TRS3232: Max3232 / TRS3232: single channel use

Daniel Ka

Intellectual 607 points

Part Number: TRS3232

Hi,

if only a single channel is used, how do you handle unused inputs? There are several options!

This answer suggests to pull DIN to VCC or GND.

e2e.ti.com/.../trs3232-how-to-handle-unused-pins

This answer suggest to leave DIN open (mentioning an internall pull down resistor).

e2e.ti.com/.../trs3232-single-channel-use

What is correct?

Thanks.
Dan

over 3 years ago

+1 Tyler Townsend over 3 years ago

TI__Mastermind 47828 points

Hi Dan,

I believe the top source is correct. You should pull DIN to VCC or GND according to section 9.2.2. of the datasheet:

ROUT, DOUT, and RIN can be left floating.

Regards,

Tyler

0 Clemens Ladisch over 3 years ago in reply to Tyler Townsend

Guru 317000 points

Additionally, the I_IH specification shows that the DIN inputs do not have internal pull-down resistors, and that the second answer linked above is wrong.

0 Daniel Ka over 3 years ago in reply to Clemens Ladisch

Intellectual 607 points

Thank you for the responses and for the official confirmation.

Then maybe the second answer linked above should be deleted "for correctness sake".

Best regards,
Dan

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TRS3232: Max3232 / TRS3232: single channel use