Vishay Siliconix Releases New Triple-Output Step-Down Controller IC

The new SiP12203 provides all the required control circuitry and protection features for two switching step-down power rails, and one linear power output, in a broad range of applications including DSP, ASIC, and FPGA power supplies and dual power supply microprocessor and DSP cores.

The synchronous buck architecture of the new SiP12203 allows voltages to be converted with efficiency as high as 94%. The device features an input voltage range of 4.5V to 18V, with two independent outputs offering adjustable voltages as low as 0.6V, and 180° out-of-phase operation for reduced EMI and RMS input current. The IC’s third output is a built-in LDO controller that controls a discrete p-channel MOSFET in linear mode for up to 1A output current.

The device reduces the number of required external components to simplify the design layout and lower solution costs. The device further reduces design costs by driving two lower-cost external n-channel MOSFETs per channel, instead of one n-channel and one p-channel device. The 500-kHz operating frequency of the SiP12203, which can be synchronized with an external source, enables the use of smaller passive components in converter designs.

The device incorporates several protection features, including an adjustable overvoltage protection circuit that monitors the output current by sensing the voltage drop across the lower MOSFET, protecting the dc-to-dc components from damage during output overload/short circuit conditions. The SiP12203 also includes independent enable, current limit, feedback compensation, and internal soft start functions for each output. A single power good (PG) signal is issued when soft start is complete on both PWM controllers and their outputs are regulating.

Other protection features include under voltage lockout and thermal shutdown circuitry that turns off the device if the junction temperature exceeds +150°C. Voltage feed- forward compensation simplifies loop compensation in a wide range of input voltages.

The SiP12203 is available in a lead (Pb)-free MLP55-28 (QFN) package and is specified to operate over the junction temperature range of -40°C to +125°C.