SN65HVD08D

Introduction

The SN65HVD08D is an integrated circuit used as a bidirectional signal-level-shifting solution. This half-duplex transceiver includes an integrated charge pump, which uses four small 0.1 μF capacitors to generate 5.0V supply voltage, and four open-drain buffers. This device is useful primarily when one of the system is supplied by 3.3V and the other one is supplied by 5V, or in single-voltage 3.3V systems. It is a perfect match for IEEE-1284 parallel port applications, SCSI, and level-shifting between 1.5V and 3.3V signals. In this article, the application field and working principle of the SN65HVD08D will be discussed.

Application Field

The SN65HVD08D provides a high-speed, low-power level-shifting solution, which is ideal for interfacing devices that work with different voltage levels. It can be used, for example, in the following applications:

• IEEE-1284 Parallel Port Interfaces: The device is designed to interface with peripheral devices that are equipped with 25-pin D-sub connectors. The SN65HVD08D is a perfect choice for reliable speed up to 40 Mbps.
• SCSI Communications: SCSI (Small Computer Systems Interface) is a bus used for connecting computers, printers and other peripherals. The SN65HVD08D is a suitable solution for high-speed SCSI applications that require reliable operation at low power consumption.
• Level-shifting from 1.5V to 3.3V: The device is designed to level-shift digital signals between 1.5V and 3.3V or 3.3V to 5V and vice versa.
• Low-power Data Acquisition Applications: The SN65HVD08D is suitable for data acquisition and other low-power applications where a low cost and low power consumption solution is required.

Working Principle

The SN65HVD08D includes four open-drain buffers, two on each of the pins labeled A and B, that switch between the low and high level voltage sources depending on the logic level of the logic input signal. Each open-drain buffer can drive either the lower voltage source or the higher voltage source, but not both at the same time. The device also has an internal charge pump, which is capable of generating a 5V supply voltage from a 3.3V supply. The charge pump is used to ensure that the output voltages are properly matched with the input voltages.

When the logic input voltage is low, the output voltage of the A and B buffers will be sourced from the lower voltage source. When the logic input voltage is high, the output voltage of the A and B buffers will be sourced from the higher voltage source. The SN65HVD08D also includes a level-shifting circuit, which is used to level-shift digital signals between 1.5V and 3.3V or 3.3V to 5V and vice versa.

Conclusion

The SN65HVD08D is an integrated circuit used as a bidirectional signal-level-shifting solution. It is suitable for a wide range of applications, including IEEE-1284 parallel port interfaces, SCSI communication and level-shifting between 1.5V and 3.3V signals. The device includes four open-drain buffers and an internal charge pump, which enables it to generate a 5V supply voltage from a 3.3V supply. This makes the SN65HVD08D an excellent choice for high-speed and low-power data acquisition applications.