SLLA549 July 2021 TCAN4550 , TCAN4550-Q1 , TCAN4551-Q1

12 Recalculate Critical Transconductance and Gain Margin

If a series dampening resistor is used, the critical transconductance gm_crit and gain margin needs to be recalculated to ensure there is still enough gain margin to start and maintain oscillation.

Equation 33.

g m_{c r i t_w i t h_R d} = 4 \times (R_{l o a d} + R_{d}) \times ω^{2} \times {(C_{0} + C_{L})}^{2}

Equation 34.

{G a i n}_{m a r g i n_w i t h_R d} = \frac{g m}{g m_{c r i t_w i t h_R d}}