I'm having a signal that starts at 0V and linearly increases to 2.4V as output and I would like to buffer it such that it cannot be influenced by resistive loads. The issue is that the only buffer circuit I've learned is the source follower (common drain amplifier) such that it takes as input (gate voltage) the output of my previous circuit. But as this signal starts at 0V, the gate voltage is not high enough compared to Vthreshold and then the transistor is not in saturation and the circuit does not work correctly.
As you can see on this simulation, there is a delay before it starts following (also the slopes are not the same).
And here is my source follower with L=350nm and W = 1000nm.
Could you help me solving my issue. Either by suggesting another buffer circuit for resistive load or by having a trick so that the source follower can work for input lower than Vth.