I am reading the datasheet for an ADC. There is no reference as to what to do with unused pins.

I am willing to put some pull-up resistors but..

What would you do?

  • 1
    \$\begingroup\$ I'd ask TI for clarification. \$\endgroup\$ Mar 16, 2018 at 11:38
  • \$\begingroup\$ What pins have you utilized so far? Please show your schematic. \$\endgroup\$
    – AlmostDone
    Mar 16, 2018 at 11:39
  • 1
    \$\begingroup\$ Have you looked through the application notes? ti.com/product/TLV320AIC23B-Q1/technicaldocuments \$\endgroup\$ Mar 16, 2018 at 12:26
  • 2
    \$\begingroup\$ As a practical point, pull up (or down) via a resistor (non-critical, 1k or 10k usually OK) rather than directly to +V/0V. Makes overriding that choice later easy if you need to. \$\endgroup\$
    – user16324
    Mar 16, 2018 at 13:29

1 Answer 1


First, read the data sheet and the application notes. Carefully.

Generally any unused outputs can stay unconnected. If an apparently unused output needs to stay connected to some source of bias for proper operation of the rest of the chip, then the data sheet will tell you.

Generally all digital inputs need to be connected to a valid logic level to avoid excess supply current, even if you won't be using the function it's driving. If an input has an internal circuit to hold it at a valid level, then the data sheet will tell you that it can be left open.

Generally any unused analogue inputs should be kept within their valid voltage range, and quiet. Study the data sheet for each input to see what the valid range is, whether it will stay within that if left unconnected, and whether power consumption is dependent on its voltage. Ground is often OK.

In professional equipment, unused inputs are often taken to specific voltages through a series resistor. This allows the input to be probed during test, which allows standard test programs to be used. This is not usually an issue for hobby designers.

  • \$\begingroup\$ Thanks Neil, I actually read it, then tried to find for the words "unused" and "floating", in case I missed something, but nothing came out. I will learn that general knowledge ASAP. Thanks a lot \$\endgroup\$
    – Kroma
    Mar 16, 2018 at 14:51
  • \$\begingroup\$ @Kroma look for 'open', and 'nc' for 'no connect' as well. I'm sure there are more synonyms, be imaginative. \$\endgroup\$
    – Neil_UK
    Mar 16, 2018 at 14:58

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