•  
• EDN Europe MAGAZINE
•  
• Free SUBSCRIPTION
• Subscription Renewal
• View Media Kit

• EDN
• EDN Australia
• EDN Asia
• EDN China
• EDN Japan

D/A converter shapes sound for small speakers

 

Wolfson Microelectronics’ WM9081 is a single-chip mono DAC and speaker amplifier that the company designed to deliver optimum SPLs (sound-pressure levels) and maximum intelligibility from low-cost speakers, such as those used in portable navigation devices, mobile handsets, digital radios and conference speakerphones. The IC has a high-efficiency 2.6W speaker amplifier that can operate either in class AB or class D, a dynamic-range controller, and a ReTune Mobile 5-band parametric equaliser. SNR (signal-to-noise ratio) is 92dB in class D mode, and THD+N (total harmonic distortion plus noise) is 1% at 2.4W output power into a 4Ω speaker load. Relative to a typical two-chip solution, the 9081 uses 30% less board area and costs 20% less in bill-of-materials, Wolfson says.

The integrated ReTune Mobile equaliser has fully programmable coeffi cients allowing the user to defi ne speaker-frequencyresponse compensation and music profiles. Programmable dynamic-range control boosts low-level signals to maximise volume for improved intelligibility. The chip comes in a 28-pin COL QFN package; an evaluation system includes a board, schematics, a Linux driver and a downloadable software GUI, which allows the developer to make real-time modifi cations to an interactive version of the register map and modify the device confi guration whilst developing software settings.

Wolfson Microelectronics, www.wolfsonmicro.com.