TLE2301: Compensation Calculations

Hi Richard,

We do not have any details about the TLE2301 internal design beyond the simplified schematic shown in the datasheet. It doesn't provide us the information that would be needed to establish how the compensation values are computed. Therefore, some bench measurements may provide the quickest way forward.

My suggestion is the start with CF1 = 15 pF and CF2 = 39 PF as shown in datasheet Figures 24 and 26, even though the particular circuit  they are working on may be different than those shown. Run a small-signal square-wave input such that a 1 kHz, 20 mVpk waveform is observed at the output. Make sure the output is driving the expected load. Look at the output waveform and specifically the overshoot on the output square-wave. Use the transient overshoot information in the Analog Engineer's Pocket Reference, Figures 34 and 35, to determine the phase margin. If the output square-wave is over-damped, rounded rising edges instead of overshoot on rising edges, then the TLE2031 may be overcompensated. Then try reducing CF1 and CF2 proportionately if more bandwidth, or faster response time is needed.

Here's the path to the pocket reference: https://www.ti.com/seclit/sl/slyw038b/slyw038b.pdf

It is a good idea to add a dc offset to the input signal such that the output dc level can be moved through the zero-cross point, and beyond. Look to see that the small-signal square-wave remains about the same as the dc offset causes the output to move from positive, through zero, and then negative. If the overshoot becomes excessive at any point compensate the amplifier to bring it within an acceptable range at that point.

Regards, Thomas

Precision Amplifiers Applications Engineering

Hi Richard,

I would also, like Thomas, use a small signal square wave and optimize CF1 and CF2 for acceptable ringing at output of TLE2301.
Datasheet mentiones a phase margin at unity gain of only 30°/35° and figure 19, e.g., shows a considerable ringing. Not nice. So, it IS neccessary to adjust CF1 and CF2 to your application. And don't omit Rs!

If it helps, I know from an application where the TLE2301 is used as unity gain follower (gain=+1) with CF1=47p, CF2=39p and Rs=4R7.

Kai