LM393: What's the different between LM393PW and LM393PWR?

Jim Tsai

Expert 4470 points

Part Number: LM393
Other Parts Discussed in Thread: , TLV9022

Hi,

As subject, what's the different?

Can these 2 devices share the same design (the same BOM and circuit)?

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 287110 points

PW devices are packaged in a tube, PWR, on a reel. The chips are identical.

0 Chi Nguyen1 over 1 year ago in reply to Clemens Ladisch

TI__Genius 11701 points

Thank you Clemens.

Hope that answers your question, Jim.

0 Jim Tsai over 1 year ago in reply to Chi Nguyen1

TI__Expert 4470 points

Hi Clement,

Could you please help to double check below circuit?

Customer report some RMA issue, no output on pin1 1 OUT.

The only change is they use LM393PWR instead of LM393PW.

0 Clemens Ladisch over 1 year ago in reply to Jim Tsai

Guru 287110 points

The LM393 does not have rail-to-rail inputs; it requires a headroom of 2 V to the positive supply. So with a 3.3 V supply, the input signals would have to be below 1.3 V.

Use the LM393LV or TLV9022 instead.

0 Jim Tsai over 1 year ago in reply to Clemens Ladisch

TI__Expert 4470 points

Hi Clemens,

what’ll happen if the input signal higher than 1.3V? no output response when IN+ higher than IN-?

Customer need to adjust input signal divider bottom resister to make sure all the voltage go through input pin are below 1.3, right?

0 Clemens Ladisch over 1 year ago in reply to Jim Tsai

Guru 287110 points

Above 1.3 V, correct operation is not guaranteed. (Actually, only one input above 1.3 V will work, but with reduced performance.)

You could adjust the voltage dividers. But pin 2 does not have a bottom resistor; it might be easier to use the LM393LV or TLV9022.

0 Jim Tsai over 1 year ago in reply to Clemens Ladisch

TI__Expert 4470 points

Hi Clemens,

for the headroom 2V discretion or spec, can I find in datasheet?

0 Clemens Ladisch over 1 year ago in reply to Jim Tsai

Guru 287110 points

0 kai klaas69 over 1 year ago in reply to Jim Tsai

Guru 140200 points

Hi Jim,

also, section 8.2.2.1 of datasheet contains useful information.

Kai

0 Paul Grohe over 1 year ago in reply to Jim Tsai

TI__Guru 54036 points

Hello Jim,

Please see the LM393 family application note. This should answer your questions.

Application Design Guidelines for LM339, LM393, TL331 Family Comparators

As stated, we recommend keeping the input voltage below Vcc-2V, or using the LM393LV.

0 Jim Tsai over 1 year ago in reply to Paul Grohe

TI__Expert 4470 points

Hi all,

Appreciate all of your support, I will communicate with customer and help them to solve the issue.

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LM393: What's the different between LM393PW and LM393PWR?