Low-noise LDOs for Hi-Fi circuits up to 1A

Rohm has introduced ‘high-fidelity’ power supply ICs aimed at audio devices requiring high-resolution audio play-back.

Above the quality of CD audio, it sees high-resolution audio sources typically playing back at “greater than 96kHz and 24bit”.

Called the BD372xx series, the regulators have a newly-developed fast error amp circuit and low-noise architecture.

“Multiple parameters that were shown to affect audio quality in the development and manufacturing processes were optimised via real-world listening tests, resulting in industry-leading performance in voltage stability, noise level, and power supply symmetry,” claimed the firm. “The result is a very clean power supply compared with conventional solutions, making it possible to achieve higher audio quality, including improved sound imaging and resolution.”

There are three versions:

BD37201NUX produces 1.0-4.5V at 500mA from 2.7-5.5V

Then a pair produce matching positive and negative rails

BD37210MUV: 1-15V at 1A from 3.0-16V
BD37215MUV: -1 to -15V at 1A from -3 to 16V

In each case, noise across 10Hz to 100kHz is under 6uVrms – see table for other parameters.

“BD37201NUX is ideal for low-voltage digital devices such as DACs and DSPs, while the positive BD37210MUV and negative BD37215MUV are optimised for analogue devices like sound processors and current-voltage conversion amps that operate using both positive and negative voltage supplies,” said Rohm.

Typical stand-by current is 5.8μA for the BD37210MUV.

Applications are foreseen in Hi-Fi audio systems, headphone amplifiers, portables, home audio and wireless speakers.