Is it possible to use the OPA695 as a 110MHz signal output buffer?

kerb huang

Intellectual 690 points

Other Parts Discussed in Thread: OPA695, BUF602, LMH5401, LMH3401

Hello,

The output signal specification:

amplitude: -2.2V ~ +2.2V; Frequency: DC~110MHz; Output gain is around 13dB and flatness is within 0.2dB.

we want to use OPA695 as output buffer. is it possible?

Thank you!

over 9 years ago

0 Samir Cherian over 9 years ago

TI__Genius 12631 points

Hello kerb,

For small signals (100mVpp) that is certainly possible however the large signal BW is around 310MHz so you would be hard-pressed to get 0.2dB flatness with large signals and up to 110MHz.

The BUF602 will be able to get you a lot closer to your desired spec.

-Samir

0 kerb huang over 9 years ago in reply to Samir Cherian

Intellectual 690 points

Hi Samir,

BUF602 is unity-gain? it cann't amplify input signal.

Thank you,
kerb

0 Samir Cherian over 9 years ago in reply to kerb huang

TI__Genius 12631 points

Hello Kerb,
Sorry I missed the 13dB gain the first time. I just ran a quick TINA simulation and it looks like there is 0.42dB of attenuation for a 14dB, 4.4V output signal. If I split the design into 2 stages then there is 0.3dB flatness. Its the 4.4Vpp (peak to peak) output swing that is the bottleneck. We need an amplifier with around 1GHz of small signal bandwidth and > 7000 slew rate.

We have some amplifiers like the LMH3401 and LMH5401 that can do this but those are fully differential amplifiers. I cannot find a suitable amplifier that meets your 0.2dB requirement.

-Samir

0 kerb huang over 9 years ago in reply to Samir Cherian

Intellectual 690 points

thank you!

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Is it possible to use the OPA695 as a 110MHz signal output buffer?