LM2904B: How to change the differential amplifier gain?

Yong_Ju Kim

Part Number: LM2904B
Other Parts Discussed in Thread: LM2904, TLV9002, LM358LV, LM321LV, TLV9001

Hello.

I am designing a differential amplifier using LM2904.

I would like to increase the gain of my current differential amplifier, but it does not increase as much as the theoretical value, so I am asking for help.

Below is the circuit I use, the theoretical output is 2.63V, but the actual output is 1.97V.

Can you tell me why the output is different?

9 months ago

0 Clemens Ladisch 9 months ago

Guru 276360 points

The LM2904 does not have rail-to-rail inputs or outputs. With a 3.3 V supply, it is not guaranteed to handle voltages above 1.3 V.

The LM358LV/LM321LV would be able to handle up to 2.3 V. The TLV9002/TLV9001 has rail-to-rail I/Os.

0 Caro Walter 9 months ago in reply to Clemens Ladisch

TI__Mastermind 19057 points

Hello,

Please also reference the pre-built simulation circuitry in the following application note: Difference amplifier (subtractor) circuit

All the best,
Carolina

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LM2904B: How to change the differential amplifier gain?