Mobile handsets must pack a great deal of functionality within a compact package to even approach modern customers' expectations. In order to handle different bands and operating modes, RF front-end modules (FEMs) typically employ low-noise amplifiers (LNAs) and filters for each receiver band, and power amplifiers (PAs) and filters for each transmit band. But Fujitsu Microelectronics America has found a way to eliminate the space-eating surface-acousticwave (SAW) filters and some amplifiers commonly found in these FEMs, and has embodied this design approach in its model MB86L10A transceiver module for second-generation (2G) cellular, third-generation (3G) cellular, and Long Term Evolution (LTE) cellular handset applications. The FEM supports GSM, WCDMA, and LTE frequency-divisionduplex (FDD) and time-division-duplex (TDD) bands, in a compact 6.5 x 9.0 x 1.0 mm LGA housing.
The MB86L10A transceiver builds on the firm's earlier model MB86L01A 3G cellular radio transceiver (see Microwaves & RF, October 2009, p. 114), which was aimed at Third Generation Partnership Program (3GPP) wideband- code-division-multiple-access (WCDMA)/EGPRS handsets. The MB86L10A features quad<band GSM/ EDGE and as many as five WCDMA or LTE bands. Its coverage includes GSM850, EGSM900, DCS1800, PCS1900, WCDMA bands I, II, III, IV, V, VI, VIII, IX, X, and XI, LTE-FDD bands 1, 3, 4, 6, 7, 8, 9, 10, 11, 13, and 17, and LTE-TDD bands 38 or 50.
The transceiver module provides eight transmitter output ports that can directly drive PAs (without filtering) and 14 differential RF input receiver ports. Nine of the receiver's input ports support LTE, WCDMA, and GSM/ EDGE, while the five remaining ports support receive diversity in WCDMA and LTE modes. All of these ports can be used without the usual SAW filters, greatly simplifying the complexity of a multimode handset design. The model MB86L10A module provides simultaneous support for 3G and 4G interfaces and can be teamed with one or two baseband processors, depending upon the requirements of a handset design. It is compatible with a wide range of baseband architectures via a high-level programming model that controls the radio using 3G and 4G DigRF/MIPI open-standard digital interfaces to the baseband processor integrated circuit (IC) or circuits.
The highly integrated module is fabricated with a 90-nm CMOS process. In addition to transmit digital-toanalog converters (DACs) and receive analog-to-digital converters (ADCs), the device includes a transmit voltagecontrolled oscillator (VCO), transmit synthesizer, transmit modulator, receive downconversion mixers, filtering, and on-board amplification. In addition, a microcontroller in the transceiver simplifies timing and control.
According to Vivek Bhan, Senior Director of RF Engineering and Product Development for Fujitsu Microelectronics America, "The Fujitsu MB86L10A LTE multimode transceiver is the first of its kind to eliminate LNAs and 3G/4G TX and RX SAWs, reducing board area, component count, and cost. This LTE multimode RF transceiver supports most global band configurations and standard interfaces, and its simple RF API programming reduces radio integration time." The MB86L10A, with a number of automated self-calibration routines, is in pre-production and in field trials for a major carrier. The field trial is exercising the new device in 2G, 3G, and 4G modes across multiple bands and both DigRF interfaces. Fujitsu Microelectronics America, Inc., 1250 E. Arques Ave., Mail Stop 333, Sunnyvale, CA 94085-5401; (800) 866-8608, FAX: (408) 737-5999, e-mail: [email protected], Internet: http://us.fujitsu.com/micro/rftransceiver.