LM2903B: LM2903B

Kunal Pathak

Part Number: LM2903B
Other Parts Discussed in Thread: TLV1704, LM393B, LM393LV, TLV7022

Hi,

We are using the TLV1704 previously but due to some reason (pitch, etc.) we switched to LM2903B.

1. We understand that TLV1704 and LM2903BIDR both comparators are same. Wanted your confirmation on this.

2. Now, with LM2903B comparator we are facing issue in simulation. The comparator is not working properly (it's not switching). Have used the latest model available in TI website which is of LM393B.

So, is it happening due to model issue or other things? Please confirm.

Have attached the simulation circuit and results snap.

The reference is set for 3.26V, but comparator is not detecting it. Please give your suggestions.

Regards,

Kunal

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 243980 points

The LM2903B does not have rail-to-rail inputs; you have to leave a headroom of 2 V to the positive rail.

There are no dual open-collector rail-to-rail comparators in the TSSOP package.

How many comparators do you need? What package sizes can you use?

0 Paul Grohe over 3 years ago

TI__Mastermind 49966 points

Hello Kunal,

As Clemens stated, the LM2903B is not a rail-to-rail input. The maximum input voltage is Vcc-2V, or 3V on a 5V supply.

The model is designed to fail if the input range is violated.

I would suggest trying the new LM393LV or TLV7022, which has R-R inputs.

0 Kunal Pathak over 3 years ago in reply to Paul Grohe

Intellectual 375 points

Hi Clemens/ Paul,

Thank you for the response.

I tried using LM393LV but the spice model is not getting created for that. Below is the error message poping up,

So, can you resolve this or provide a spice model for LM393LV.

Regards,

Kunal

0 Joe Vanacore over 3 years ago in reply to Kunal Pathak

TI__Genius 10535 points

Hi Kunal,

I have attached the link to download the PSpice model for the LM393LV. Please let me know if you run into any issues.

Kind Regards,

Joe

0 Kunal Pathak over 3 years ago in reply to Joe Vanacore

Intellectual 375 points

Hi Joe,

The same issue is happening, the model is not getting created. Below is a snap of the error message.

I tried both .lib and .CIR files for creating model, but it's showing some error. Please resolve the issue.

Regards,

Kunal

0 Joe Vanacore over 3 years ago in reply to Kunal Pathak

TI__Genius 10535 points

Hi Kunal,

I will work on getting you a working LM393LV model by the end of business tomorrow 1/21.

Kind Regards,

Joe

0 Joe Vanacore over 3 years ago in reply to Joe Vanacore

TI__Genius 10535 points

Hi Kunal,

We are still working on fixing the model for the LM393LV. I will post it to this thread once it is fixed.

Regards,

Joe

0 Kunal Pathak over 3 years ago in reply to Joe Vanacore

Intellectual 375 points

Hi Joe,

Can you please provide the model ASAP.

Regards,

Kunal

0 Joe Vanacore over 3 years ago in reply to Kunal Pathak

TI__Genius 10535 points

Hi Kunal,

I apologize for the delay. Here is the revised LM393LV Tina schematic. We will be updating the model on the web shortly.

Let me know if you run into any issues.

Kind Regards,

Joe

LM393LV_REV.TSC

Amplifiers

Amplifiers forum

LM2903B: LM2903B