器件名称: HD74HC679
功能描述: 12-bit Address Comparator
文件大小: 67.9KB 共10页
简 介:HD74HC679
12-bit Address Comparator
Description
The HD74HC679 address comparator simplifies addressing of memory boards and/or other peripheral devices. The four P inputs are normally hard wired with a preprogrammed address. An internal decoder determines what input information applied to the 12 A inputs must be low or high to cause a low state at the output (Y). For example, a positive-logic bit combination of 0111 (decimal 7) at the P input determines that inputs A1 through A7 must be low and that inputs A8 through A12 must be high to cause the output to go low. Equality of the address amplified at the A inputs to the preprogrammed address is indicated by the output being low. The HD74HC679 features and enable input (G). When G is low, the device is enabled. When G is high, the device is disabled and the output is high regardless of the A and P inputs.
Features
High Speed Operation: tpd (A to Y) = 18 ns typ (CL = 50 pF) High Output Current: Fanout of 10 LSTTL Loads Wide Operating Voltage: VCC = 2 to 6 V Low Input Current: 1 A max Low Quiescent Supply Current: ICC (static) = 4 A max (Ta = 25°C)
HD74HC679
Function Table
Inputs G L L L L L L L L L L L L L L L L L H P3 L L L L L L L L H H H H H H H H P2 L L L L H H H H L L L L H H H H P1 L L H H L L H H L L H H L L H H P0 L H L H L H L H L H L H L H L H A1 H L L L L L L L L L L L L X X L A2 H H L L L L L L L L L L L X X L A3 H H H L L L L L L L L L L X X L A4 H H H H L L L L L L L L L X X L A5 H H H H H L L L L L L L L……
