MC74VHCT240ADWRG

The MC74VHCT240ADWRG is a 16-pin digital logic device with 3-state Non-Inverting Buffer/Driver outputs. It can be used as a buffer or a reversible digital switch. The device supports 5.0 V, 3.3 V and 2.5 V voltage levels.

The MC74VHCT240ADWRG has eight buffer/drivers with input resistors and series resistors to reduce overshoot and undershoot. The device has an active-low output enable input for each buffer. The device has a Schmitt trigger input to increase noise rejection and improve input pulse qualification. It also has bus hold/bus release resistance for improved hold/release characteristics. The device also features an active-low overall enable pin.

Application Field and Features

The MC74VHCT240ADWRG belongs to the Logic - Buffers, Drivers, Receivers, Transceivers category. The main application fields are:

• Peripheral system interface between microprocessor and memory devices
• High-speed bus switches
• Analog multiplexers
• Data transmission

The main features of the MC74VHCT240ADWRG are:

• Low-voltage CMOS technology
• High-speed operation
• Low power-dissipation
• Fine-pitch SOIC package
• 5.0V tolerant inputs
• Schmitt trigger input capability
• Bus hold/bus release features

Working Principle

The MC74VHCT240ADWRG is a logic buffer/driver. The device takes an input signal, buffers it and drives the output to either logic 0 or logic 1 level depending on the input signal level. The logic buffer/driver has a low Enable pin (ENL) and high Enable pin (ENH) which are connected to an active low output enable signal. When the output enable signal is low, the buffer/driver is disabled and the outputs remain in the high impedance state. When the output enable signal is high, the buffer/driver is enabled and the outputs are driven either to logic 0 or logic 1 level depending on the input.

The device also features Schmitt trigger inputs which helps to improve the noise rejection capability and improve input pulse qualification. The Schmitt trigger input has some hysteresis, when the input rises above the trigger point, the output will be driven to logic 1 and when the input falls below the trigger point, the output will be driven to logic 0. The Schmitt trigger also helps to reduce the glitches caused by the noise present in the input signal.

The device also has a bus hold/bus release capability. When the device is enabled, any input that is in floating state is held in either logic 0 or logic 1 levels and when the device is disabled, the outputs are released allowing the inputs to go to its natural state.

Conclusion

The MC74VHCT240ADWRG is a logic buffer/driver based on low-voltage CMOS technology, designed for use in peripheral system interface between microprocessor and memory devices, high-speed bus switches, analog multiplexers and data transmission. The Schmitt trigger input and bus hold/bus release features helps to provide an improved noise rejection and improved input pulse qualification.