Step-down supply reduces switching noise by 99 percent

April 04, 2012 // By Paul Buckley
Texas Instruments Incorporated (TI) has introduced a new class of voltage regulators designed to deliver the industry’s lowest-noise 1-A switching power supply without sacrificing efficiency and power performance.

The TPS54120, the first in the company’s family of QuietSupply regulators, reduces switching noise by up to 99 percent, compared to other power conversion devices, and helps maximize the performance of precision data converters and amplifiers and sensitive clock distribution circuits used in applications, such as telecommunications, test equipment, and high-end audio and video equipment.

The TPS54120 offers 99-percent noise reduction: 9 µVRMS at 100 Hz to 100 kHz, and 17 µVRMS at 100 Hz to 1 MHz.

The device features a high power supply rejection ratio (PSRR) of 83 db at 10 kHz, 70 dB at 100 kHz and is synchronizable to an external clock from 200 kHz to 1.2 MHz.  The TPS54120 has a wide input voltage range of 4.5 V to 17 V, adjustable output of 0.8 V to 6.0 V.

The TPS54120 is available in volume now from TI and its authorized distributors in a thermally enhanced 4-mm x 4-mm, 20-pin QFN or TSSOP package, and has a suggested resale price of $1.95 each in 1,000-unit quantities. The easy-to-use TPS54120EVM-103 contains all of the external components required for a low noise, 1-A solution with internal thermal and current limit shutdowns, power good output monitor, tracking and enabling/disabling circuitry.