In this case, the tracking resistors can be determined based on Equation 5: Rtrkb 0.8 VOUT 2 V 0.8 V u Rtrkt (5) and to ensure proper overdrive of the SS pin: VOUT 2 0.8 u VOUT1 (6) For the example case of VOUT1 = 5 V and VOUT2 = 2.5 V, with Rtrkt set to 33 kΩ...
Ideally the input clock must overdrive the threshold by a factor of 2, so direct drive from 3.3-V logic through a 1.5- kΩ Thevenin source resistance is recommended. Applying a sustained logic 1 corresponds to zero Hz PWM frequency and will cause the module to stop switching. 7.3.2 ...