THVD1552: Can THVD1552 be drop in replacement SN75LBC180?

Hi Nicky,

I wouldn't expect any circuit changes to be needed. What exactly do you mean when you say that TX doesn't work? Are you seeing a static voltage output on pins Z and Y (and if so, what voltage), or are you seeing distorted waveforms? Can you please provide an oscilloscope capture showing the issue so that we can better understand it and help to debug?

Thanks,
Max

Hi Max,

Solved this problem.
There are 2 Vcc pins, but remains one pin (Pin 13) as NC by mistake.
After connect pin 13 to Vcc, this problem disappeared.

One question,
According to datasheet, two Vcc pins (pin 13 & pin 14) are connected internally.
Why this kind of problem occurred, when one Vcc pin (pin 13) is not conneccted to Vcc?
Please let me get your answer.

Regards,
Nicky

Nicky,

We'll double check the design of the IC to verify whether the statement in the datasheet is correct. I should be able to get back to you tomorrow.

Max

Nicky,

I have confirmed that the datasheet is in error. The two VCC pins are not tied together internally, so each one needs to be connected to the PCB. I will work to update the datasheet to correct this immediately. It may take a couple of weeks before the updates are published to the web. Thank you for bringing this to our attention so that we can correct our documentation.

Max