TXB0108 level converter breakout board

in ARM by DP | 4 comments

Have loads of 5 volt hardware you can’t use with your new 3.3 volt Stellaris Launchpad (or other hardware)? Mike solved this problem by building a level converter using two TXB0108 ICs

And here is the proof that it works. I’m driving a 5V graphic LCD using the 3.3v Stellaris Launchpad. The TXB0108 level converters have two voltage inputs. The lower voltage goes to VCCA and the higher voltage goes to VCCB. Each chip provides eight pins on either side for easy connections.

Via the contact form.

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Comments

  1. Peter says:

    Level shifting to drive LCDs is probably not necessary. The signals are unidirectional from the Stellaris to the LCD, so you don’t have to worry about protecting the Stellaris pins (although you can put a clamping diode to 3.3V for grins and giggles). Looking at the electrical specs for the Stellaris, the HI minimum output voltage is 2.4 and the minimum LO is 0.4. I don’t know about your particular LCD but taking one from Sparkfun for example (http://www.sparkfun.com/products/256), the HI input min is 2.2 and the LO input max is 0.6 so you have 200 mV of room on both sides.

  2. cubeberg says:

    Pins on the Stellaris are 5v tolerant as well – so there’s no need to protect the pins when reading from 5v devices either.

  3. J. Peterson says:

    Rather than roll your own boards, you can buy TBX0108 breakouts from Adafruit:

    http://www.adafruit.com/products/395

  4. katjap says:

    what cubeberg said. still generally useful though.

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