CD74HC251

具有三态输出的高速 CMOS 逻辑 8 输入多路复用器

The ’HC251 and ’HCT251 are 8-channel digital multiplexers with three-state outputs, fabricated with high-speed silicon-gate CMOS technology. Together with the low power consumption of standard CMOS integrated circuits, they possess the ability to drive 10 LSTTL loads. The three-state feature makes them ideally suited for interfacing with bus lines in a bus-oriented system.

This multiplexer features both true Y and complement Y\\ outputs as well as an output enable OE\\ input. The OE\ must be at a low logic level to enable this device. When the OE\ input is high, both outputs are in the high-impedance state. When enabled, address information on the data select inputs determines which data input is routed to the Y and Y\ outputs. The ’HCT251 logic family is speed, function, and pin-compatible with the standard ’LS251.

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Selects One of Eight Binary Data Inputs

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Three-State Output Capability

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True and Complement Outputs

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Typical Data to Output Propagation Delay of 14ns at VCC = 5V, CL = 15pF, TA = 25°C

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Fanout Over Temperature Range

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Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads

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Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads

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Wide Operating Temperature Range . . . -55°C to 125°C

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Balanced Propagation Delay and Transition Times

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Significant Power Reduction Compared to LSTTL Logic ICs

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Alternate Source is Philips

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HC Types

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2V to 6V Operation

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High Noise Immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5V

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HCT Types

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4.5V to 5.5V Operation

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Direct LSTTL Input Logic Compatibility, VIL = 0.8V Max, VIH = 2V Min

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CMOS Input Compatibility, Il 1µA at VOL, VOH