**Part Number:**TLV9062

**Other Parts Discussed in Thread:**CSD17483F4, TIDA-010014, OPA365

**Tool/software:** WEBENCH® Design Tools

Hi there,

I have been checking the Linear Led driver from your reference design TIDA-010014 that uses the TLV9062 and a CSD17483F4 MOSFET

In the first AC Small Signal Stability Simulation you obtain a Phase Margin of 88.92 at a cross frequency of 3.95MEG using the following circuit

I understand the compensation network and the fact that L1 and C2 are there for DC and AC analysis and will act as a short or as an open circuit,however, I wonder why the designer used a DC voltage of 70mV (V2 in the image) injected into the non inverting input (+) of the OpAmp?

For this kind of stability test we are supposed to tied to ground the non inverting input (+), am I right? adding this DC supply will change the behavior of the Open Loop Gain, 1/B and in general the Phase Margin of the circuit, and lead to a wrong stability analysis.

If we tied to ground the non inverting input (+) in the TINA SPICE file that you provided for this design we obtain totally different response with a very different Phase Margin for sure, as shown below:

In general, any other value smaller or larger than 70mV will completely change the response.

Am I getting lost somewhere ?

Any help will be appreciated.

Thanks