Feedforward capacitor

The feedforward capacitor Cv,v, shown in Figure 8-7 has a voltage across it in steady state. When you short the output, the feedforward capacitor cannot... 

Figure 8-7 How to Damage a Switcher with a Feedforward Capacitor CFF...

Incidentally, don t blindly add a bypass capacitor in parallel with the (upper) feedback resistor, as suggested. That feedforward capacitor introduces another zero in the loop and can cause the system to go unstable. You should realize that this family of devices has a full-blown internal Type 3 compensation, so it even has an internal zero to emulate an external ESR zero. That is why this family is supposed to be able to handle ceramic capacitors at the output. If you introduce yet another zero (via the feedforward capacitor as suggested), you could have one too many zeros. And ultimately, your design could be one, too (a zero). 

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