Attention to Internet Explorer users: ROHM website does not recommend browsing in IE 11. Please use latest browser to ensure the best performance on ROHM website.
A MOSFET probably could not be destroyed as the result of a mistaken selection of a bootstrap capacitor. If the capacitance is too great, adequate charging is not possible, so that Vgs would be insufficient; if the capacitance is too small, the electric charge that charges the capacitor would be inadequate, so that Vgs would again be insufficient. As a result, turn-on of the high-side MOSFET would be delayed, and depending on the extent to which Vgs was inadequate, it might not be possible to turn the MOSFET on at all. As a result, it is likely that the output voltage would drop, or that operation would stop.