TPS549B22: TPS549B22

grzegorz 

I would not recommend using the BP output to power an external circuitry, especially not one with 60mA expected loading current.

1) The BP internal LDO has a nominal current limit of 100mA.  The current needed to power the internal drivers plus the external 60mA may force the LDO into current limit.

2) The BP provides current for the internal drivers and experiences transients during the switch transitions, specially on the falling edge of switch when the low-side FET is turned on while the SW to BOOT capacitor is recharged through an internal diode.

3) While the TPS548B22 is designed to tolerate the noise on BP generated by the normal switching action, noise on BP induced by external loading can negatively affect the performance of teh TPS548B22, which uses the BP voltage to bias most of the internal analog functions.

4) The added loading on the BP pin will significantly increase the power dissipation in the TPS548B22.