CD74HCT245

具有三态输出的高速 CMOS 逻辑同向八路总线收发器

The CD54HC245, CD54HCT245, and CD74HC245, are high-speed octal three-state bidirectional transceivers intended for two-way asynchronous communication between data buses. They have high drive current outputs which enable high-speed operation while driving large bus capacitances. They provide the low power consumption of standard CMOS circuits with speeds and drive capabilities comparable to that of LSTTL circuits.

The CD54HC245, CD54HCT245, CD74HC245 and CD74HCT245 allow data transmission of the B bus or from the B bus to the A bus. The logic level at the direction input DIR determines the direction. The output enable input OE\\, when high, puts the I/O ports in the high-impedance state.

The HC/HCT245 is similar in operation to the HC/HCT640 and the HC/HCT643.

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Buffered Inputs

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Three-State Outputs

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Bus Line Driving Capability

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Typical Propagation Delay A to B, B to A 9ns 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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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