As described in Output Voltage Sensing, BW pin is multiplex for BMTL/BMTH ratio programming. The programming phase happens only once before startup. After that, the BMTL/BMTH ratio is then fixed, until system restarts after a fault or power recycle. The programming phase occurs right before soft start begins. It sources a constant current and measures the voltage on the pin. Depending on the measured pin voltage, different ratio of BMTL/BMTH is selected as listed in Table 2. The required BW equivalent resistance is listed in electrical characteristics section.
Other than selecting different BMTL/BMTH ratios, the option 5 also disables the LL/SS pin initial voltage program phase during startup, and the option 7 disables the burst mode.
|5||0.6 (LL/SS pin initial voltage programming disabled)|
|7||0.4 (Burst Mode Disabled)|