Power amp boosts wireless network range

The RangeCharger SE2522BL power amplifier delivers a combination of high output power and power control features to improve transmission range and efficiency of IEEE802.11b wireless access devices.

The SiGe Semiconductor RangeCharger SE2522BL power amplifier delivers a combination of high output power and power control features to improve transmission range and efficiency of wireless access devices compliant to the IEEE802.11b WLAN specifications.

The SE2522BL is capable of +23dBm of linear output power at an adjacent channel power ratio (ACPR) of -30dBc.

Considering the 2-3dBm losses typical of most WLAN systems, this performance allows designers to easily achieve 20dBm at the antenna.

This improves stability and transmission range, making it ideal for applications like wireless access points and PCMCIA cards operating in the unlicensed 2.4GHz frequency band.

SiGe's new SE2522BL power amplifier is pin compatible to the company's SE2522L power amplifier, announced in August.

These two devices allow customers to maintain the same system layout for multiple application requirements.

A system designed with the high output power SE2522BL allows longer transmission range in products like access points, which generally operate using higher current consumption.

The same layout, using the low-power SE2522L enables battery-powered applications that don't require maximum output power.

"The ability to leverage a system layout for multiple applications provides our customers with a major advantage in the race to bring next-generation products to market", said Bill Cuming, Vice President Optical, Cable and Components, SiGe Semiconductor.

"Coupled with our track record in performance and power efficiency, customers can now serve several market niches with the confidence that all user requirements for performance, stability and transmission range are met".

The SE2522BL operates at a typical current consumption of about 240mA, about 50-70mA less than other power amplifiers on the market with the same output power.

The low current consumption results from integrated power control and detect features, as well as an efficient silicon germanium structure that provides high thermal conductivity and low junction temperature.

The integrated power detector has an input range of 15dB, and an accuracy of +/-1.0dB.

The detector can be used with a power control feature in a closed-loop system that allows the baseband controller to lower the power amplifier output power via a single control pin.

Using the control pin allows the current consumption to be reduced in proportion to the output power.

This is far more efficient than alternative methods of reducing output power, such as attenuating the output signal using external components, or reducing the input signal power, which require the power amplifier to draw the standard operational current.

The integrated power detect and control features reduce cost by eliminating external components typically required to implement the power detect functionality.

This also lowers manufacturing cost, since having fewer components makes it easier to calibrate the system.

SiGe's SE2522BL is sampling now, supplied in a small-outline 8-lead LPCC package that is efficient for miniature designs.

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