WI-FI 802.11 technology is nearly ubiquitous. Yet new market segments are emerging, like Voice over Internet Protocol (VoIP) in Wi-Fi cell phones and hot-spot access points and PC cards for laptops. Each application has its own requirements. Three front-end modules in SiGe Semiconductor's RangeCharger power-amplifier line let designers optimize their Wi-Fi design to emphasize performance, battery life, or transmission range as required.
SiGe Semi's SE2521A40, SE2521A60, and SE2521A80 operate in the 2.4-GHz Industrial, Scientific, and Medical band and work with 802.11b/g. Each IC contains a linear power amplifier, a power detector, and a transmit-receive (T/R) antenna switch. The built-in filters and impedance matching circuits greatly reduce the need for external components and simplify design.
The SE2521A40 is designed for handsets. It has an output power of +18 dBm and an error vector magnitude (EVM) of less than 3%. With its low power consumption (less than 150 ma in 802.11g mode), designers can use it to put VoIP in a cell phone.
The SE2521A60 targets PC cards for laptops. It has an output power of +19 dBm with EVM of less than 3%. Also, it draws 195 ma. The SE2521A80 suits access points and routers. Its higher output power of +20 dBm helps extend the range of operation.
All of the devices feature a 35-dBc adjacent channel power ratio. The power detector has a dynamic range of 20 dB and a digital enable control for transmitter power ramp on/off control. It boosts performance by minimizing mismatch to only 1.5 dB of variation over a 2:1 antenna voltage standing-wave ratio. The T/R switch is a double-pole double-throw circuit designed for diversity-switching two antennas.
All three devices come in a 24-pin LGA package that measures 8 by 7 by 1.1 mm and complies with the lead-free RoHS directives. Samples are available now. Full production is scheduled for the third quarter. Pricing is $1.95 each in 10,000-unit quantities.