LMH6554 as ADC Driver with 5V single supply for 60MHz IF AC coupled

Amit Jagtap

Other Parts Discussed in Thread: ADC16DV160, LMH6554, LMH6514, LMH6515

I am using LMH6554 to drive ADC16DV160 in AC coupled mode for the input signal of IF 60MHz, with -50dBm to 14dBm of Dynamic range.

I have biased LMH6554 with single supply 5V instead of Dual supply +/-2.5V.

I have done simulation in TINA. It looks fine.

Just want to confirm whether single supply operation for AC coupled application as mentioned above is suitable or not.

Thank you,

Amit

over 8 years ago

0 Loren Siebert 1 over 8 years ago

TI__Genius 13935 points

Hello Amit,

Your circuit is configured correctly. AC coupling gives a lot of flexibility in supply configuration.

You mentioned 14dBm as a maximum input level. In a 50 Ohm system 14dBm is 3.2Vpp. This circuit has a gain of 4. That will overdrive the ADC in strong signal conditions.

Do you have a variable gain stage ahead of the LMH6554? If not you may want to look at the LMH6515 or LMH6514. These amplifiers have variable gain and are designed for an AC coupled IF signal path.

Let me know if I can be of further assistance.

Regards,

Loren

0 Amit Jagtap over 8 years ago in reply to Loren Siebert 1

Intellectual 620 points

Hello Loren,

I have a unity Gain and a passive filter in front of LMH6554.

and input maximum is 2.2V not 3.2V...by mistake gave wrong input.

So, to conclude, I can bias opamp with single supply....pls confirm.

Thank you.

0 Loren Siebert 1 over 8 years ago in reply to Amit Jagtap

TI__Genius 13935 points

Hi Amit,

Yes, you can bias the op amp with a single supply. You will still want to verify that the maximum signal is not too large for your ADC.

Regards,
Loren

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LMH6554 as ADC Driver with 5V single supply for 60MHz IF AC coupled