Buck Converter With Integrated LDO Saves Power

By integrating low on-resistance 10A power MOSFETs, a bootstrap switch, and a programmable Low-Dropout (LDO) regulator, all in a 5mm x 5mm MLPQ-32 package, the Semtech SC417 standalone synchronous buck power supply prioritises efficient use of energy and board space.

The SC417 is flexible for use in a broad range of applications, with an input voltage range from 3V to 28V and LDO output voltage adjustable from 0.75V to 5.25V using external resistors. The LDO can supply the bias voltage for the switching controller, allowing the device to be operated from a single supply rail.

With a programmable operating frequency from 200kHz to 1MHz, the SC417 helps designers to optimise operating efficiency as well as overall footprint through selection of external components. In addition, the buck controller uses pseudo fixed-frequency adaptive on-time control, which allows fast transient response and enables the use of smaller output capacitors. In addition to ceramic capacitors, standard capacitor technologies such as electrolytic or special polymer types can be used, for cost savings in price-sensitive applications.

Separate Enable inputs for the switching regulator and LDO support flexible power management. There is also a smart power-save feature, as well as soft-start and soft-shutdown functions, over-current and over-voltage protection, and cycle-by-cycle current limit.

 

FEATURES 150mA LDO 1% tolerance internal voltage reference Support for single-cell or multi-cell battery systems Power-good output

APPLICATIONS Personal computers and servers Networking and telecommunication equipment Printers Embedded applications Power-supply modules Point-of-load power supplies

 

 

Semtech / SC417