New Industry Products

Vishay Releases Triple-Output Step-Down Controller IC For One Linear & Two Synchronous Power Rails

October 15, 2008 by Jeff Shepard

Vishay Intertechnology, Inc. released a new high-performance triple-output step-down controller IC designed for efficient power conversion in set-top boxes, base stations, wall adapters, consumer electronics, and network intermediate bus dc input supplies. 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 4.5 to 18V, with two independent outputs offering adjustable voltages as low as 0.6 V, and 180-degree 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 company claims that the device reduces the number of required external components to simplify the design layout and lower solution costs. The device is said to further reduce 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 to +125°C.

Samples and production quantities of this new triple output step-down controller IC are available now, with lead times of 12 weeks for larger orders. Pricing for U.S. delivery in 10,000-piece quantities is $1.49.