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Forum Post: THS7530 Model & TINA Reference Circuit

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The THS7530 TINA Reference Circuit works as shown in the schematic on _/-2.5V supplies but there are serious problems with that macromodel as well as the reference circuit presentation:

1. The unlabeled pin is ? Who knows what it might be-- the symbol offers no clue. Looking into the model and at what is connected to this pin in the schematic reveals that it is probably the +gain control pin. The -gain control pin is apparently referenced to ground? Vs-? Who knows-- the text on the page offers no clue.

2. Has anyone looked at the voltage on the input pins with the DC Analysis test probe? Try it-- you get -4.8V on each input. Obviously something is wrong here. The model looks suspect.

3. Try connecting the THS7530 in the single supply circuits shown in the data sheet. The amplifier stops working-- instead of the output Vocm being pulled up to mid-supply as the data sheet and EVM manual says, the outputs go to a few hundred microvolts negative! Did anyone ever verify that this model actually worked?

4. The THS7530 macromodel offers no clue that it does not model the +Vcl or -Vcl functions. There is nothing regarding the modeling of other parameters that are vital for a high speed VGA-- noise, slew rate, settling time, etc.

Frankly, it is a shame that such a good device is being treated in this shabby manner. This amplifier deserves to have a reliable, accurate macromodel rather than this minimal-effort, half-a**ed offering.

I'm interested in hearing TI's excuse for not providing (again) a decent macromodel for their amplifiers.


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