H H H 7 X H L H H H H H H H A2 ……
