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I am using a level translator in my design to interface between two systems. I also want an option to bypass the level translator by shorting a jumper resistor placed across terminals A and B.

What happens when I place the jumper when the level translator is assembled? Is it advisable to use it that way or do I have to keep the level translator as DNP when the jumper is placed? The translator I am using is the SN74AVC1T45.

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  • \$\begingroup\$ You'll have two things driving the same line, that's not a good idea. \$\endgroup\$
    – Hearth
    Jul 19, 2021 at 4:25

2 Answers 2

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Pull-down only level converters like NXP AN10441 can be bypassed in such a way,

but a level converter that contains a gain stage and has no tri=state (High-Z) option is not going to play nicely with output connected to input.

I'd look for a way to overlap your jumper with the outline of the SN74AVC1T45 so that only one of them can be placed at a time. there appears to be room for an 0805 (or smaller) resistor (or jumper) between pads 3 and 4

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  • \$\begingroup\$ I will consider this in my next design as I am using the DSBGA package currently and I cannot remove the IC every time I want to bypass the level translator. \$\endgroup\$ Jul 20, 2021 at 8:50
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If you have either Vcc at GND, the chip the outputs are guaranteed to be in high-Z mode and you can have jumpers across it. I suggest a pull-down resistor and a jumper to Vcc.

enter image description here

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  • \$\begingroup\$ Thank you for the answer. I will consider using a pull-down resistor and a jumper to Vcc. I think this will solve my problem. \$\endgroup\$ Jul 20, 2021 at 8:46

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