MAX3232E: If unused channel of TX and RX needed external pull up and pull down for or it has internal pull up and pull down for it

Rony Kuruvilla

Part Number: MAX3232E

Tool/software:

If unused channel of TX and RX needed external pull up and pull down for or it has internal pull up and pull down for it. Or it OK to use it as no connect for the unused pin

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10 months ago

0 Clemens Ladisch 10 months ago

Guru 316690 points

Unused DIN pins must be connected to V_CC or GND. Unused DOUT/RIN/ROUT pins should be left open.

0 Rony Kuruvilla 10 months ago in reply to Clemens Ladisch

Prodigy 80 points

Hi Clemens
Din1 ,Rin1 can be left open or need to be pulled up with resistor or pulled down with resistor
Is there amy issue if left open Din1, Rin1, Dout 1, Rout1
when i checked the data sheet Rin1 has internal pull down of 5K .is this the same case of DIN1

0 Clemens Ladisch 10 months ago in reply to Rony Kuruvilla

Guru 316690 points

No, DIN1 does not have an internal pull-down/-up.

0 Ethan Sempsrott 10 months ago

TI__Genius 13422 points

Hi Rony,

The unused RIN and DIN pins cannot be floating. It is best practice to tie RIN and DIN to ground with a 3 to 5K resistor if not in use. DOUT and ROUT pins can be left floating if not in use.

Regards,

Ethan

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MAX3232E: If unused channel of TX and RX needed external pull up and pull down for or it has internal pull up and pull down for it