Contextual Info: User's Guide SNVA277B – October 2007 – Revised May 2013 AN-1691 LM20143 Evaluation Board 1 Introduction The LM20143 is a full featured buck switching regulator capable of driving up to 3A of load current. The switching frequency of the LM20143 can be varied from 500kHz to 1.5Mhz with an external resistor