Microwave Journal

Freescale Introduces Three RF LDMOS Power Transistors

September 28, 2010

Freescale Semiconductor introduces three new RF LDMOS power transistors that deliver ultra high output levels required for Doherty-type, multi-carrier power amplifiers (MCPA) used in wireless base station transceivers.

Freescale’s MRF8S18260H/S, MRF8P18265H/S and MRF8S19260H/S products are the newest members of Freescale’s High Voltage Eighth Generation (HV8) family of RF power amplifiers. They deliver the highest output levels in Freescale’s RF LDMOS power transistor portfolio for the 1800 and 1900 MHz bands.

MCPAs allow wireless service providers to increase the coverage and capacity of their existing base stations without dedicating one amplifier per carrier, as was often required in the past. MCPA technology allows a single amplifier to handle multiple carriers, thereby decreasing the size and component count of end products. In addition, Doherty configurations make the power amplifier more energy efficient, lowering the base station’s annual operating costs.

“We designed Freescale’s HV8 portfolio to offer designers increased operating efficiency in order to lower the total power consumption of a base station system and reduce operating costs,” said Gavin P. Woods, Vice President and General Manager of Freescale’s RF Division. “The addition of these advanced MCPAs, the MRF8S18260H/S, MRF8P18265H/S and MRF8S19260H/S, expands our LDMOS offerings to provide our customers an even wider selection to meet their design needs to specifically address the broad range of wireless service provider requirements.”

The new products satisfy the unique requirements of the Doherty amplifier architecture, in which a carrier amplifier operating in Class AB mode is combined with a peaking amplifier operating in the higher-efficiency Class C mode. Their characteristics also make them well suited for use with digital predistortion (DPD) circuits that maintain the high linearity demanded by higher-order modulation schemes.

The transistors are internally matched for simplified assembly, are extremely rugged and can produce their rated power into a 10:1 VSWR at 32 VDC. They are housed in Freescale’s NI1230 ceramic air-cavity packages and have integrated electrostatic discharge (ESD) protection that makes them more resistant to stray voltage encountered on assembly lines, and their broad gate voltage range of -6 to +10 V increases their performance when operating in Class C mode.

The MRF8P18265H/S is a dual-path device in which both carrier and peaking amplifiers required to implement a Doherty final stage amplifier are integrated within a single package.