We were looking at an amplifier/booster to complement our current lab amplifiers and will be able to drive 20 Vpp into 50 Ω. We looked at doing a design using the TI THS3091, which has a ±250 mA capability and frequency response over 200 MHz. This will meet the 20 Vpp requirement perfectly when operating of a ±15 V supply.
We happen to see a module **broken link removed** that seemed to incorporate this part at a very good price. There are numerous sellers offering this module, and we even found it on Alibaba.
I am very aware of fake/cloned parts used by manufacturers, but decided to get the module as the part can always be replaced with a proper Texas Instruments part.
Well, a few days ago, the module arrived from China, and I performed some basic tests on it in the lab.
1) It failed miserably to drive a 50 Ω load. While the open-circuit voltage could reach in excess of 20 Vpp, the loaded voltage with minimal distortion, was only about 5.6 Vpp!
2) Next I performed a bandwidth test and found it to be about 40 MHz, instead of the claimed 210 MHz.
So I messaged the seller, confronting him with all the test results. I received a reply that it was passed on to the engineer. It will be very interesting to hear his reply, since they actually refer to the TI datasheet specs on their listing.