Level Shifter - 8 Channel (TXS01018E) Hookup Guide

2022-07-28 | By SparkFun Electronics

License: See Original Project

Courtesy of SparkFun

Guide by EL DUDERINO

Introduction

The SparkFun Level Shifter - 8 Channel (TXS0108E) features the TXS0108E™ 8-bit, bi-directional ‎logic level translator from Texas Instruments to shift between devices running at different common ‎microcontroller voltages such as 1.8V, 3.3V, and 5V. The TXS0108E can transmit data between ‎ports at max speeds of 110Mbps (push/pull) or 1.2Mbps (open drain) so you can use a 3.3V SPI ‎device with a 5V microcontroller like the SparkFun RedBoard Plus without sacrificing data ‎transmission speeds.‎

SparkFun Level Shifter - 8 Channel (TXS0108E)‎

In this guide we'll go over the specifications of the TXS0108E and how to wire it into a level shifting ‎circuit.‎

Required Materials

In order to follow along with this guide you'll need the devices you want to level shift between along ‎with the TXS0108E Breakout. The example circuit in the Hardware Assembly section uses the ‎following items to demonstrate shifting from a 5V microcontroller to a 3.3V SPI device:‎

SparkFun RedBoard Plus

SparkFun Triple Axis Accelerometer Breakout - KX134 (Qwiic)‎

Required Tools

Using this breakout requires through-hole soldering so you may need some of the following tools ‎and soldering accessories:‎

Recommended Reading

This tutorial assumes readers have some know-how about the topics in the tutorials below. If you ‎are not familiar with the concepts covered in them or need a refresher, we recommend reading ‎through them before continuing with this guide:‎

How to Solder: Through-Hole Soldering: This tutorial covers everything you need to ‎know about through-hole soldering.‎
Working with Wire: How to strip, crimp, and work with wire.‎
How to Use a Breadboard: Welcome to the wonderful world of breadboards. Here we will ‎learn what a breadboard is and how to use one to build your very first circuit.‎
What is an Arduino? What is this 'Arduino' thing anyway? This tutorial dives into what an ‎Arduino is and along with Arduino projects and widgets.‎
Logic Levels: Learn the difference between 3.3V and 5V devices and logic levels.‎

Hardware Overview

Let's take a closer look at the TXS0108E level shifting IC and other components on this breakout.‎

TXS0108E Level Shifter

The TXS0108E is an 8-channel, bi-directional, level shifting voltage translator that works in both ‎open drain and push/pull operations. It accepts a supply voltage range of 1.4V to 3.6V on the A Port ‎and 1.65V to 5.5V on the B Port (VCC_A ≤ VCC_B).‎

board_1

The TXS0108E uses pass gate circuit architecture with integrated edge rate (one shot) accelerators ‎to support data transmission speeds up to 1.2Mbps in open drain operation and up to 110Mbps in ‎push/pull operation. It also has built in pull-up resistors for open drain applications so external ‎resistors are not necessary. For complete information on the TXS0108E, refer to the datasheet.‎

PTH Headers

The board breaks out all the TXS0108E's pins to a pair of 0.1"-spaced PTH headers; one for each ‎port. The OE input pin is also broken out on the Port A "side" as it is referenced to VCCA. The ‎board pulls OE LOW through a 110kΩ resistor to disable the I/O pins by default. Make sure to tie the ‎OE pin to VCCA to enable the device.‎

headers_2

Board Dimensions

The SparkFun Level Shifter - 8 Channel (TXS0108E) measures 1.10" x 0.50" (27.94mm x ‎‎12.70mm).‎

dim_3

Hardware Assembly

In this section we'll demonstrate how to assemble this breakout into a level-shifting circuit between ‎a 5V development board, the RedBoard Plus, and a 3.3V SPI device, the SparkFun Triple Axis ‎Accelerometer Breakout - KX134 (Qwiic). We'll use a breadboard here to make building the level ‎shifting circuit easier and to keep the connections as short as possible.‎

Soldering Assembly

This breakout requires some through-hole soldering to integrate the board into a level-shifting ‎circuit. Since the demo circuit uses a breadboard, we'll solder a set of breakaway male headers to ‎the board so we can easily plug it into the breadboard.

soldering_4

Arduino Assembly

Plug the Level Shifter Breakout into the breadboard and then make connections to the board with ‎wires. Leave the circuit unpowered while building the circuit to avoid damaging anything with a short ‎or improper connection.

assembly_5

Reminder, VCC_A must be less than or equal to VCC_B and OE needs to connect to VCC_A. Our ‎SPI device runs at 3.3V so we connect the peripheral pins to channels on Port A and connect ‎matching microcontroller signals to Port B.‎

Troubleshooting

Signal Oscillations

Some users may experience oscillations or "ringing" on communication lines (e.g., SPI/I²C) that can ‎inhibit communication between devices. Capacitance or inductance on the signal lines can cause ‎the TXS0108E's edge rate accelerators to detect false rising/falling edges.‎

When using the TXS0108E, we recommend keeping your wires between devices as short as ‎possible as during testing we found even a 6" wire like our standard jumper wires can cause this ‎oscillation problem. Also make sure to disable any pull-up resistors on connected devices. When ‎level shifting between I/O devices, this shifter works just fine over longer wires.‎

The TXS0108E is designed for short distance, high-speed applications so if you need a level ‎shifter for a communication bus over a longer distance, we recommend one of our other level ‎shifters.‎

Voltage Requirements and OE

Reminder, voltage supplied to VCC_A must be less than or equal to VCC_B. Also, the breakout ‎pulls OE LOW so make sure to tie the OE pin to VCC_A to enable the TXS0108E.‎

General Troubleshooting

Not working as expected and need help? ‎

If you need technical assistance and more information on a product that is not working as you ‎expected, we recommend heading on over to the SparkFun Technical Assistance page for some ‎initial troubleshooting.

SPARKFUN TECHNICAL ASSISTANCE PAGE‎ ‎

If you don't find what you need there, the SparkFun Forums are a great place to find and ask for ‎help. If this is your first visit, you'll need to create a Forum Account to search product forums and ‎post questions.

CREATE NEW FORUM ACCOUNT LOG INTO SPARKFUN FORUMS

Resources and Going Further

For more information about this breakout, check out the following resources:‎