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STMicro TSX339IQ4 Vcm, as drop-in for TI LM339LVRTE?

RescueBlues
Associate

I'm looking at this ST Micro part
   ST MICROELECTRONICS TSX339IQ4 --- power from 2.7V to 16V.
         But Vicm limitation of Vcc - 2V. At 3.3V-2V = 1.3V.
          But need Vcm at 2.5V., so 2.5V + 2V = 4.5V, so likely Vcc = 5V.

as an alternative source to this TI part:
    TEXAS INSTRUMENTS LM339LVRTE -- power from 1.65V to 5.5V. Vcm from 0 to Vcc.

I'd like to power the IC off of 3.3V and don't have a convenient source of 5V. And I *must* use a Vref of 2.5V given the other I/O requirements.

Unfortunately although the TI part will work at 3.3V with Vref of 2.5V (since its allows Vcm is 0-Vcc), the ST Micro part won't work that way. It's Vcm is limited to Vcc - 2V = 3.3V-2V = 1.3V, 1.2V *below* the required Vref of 2.5V. To allow the ST Micro part to work at 2.5V, it would require a Vcc of 2.5V+2V = 4.5V => 5V. Both the ST Micro & TI would be OK at Vcc=5V *but* I don't have a source of 5V on this design or way to distribute it to the *many* comparators used.

Any suggestions, or alternate parts that are footprint equivalent for ST Micro vs. TI vs. ???

3 REPLIES 3
Peter BENSCH
ST Employee

Welcome @RescueBlues, to the community!

If you are working with 3.3V and need low current consumption you could use the TS884 instead.

Hope it helps?

Good luck!
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

Thanks, good idea.

I was comparing the ST Micro TS884IQ4T to the TEXAS INSTRUMENTS LM339LVRTE. Similar specs, rail-to-rail Vicm, same QFN16 package. 

SOOOO Close, but...  I then noticed that the pinouts for the two are different (e.g. TI part has all their OUTs 1-4 on one side, but the ST Micro mixed INs & OUTs on two sides. Then a few diffs for VCC, GND, etc.). Too bad. I'd have to pick one xor the other and can't put the two on the same AML.

Peter BENSCH
ST Employee

If you can't or don't want to use the TS884IQ4T, I'm sorry and you have to use the other device, because STMicroelectronics has no alternative with this pin assignment in a QFN16.

Good luck!
/Peter

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.