Complex translation made simple


This post was co-written by Dave Long and Jose Gonzalez

Connecting devices to one another has gone from a cool idea to a must-have. From activity trackers to smart homes, we see the need for more data to be exchanged among numerous types of devices and systems. In most, if not all, of these cases this data interaction needs to happen at a very high rate of speed and in some cases in multiple directions. So when you need to implement a controller or logic device to handle this communication you will usually run into the challenge of interfacing to different voltage levels. A common solution is to employ a voltage level translator. However, if you require multiple different voltages and directions, then the need for a multi-voltage, bi-directional translator arises. 

Let me introduce you to TI’s latest and greatest multi-voltage, bi-directional level translator LSF010x family. These 1/2/8 bit voltage level translators enable high-speed interfaces of >100MHz such as MDIO, SDIO, SMBUS and UART while translating multiple voltages, up or down, in multiple directions. This gives flexibility to work with any logic voltage level between 1V and 5V enabling a large number of devices that can be interfaced with little to no hassle.

When choosing a level translator like this, here are some design challenges you may run into:

Need to address multiple signals at multiple voltage levels

When interfacing with multiple signals at different voltage levels, this can create a complex system requirement where multiple translators need to be used for separate signals and voltages. The LSF010x family allows each bit to translate separately at multiple voltage levels, simplifying the complex system to a single device solution. Figure #3 shows an example of multi-voltage translation to multiple interfaces from 1.8V to two separate 3.3V and 5V systems.

Figure 1: Multiple interface translation

My data needs to flow in both directions, need for bi-directional support

When a controller needs to send and receive data to a bi-directional interface such as SMBUS. The LSF010x family will support bi-directional translation without the need for a direction control pin, allowing data to flow to and from any logic device. In figure 2 check out the LSF0102 translating a 1.8V MDIO interface signal to a 3.3V MDIO signal.

Figure 2: 1.8V to 3.3 MDIO translation

Need translation to occur at high speeds, very low delay

In applications that require high speed interfaces such as MDIO and SDIO, the LSF010X family can support frequencies greater than 100MHz and support less than 1.5ns propagation delay. As can be seen in Figure 3, the LSF010X family can translate a 3.3V signal down to 1.8V in a 160Mhz signal.

Figure 3: 3.3V to 1.8V high-speed translation

Very space constrained system

If your application or board is limited on space or has a constraint, using an integrated solution is paramount to reducing this space. This family is available in four different package types with sizes as small as 1.5mm x 1mm.

So, when the need arises for high speed, bi-directional, multi-voltage level translation the LSF010X family of devices can assist you in simplifying your design with a cost effective, small form factor solution.

 For more information:

Sample the LSF010X family

Check out the LSF010x datasheet

Buy the LSF010x evaluation module

  • How do these new parts compare to the existing TXS01xx and TXB01xx level translators?

  • I get samples of LSF0108 in TSSOP20 (thanks). A small card has been wired with a "very small ground plane", power supplies and ground are rather noisy. The translation is made from a 74AC logic 3.3V to 74AC logic in 5V. on this evaluation card to simulate old components on a card. In single pulse (1us width for 10 us period ) the component works pretty well. good translation from 3.3V to 5V with 1.5K Rpu, 5V input CMOS level as well as TTL input level are correct. translation from 5V to 3.3V offers a good protection to 3.3V component with a ripple not exceeding -0.5V to 4V. The problem i see is when i want to test a 50% duty cycle 30 MHz clock In that case translation is quasi stopped. What i see is VREFB and EN at less than 2V (220Kohms and 10n used as on the schematic). The only method i find to obtain a pretty good translation in that case consist to replace 220 Kohms with a 1.5 Kohms so that VREFB and EN work at 4.3V as with 220 Kohms in static. Is it a good solution ? Is it possible to connect VREFB directly to 5V and use 220K and 10n only for EN as on the schematic ?