Thanks for providing the spice model of both ADA4433-1 and the ADA4830(-1).
I'm trying to design a DC coupled differential transmission system using the ADA4433-1 and the ADA4830.
The overall gain from input (ADA4433-1) to output (ADA4830) should ideally be 1.It is intended for composite video with a voltage range from 0 to 1V.
I tried to make this truly DC coupled by setting both -In of the ADA4433-1 and the Vref in of the ADA4830-1 to 0.5V.
The line is very short and only the drive resistors of 37.5Ohms are fitted. R2 is omitted in order to not lose signal amplitude.
In general, the simulated circuit works well. However, the output saturates just below 0.1V with a 150Ohm load to GND and a 3.3V supply.According to the datasheet, it should rather be 0.01V (Output Voltage Swing 0.01V to 3.08V @ 3.3V supply)
Any chance this combination of ADA4433-1 and the ADA4830(-1) would work as intended?An alternative would be to use an additional amplifier at the ADA4830's output for proper level shifting, and potentially some gain. But we would be very happy to get away without this added circuitry.
The LTspice simulation .asc file is attached.
Thanks for having a look at this.Kind regards,Ra
Hi Ra,Let me check this on simulation and get back to you.Regards,Goz
Hi Ra,Your circuit will work just fine, upon investigating the footroom at the output of the ADA4830 SPICE was not modeled properly.We'll get this fixed.Best Regards,Goz