THS4513: AC coupled Single Ended to differential converter

Part Number: THS4513


I'm trying to simulate a circuit using a THS3095 followinf by a THS4513 and I have some questions.

First stage is a unity gain non inverter THS3095 to buffer my signal. After this stage, signal is good but the common mode of my signal is not the common mode of the second stage, based on THS4513.

The aim of the second stage is to convert the single ended signla into differential one in order to drive an ADC.

I prefer to avoid of setting the common mode on the output of the first stage because high and low levels of my signal can vary so, I tried to AC coupled the two stages but it's not working.

It works correctly if I DC coupled the two stage and set the common mode of the signal at the output of the THS3095 at the same value than the common mode of the THS4513.

I just want the same signal as the output of THS3095 but in differential mode 0V centered.

Could anybody explain me what is wrong, please? Regarding the Datasheet, it seems to be working.


Matthieu Baque

2 Replies

  • Hi Matthieu,

    I built your circuit in TINA-TI and simulated with AC coupling. I didn't see any issues using the AC coupling between the devices as expected. You can download the TINA schematic from here.

    What problem are you experiencing with the AC coupling compared to the DC coupling in your simulation?

    Jacob Freet 
    High Speed Amplifiers

  • In reply to Jacob%20Freet:

    Hi Jacob,

    Indeed, the circuit works well in TinaTI. By comparing the two circuit, I see a difference on the bias point calculation.

    I can correct my issue adding some initial conditions in Pspice.


    Matthieu Baque