Application Note : DCDC Converters (Switching Regulators)
Ricoh's step-down DCDC converters use diode rectifier and synchronous rectifier.
The diode rectifier type uses a schottky diode and the synchronous rectifier type uses a MOS transistor in the low-side switches.
The high-side and low-side MOS transistors are built in most of the Ricoh's DCDC converters except for the R1242, which uses synchronous rectifier and an external low-side MOS transistor.
R1240 (Diode Rectifier Type)
RP500 (Synchronous Rectifier Type)