Duplexer and power amp come together

A novel front-end module provides the industry's first combined CDMA duplexer/power amplifier for use in dual-band and US PCS mobile phones and wireless data cards.

A new front-end module (FEM) provides the industry's first combined CDMA duplexer/power amplifier for use in dual-band and US PCS (Personal Communications Service) mobile phones and wireless data cards.

This integration of two industry-best technologies enables manufacturers to produce smaller-size handsets with higher power-added efficiency, which means more functionality, extended battery life and longer phone talk time.

The module's miniature size also helps manufacturers trim costs via an up to 50% savings in board space, and an up to 65% reduction in parts count, including passive components.

"Our FBAR duplexers and filters offer the industry's smallest size and excellent performance with steep roll-off, low insertion loss and low temperature coefficient", said Bryan Ingram, Vice President and General Manager of Agilent's Wireless Semiconductor Division.

"Our E-pHEMT power amps provide the industry's best power-added efficiency, enabling longer battery life and more talk time.

The combination of these two innovative technologies in a compact 'by-band' RF front-end module gives our handset customers faster time to market, better performance through optimised impedance matching, and greater board-space savings to make room for additional handset features".

Strong demand from handset manufacturers continues to fuel combined shipments of Agilent's E-pHEMT power amplifiers and FBAR duplexers at a rate of more than four million units per month.

The Agilent AFEM-7731 announced today is a fully matched CDMA-1900MHz FEM, integrating Agilent's highly efficient ACPM-7833 E-pHEMT (enhancement-mode pseudomorphic high electron mobility transistor) power amplifier with its miniature ACMD-7401 FBAR (film bulk acoustic resonator) duplexer and all matching circuitry into a compact 5 x 8 x 1.3mm chip-on-board module.

Compared with designs using separate power amplifiers and duplexers, the AFEM-7731 features higher effective power-added efficiency (PAE) for longer talk time, and high isolation and low loss in the receive band for high sensitivity.

The optimised matching between the power amplifier and duplexer eliminates the need for a bulky and costly isolator, which further reduces the cost and size of the handset.

Mobile phone frequency bands and air interface standards differ by geography, and so multiband, multimode handsets need a certain combination of frequency bands and standards to meet local radio requirements.

Handset radio front-end architectures need to be flexible to work with these various combinations.

"By-band" front-end modules that are partitioned by frequency band (for example, 1900 and 850MHz) can be used in any phone with a CDMA-1900MHz PCS band.

For example, Agilent's AFEM-7731 can be used in single-band and dual-band CDMA handsets, and in multiple-air-interface phones such as those with CDMA, W-CDMA and GSM.

Agilent is developing a variety of modules using this by-band approach.

In addition to its small footprint and ultrathin size, the AFEM-7731 RF FEM offers these features for handset and data card design: 3.4V operation (3.2V minimum); high efficiency, with low current (380mA typical current at 24.5dBm linear output power) providing approximately 50mA current saving; low quiescent current implemented using fixed and dynamic bias control; and high isolation (low transmitter leakage at the receiver port).

The AFEM-7731 is shipping in prototype quantities through Agilent's direct sales channel to select mobile phone manufacturers.

Production volumes are expected by Q3 2004.

Pricing at full product release is expected to be similar to the combination of separate Agilent ACPM-7833 (CDMA E-pHEMT power amplifier module) and ACMD-7401 (CDMA FBAR duplexer) devices.

Agilent is also developing a cell-band CDMA 850MHz RF front-end module, which it expects to ship in volume by Q4 2004.

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