One-chip power supply packs four outputs in 25mm²

The MC34700, from Freescale Semiconductor, is a four-output power-supply IC featuring integrated power MOSFETs, 800kHz switching frequency and internal protection features to enable a compact multi-rail power supply with minimal external components.

In addition to saving board space, the MC34700 also saves designers from tasks including MOSFET selection, optimising switching frequency, and programming soft-start time.

The 5mm x 5mm QFN package integrates four step-down regulators consisting of two synchronous switching regulators, one non-synchronous switching regulator and one linear regulator. Each channel has a separate enable input for independant control and power-up sequencing.

The first channel operates from an input voltage of 9V to 18V and delivers 2.0V to 5.25V at 1.5A. Channels two and three can source up to 1.25A at 0.7V to 3.6V, operating from a 1.5V to 6V input. The linear regulator also has an input voltage range of 1.5V to 6V, and produces 0.7V to 3.6V at 400mA. Channels two and three can derive their input supplies from the output of channel one or from an external bias voltage. The fourth channel can derive its input supply from any output of channel one through to three, or from an external bias voltage.

 

FEATURES Internal soft-start function Voltage feed-forward on channel one ±1.5% output-voltage accuracy Cycle-by-cycle current limit Power-good output signal

APPLICATIONS Set-top boxes Cable modems Point-of-Sale (POS) terminals Laser printers Small appliances Telecom line cards

 

 

 

Development board KIT34700EPEVBE is available to members of the Future Board Club. To apply for the development board, and membership of the Board Club, go to www.my-boardclub.com/manf-offers.htm This offer is free and subject to qualification.

 

Freescale Semiconductor / MC34700