SNVA103B October   2005  – February 2022 LM2743

 

  1.   Trademarks
  2. 1Introduction
  3. 2Additional Footprints
  4. 3Guidelines for Additional Options
  5. 4Typical Application Circuit
  6. 5Performance Characteristics
    1. 5.1 Load Transient Response
    2. 5.2 Switch Node Voltage and Output Ripple Voltage
  7. 6PCB Layout Diagrams
  8. 7Revision History

2 Additional Footprints

A Schottky diode footprint (D1) is available in parallel to the low-side MOSFET. This component can improve efficiency, due to the lower forward drop than the low-side MOSFET body diode conducting during the anti-shoot–through period. Select a Schottky diode that maintains a forward drop around 0.4 V to 0.6 V at the maximum load current (consult the I-V curve). In addition, select the reverse breakdown voltage to have sufficient margin above the maximum input voltage.

Footprint C13 is available for a multilayer ceramic capacitor (MLCC) connected as close as possible to the source of the low-side MOSFET and drain of the high-side MOSFET. This will provide low supply impedance to the high speed switch currents, thus minimizing the input supply noise. For example; a MLCC is used (C13) in combination with aluminum electrolytic input filter capacitors, placed in designators C12 and C14, because MLCC has lower impedance than electrolytics. If MLCCs are used in designators C12 and C14, component C13 is not necessary.

The PCB is designed on two layers with 1-oz. copper on a 62-mil FR4 laminate.