THS4532: About wrong output waveform.

Hello Jimmy,

Are you using an input voltage of 1V peak-to-peak sine wave, or a 1V amplitude (2V peak-to-peak) sine wave?  If you are swinging 1.84V from 1.5V, you would be swinging to the positive supply rail at 3.3V.

I would try a smaller waveform, 500mV amplitude (same as 1V peak-to-peak input waveform) and see if you get the appropriate amplitude.  Your output common mode voltage is set to 1.5V, which is the reference voltage for the two outputs to drive the AC output signal.

Best,

Alec

Hi Alec,

Green waveform is input signal. 0~1V offset is 0.5V

The Gain setting is 2.36, but the output is not as expected.

Hi Alec,

Customer changed the gain setting as 5.1 (1K and 5.1K)

Green is input around 0.5V Vp-p offset 0.25V

VCC is 3.3V.

but Vo(Yellow) output only 2Vp-p Gain around 4. Is it possible? 

Hello Jimmy,

I am going to test this in simulation for you. Can you provide the input signal which represents your project/application?  I will use your gain circuit and run some simulations to determine what appropriate operation would be for this circuit.

Best,

Alec

Hi Alec,

Gain setting is 2000R/865R =2.37

Input signal is 1Vp-p( 0V~1V)  offset 0.5V 

Hi team,

Could you update? thanks 

Hi team,

Could you update? thanks 

Hello Jimmy,

I am working on an update.  

Best,

Alec

Hi Alec,

Do you have an update? thanks 

Hello Jimmy,

What is the load on the outputs of the FDA?

Measuring or simulating an unloaded FDA could create variation or assumptions by the simulator.

For best results, I would benchmark the SPICE model by simulating under the datasheet conditions, such as in the electrical characteristics table or typical characteristics curves.

Best,

Alec

Hi team,

customer use the caulator, but seems output voltage is not as expected.

Does any setting not make sense? 

Hello Jimmy,

Could you have the customer try the FDA calculator at this link?

https://dev.ti.com/gallery/view/CircuitDesignStudio/Analog_Circuit_Design_Studio/ver/1.0.0/

We would appreciate any feedback.

Best,

Alec

Hi Alec,

Could you give me a setting that can support the design when Vin=1Vp-p offset=0.5V  and output is 2.33V( 0 to 2.33V). thanks 

Hello Jimmy,

Do you want the output centered around a DC bias of (2.33 / 2)V?  Or would you want the output centered around midsupply (1.65V) or the original VREF of 1.5V in the above schematics?

Best,

Alec

HI Alec,

Customer wants the original VREF of 1.5V in the above schematics.

Hello Jimmy,

Thank you, I will provide a circuit configuration to you this week.

Best,

Alec