Question: The MAX1737 a Synchronous Buck Converter in the schematic of the Evaluation Kit there is an additional diode in parallel to the Low Side Switch (MOSFET) but in the datasheet's typical application, there is none and no mention about this. Is there any information as to why the diode was added?
Answer: The Diode parallel to the low side switch of a Synchronous Rectifier helps in improving further the circuit efficiency. During switching transition there is a dead time, this is the time the Diode will conduct and instead of allowing the reverse current to flow in the low side switch body diode which is lossy. This is optional in the design but if there is an efficiency target, one might want to explore adding this diode. Here is an article to understand the theory of operation: Synchronous Rectification Aids Low-Voltage Power Supplies | Analog Devices.