THS3470: 10 MHz Square Wave to Sine Wave Conversion on 50 Ω Load

elhanan shifman

Part Number: THS3470
Other Parts Discussed in Thread: ISOM8710, ISO7710

Tool/software:

I have a 3.3 V, 10 MHz square wave output from my in-circuit FPGA.
I need to convert this signal into a sine wave, isolate it from my digital ground, and transmit it through a coaxial cable. The external load at the receiving end is 50 Ω.

To achieve this, I need a high-speed operational amplifier with approximately 100 MHz bandwidth, capable of generating around 6 V peak-to-peak into a 50 Ω load.
The amplifier should support a second-order filter design to convert the square wave into a sine wave.

Please help me find a suitable operational amplifier and a 10 MHz square wave isolator.

4 months ago

0 Vikas Jeevannavar 4 months ago

TI__Expert 3015 points

Hi elhanan shifman,

The conversion from 10MHz square wave to sine wave can be carried out with an amplifier which has high load driving capability of 6Vpk-pk and 50ohm load. It needs a large signal bandwidth > 10MHz, slew rate > 200V/us, support VCCA >6V and gain of +2. I would recommend OPA820 or LMH6654 for 2nd order LPF filtering. isolator suggestion will be provided by my colleague shortly.

Thanks

Vikas J

0 Varun Kumar 4 months ago in reply to Vikas Jeevannavar

TI__Expert 7675 points

Hi elhanan,

For the Galvanic Isolation between FPGA and the amplifier, I have following suggestions:

If the requirement is strictly opto input (INPUT Diode Current) ,then the best solution would be ISOM8710 (Max 5V Operation)
If the requirement is voltage input. then you can chose single channel Digital Isolator like ISO7710.

Regards
Varun

0 Vikas Jeevannavar 3 months ago in reply to Vikas Jeevannavar

TI__Expert 3015 points

Hi elhanan shifman,

It's been many days since this thread was created, and suggestions provided. Please let us know if you need further assistance or if the issue is resolved.

Thanks

Vikas J

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THS3470: 10 MHz Square Wave to Sine Wave Conversion on 50 Ω Load

Amplifiers

Amplifiers forum

THS3470: 10 MHz Square Wave to Sine Wave Conversion on 50 Ω Load

THS3470: 10 MHz Square Wave to Sine Wave Conversion on 50 Ω Load