LM393B: Unused pins App note SNOAA35A

Renan Santos Adriano

Part Number: LM393B

Hello Team,

SNOAA35A shows unused pins connected to Vcc in section 5.1.2 figure 9, but connecting to Vcc violates the input voltage range (discussed in section 2.2), so how is it best practice to connect the unused pin to Vcc? Would it not be better to use a voltage divider to keep the input within the required input voltage range instead of pulling up to Vcc?
Also SNOAA35A figures 9 and 10 are identical in the app note. What am I missing here?

Regards,

Renan

over 3 years ago

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi Renan,

it does not harm provided only one input exceeds the positive common mode input voltage range. Please read section 8.2.2.1 of datasheet.

Kai

0 Chuck Sins over 3 years ago in reply to kai klaas69

TI__Mastermind 23425 points

Thanks Kai for the support.

Chuck

0 Paul Grohe over 3 years ago

TI__Mastermind 49946 points

Hello Renan,

There is a duplicate image inserted. There should only be Figure 9.

Ignore Figure 10, as it is the same graphic with a slightly different title.

This is on my to-fix list.

You can also ground one input and "Borrow" a steady reference voltage from one of the other channels.

You can also tie (through a resistor) to V+ as it will not cause damage and you are not using that channel, so minor shifts in specifications on that channel are not an issue. See section 2.5 for the "feature".

Amplifiers

Amplifiers forum

LM393B: Unused pins App note SNOAA35A