Handset power amps shift to CMOS

The new Stratos CMOS power amplifier product family will enable manufacturers to deliver smaller phones with greater than 20% improvement in usage time.

Amalfi Semiconductor has come up with the industry's first CMOS-based power amplifier chip for GSM/Edge cellular handset phones.

The AM8901 power amplifier is part of the company's new Stratos CMOS power amplifier product family for cellular phone applications.

The product family is based on an innovative CMOS silicon architecture that reduces the battery's electrical current requirements in cellular phones.

This reduction sets a new performance standard in the cellular industry that will enable manufacturers to deliver phones with greater than 20% improvement in usage time, thinner designs and additional functionality, such as mobile TV, MP3 player and video camera.

Amalfi's CMOS power amplifiers also improve manufacturability and lower overall system cost of cellular phones.

According to Jagdish Rebello of iSuppli: "The mobile handset market is estimated to grow from 1.15 billion unit shipments in 2007 to over 1.54 billion unit shipments in 2011".

"CMOS is the dominant technology used in today's cellular handsets for most functions with the notable exception of the power amplifier".

"The power amplifier has proven to be the most challenging, but once CMOS can match the performance of existing GaAs solutions, it will only be a few years before CMOS also dominates this function".

Differing from other power amplifiers, Stratos power amplifiers use an industry standard bulk CMOS manufacturing process.

Amalfi's AdaptiveRF silicon architecture was specifically designed for the development of CMOS power amplifiers and has proven to achieve competitive peak performance and better power added efficiency in the typical operation ranges relative to leading GaAs power amplifiers.

For example, a GaAs PA device would need to exceed 60% PAE at maximum output power to match Amalfi's performance in the mid-range operating power levels applicable to GSM and Edge cellular mobile handsets.

"We have demonstrated that our Stratos CMOS power amplifiers with AdaptiveRF technology can outperform GaAs in many significant metrics", says Jim Finch, cofounder and CEO of Amalfi Semiconductor.

"In the most important area of battery life or usage time, we are able to deliver an entirely new efficiency curve to the industry that will enable a revolutionary change in future designs and performance capabilities of cellular handsets".

"This is just the beginning for CMOS power amplifiers in the cellular handset market".

Today's GaAs power amplifiers typically draw between 0.3 and 3W during cellular transmission, which represents 30-70% of the electrical current used by the phone when the user is talking.

The lower power consumption resulting from the Stratos power amplifiers increase the battery capacity enabling the cellphone to support more talk time or other high-end mobile functions, potentially increasing revenue opportunities for cellular telephone carriers.

This capability will also allow cellular manufacturers to use smaller, less expensive batteries, reducing the size and cost of the phone.

The Stratos AM8901 GSM/Edge power amplifier achieves better PAE over the leading GaAs power amplifiers for GSM/Edge applications under real-world operating conditions of reduced output power, low battery voltage and antenna mismatch.

This greater PAE extends the usage time of the phone by greater than 20%.

The higher levels of integration available with CMOS also allow for the addition of intelligent control circuitry that continually monitors and adjusts for greater calibration accuracy and more consistent power control over a wider operating range.

In addition to the Stratos AM8901, Amalfi has also released the Stratos AM8801, a CMOS-based power amplifier for GSM/GPRS cellular mobile handsets.

Both chips are extended high-efficiency, quad-band CMOS power amplifiers that offer the following advantages to cellular handset manufacturers.

The Stratos product family is sampling to Amalfi Semiconductor's development partners.

The AM8801 will be available in volume production in the second half of 2008 and the AM8901 will begin production release in Q1 2009.

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