Class G Speaker Amp Sheds The Inductor April 18, 2007
Deemed a first, the MAX9730 2.4W, single-supply, mono Class G speaker amplifier eliminates the boost converter and large inductor common to Class AB or Class D amps while achieving twice the output power. The amp delivers up to 500 mA over a 2.7V to 5.5V supply voltage, guaranteeing up to 2.4W into an 8Ω load from a 3.3V supply. It also promises to extend battery life via a proprietary output stage that reportedly provides efficiency levels greater than Class AB devices without the EMI penalties common to Class D amps. Other features include short-circuit and thermal-overload protection, click-and-pop suppression, shutdown control, soft-start circuitry, and an operational temperature range from -40°C to +85°C. Available in 20-bump, 2 mm x 2.5 mm lead-free UCSP and 28-pin, 4 mm x 4 mm TQFN packages, prices start at $0.80 each/1,000. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.
