The TPS54719 uses a transconductance amplifier for the error amplifier and readily supports two of the commonly used frequency compensation circuits. The compensation circuits are shown in Figure 7-11. The Type 2 circuits are most likely implemented in high bandwidth power supply designs using low-ESR output capacitors. In Type 2A, one additional high frequency pole is added to attenuate high frequency noise.

Figure 7-11 Types Of Frequency Compensation

The design guidelines for TPS54719 loop compensation are as follows:

1. The modulator pole, fpmod, and the esr zero, fz1, must be calculated using Equation 14 and Equation 15. Derating the output capacitor (C_OUT) can be needed if the output voltage is a high percentage of the capacitor rating. Use the capacitor manufacturer information to derate the capacitor value. Use Equation 16 and Equation 17 to estimate a starting point for the crossover frequency, fc. Equation 16 is the geometric mean of the modulator pole and the esr zero and Equation 17 is the mean of modulator pole and the switching frequency. Use the lower value of Equation 16 or Equation 17 as the maximum crossover frequency.
   Equation 14.
   Equation 15.
   Equation 16.
   Equation 17.
2. R3 can be determined by
   Equation 18.

   where:

   • gm_ea is the amplifier gain (250 μA/V)
   • gm_ps is the power stage gain (25 A/V)
3. Place a compensation zero at the dominant pole . C1 can be determined by
   Equation 19.
4. C2 is optional. It can be used to cancel the zero from the ESR of Co.
   Equation 20.