1
\$\begingroup\$

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.

\$\endgroup\$
1
  • \$\begingroup\$ You'll have two things driving the same line, that's not a good idea. \$\endgroup\$
    – Hearth
    Commented Jul 19, 2021 at 4:25

2 Answers 2

Reset to default
3
\$\begingroup\$

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

\$\endgroup\$
1
  • 1
    \$\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\$
    – saikumarkanikatla
    Commented Jul 20, 2021 at 8:46
2
\$\begingroup\$

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

\$\endgroup\$
1
  • \$\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\$
    – saikumarkanikatla
    Commented Jul 20, 2021 at 8:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.