More and more portable devices are incorporating Wi-Fi. You'll find it in digital cameras, personal digital assistants, and industrial wireless devices as well as in laptops. Power amplifiers for these applications must be able to meet the standard's extreme power output specifications, but they also should go easy on the power consumption.
Avago Technologies' MGA-412P8 highoutput linear power amplifier primarily targets the 802.11b/g wireless local-area network market. Yet it also can work in other 2.4-GHz applications, such as Bluetooth or industrial-scientific-medical (ISM) band designs.
According to Avago, the MGA-412P8 uses the company's unique enhancement-mode pseudomorphic high-electron mobility transistor (E-pHEMT) to create a multistage class A to class AB linear amplifier with the lowest power consumption available. With a 3.3-V supply, it provides 25.5 dB of gain with an output of +19 dBm in 802.11g orthogonal frequency-division multiplexing applications transmitting at 54 Mbits/s.
The error vector magnitude is only 3% at a current drain of 95 mA. Transmitting an 802.11b complementary code keying (CCK) signal at 11 Mbits/s, the MGA-412P8 supplies +23-dBm output with a current drain of 200 mA. Typical quiescent current is only 40 mA. The reverse isolation is better than 40 dB.
The device includes an integrated power-detector and special power-down functions. In shutdown mode, it draws only 5 µA at 3.3 V. Its 2- by 2- by 0.75-mm eightlead leadless plastic chip carrier package is aong the smallest available (see the figure). The device is lead-free, and the backside metalization provides excellent thermal dissipation.
The MGA-412P8 costs $0.73 in moderate volume.
Avago Technologies Inc.
www.avagotech.com