74HC540 Octal 3 state Inverting Buffer IC (74540) DIP 20 Package

74HC540 Octal 3 state Inverting Buffer IC (74540) DIP 20 Package

The 74HC540 is a high-speed CMOS octal (8-bit) inverting buffer/line driver featuring 3-state (tri-state) outputs. It is typically used to drive data buses or interface between logic circuits where signal inversion and bus isolation are required.

This IC inverts the input signals and can enable or disable all outputs simultaneously via two active-LOW enable pins (OE1 and OE2). When the enables are HIGH, all outputs go to a high-impedance (Hi-Z) state, effectively disconnecting them from the circuit — ideal for bus-oriented systems.

Built on 74HC high-speed CMOS technology, it offers low power consumption, high noise immunity, and fast switching speeds.

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Specifications:-

• Package Type:            DIP
• Voltage Rating:           2 to 6V
• Temperature Rating:    -40 to 85 Deg C
• Number of Pins:          20
• Output Current:           6mA
• Propagation Delay:      12ns

Functional Description

• The A1–A8 pins are data inputs.
• The corresponding Y1–Y8 pins are the inverted outputs.
• OE1 and OE2 are active-LOW enables:
• When OE1 = LOW and OE2 = LOW, the outputs are active (inverted).
• When either OE1 or OE2 is HIGH, all outputs are in high-impedance (Hi-Z) state.
• This feature allows the 74HC540 to act as a bus driver, connecting or disconnecting multiple devices from a shared data bus.

Applications

• Bus driver or line driver in microprocessor systems
• Logic level inversion
• Data buffering and isolation
• Peripheral interface circuits
• Memory address or data bus control
• LED or signal driving with inversion
• Signal multiplexing and control in digital systems

74hc540-ic-datasheet