SN65LVELT23: Signal is generated on OUTPUT when INPUTs are opened.

Yoonsun Kim

Part Number: SN65LVELT23

Hello,

The output pin is connected to GPIO of MCU and is interrupt source. The input pins are connected to external connector without any termination resistors, and external connector is opened.

I attached a picture, ch3/ch4 are input pins(+/-) and ch2 is output pin of SN65LVELT23.

As you see, unexpected signal is generated on output when inputs are opened and interrupt is generated continuously on MCU so that MCU looks like stalled.

I cannot find out why signal appears on output pin. Which point can I check?

over 8 years ago

0 Ikechukwu Anyiam over 8 years ago

TI__Mastermind 35130 points

Hi Yoonsun,

Have you seen this behavior on multiple units?

Regards,
I.K.

0 Yoonsun Kim over 8 years ago in reply to Ikechukwu Anyiam

Expert 1850 points

Hi I.K.

Three boards are assembled and at least two board have same problem. I didn't check third board because it is not in office.

Regards,

0 Ikechukwu Anyiam over 8 years ago in reply to Yoonsun Kim

TI__Mastermind 35130 points

Hi Yoonsun,

I have seen a similar issue with leaving inputs open on this device before. When I put 50-ohm terminators on unused inputs the output signal disappears. Are you able to try the same and see if that resolves the issue?

Regards,
I.K.

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SN65LVELT23: Signal is generated on OUTPUT when INPUTs are opened.