LMH5401: Noise Figure vs Gain Settings data support

Jeho Choi

Prodigy 20 points

Part Number: LMH5401
Other Parts Discussed in Thread: LMH6401

Hello, experts.

I need the Noise figure vs Gain Settings data for LMH5401.

In case of LMH6401, The data plot supported but LMH5401 doesn't.

LMH5401 Setting is here, TA = 25°C, VS = 5 V, VCM = 0 V, RL = 200-Ω differential.

Thanks,

Jeho.

over 1 year ago

0 Venkat Devineni over 1 year ago

TI__Prodigy 220 points

Hi Jeho,

Thanks for your question.

LMH6401:

DC to 4.5 GHz, Fully-Differential, Digital Variable-Gain Amplifier - the gain can be varied digitally

Whereas LMH5401:

8-GHz, Low-Noise, Low-Power, Fully-Differential Amplifier - single gain (setting) amplifier

Please let us know if you have any other questions

- Venkat

0 Jeho Choi over 1 year ago in reply to Venkat Devineni

Prodigy 20 points

Hi Venkat.

Thank you for reply.

You wrote that LMH5401 is single gain fully differential amplifier. Does it mean that if the LMH5401 amplified with resistor, the noise figure will be the same?

Regards,

Jeho.

0 Venkat Devineni over 1 year ago in reply to Jeho Choi

TI__Prodigy 220 points

Hi Jeho,

Can you please let us know the position of the resistor you're planning to place?

- Venkat

0 Jeho Choi over 1 year ago in reply to Venkat Devineni

Prodigy 20 points

Hi Venkat.

The below is the circuit I use. I adjust R10 and R15 to vary the gain about 4dB to 10dB.

R10 and R15 will be changed according to the gain.

Best,

Jeho.

0 Venkat Devineni over 1 year ago in reply to Jeho Choi

TI__Prodigy 220 points

Hi Jeho,

Thanks for the detailed explanation. Let me get back to you soon.

- Venkat

+1 Venkat Devineni over 1 year ago in reply to Venkat Devineni

TI__Prodigy 220 points

Hi Jeho,

I think you'll find this helpful. https://www.ti.com/lit/an/snoa506a/snoa506a.pdf?ts=1663361446893&ref_url=https%253A%252F%252Fwww.google.com%252F

The long story short is yes it will vary, but not likely by a lot because Rf isn't usually a major contributor to the total noise.

- Venkat

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LMH5401: Noise Figure vs Gain Settings data support