David C. Dening

High-Efficiency Cellular Power Amplifiers Based on a Modified LDMOS Process on Bulk Silicon and Silicon-On-Insulator Substrates With Integrated Power Management Circuitry

An RF high-voltage CMOS technology is presented for cost-effective monolithic integration of cellular RF transmit functions. The technology integrates a modified LDMOS RF power transistor capable of nearly comparable linear and saturated RF power characteristics to GaAs solutions at cellular frequency bands. Measured results for multistage cellular power amplifier (PA) designs processed on bulk-Si and silicon-on-insulator on high-resistivity Si substrates (1 kΩ·cm ) are presented. The low-band multistage PA achieves greater than 60% power-added efficiency (PAE) with more than 35.5-dBm output power. The high-band PA achieves 45%-53% PAE across the band with greater than 33.4-dBm output power. Measured linearity performance is presented using an EDGE modulation source. A dc/dc buck converter was also integrated in the PA die as the power management circuitry. Measured results for the output power, PAE, and spurious emissions in the receive band while the dc/dc converter is biasing the PA and running at different modes are reported.

A Flip-Chip Silicon IPMOS Power Amplifier and a DC/DC Converter for GSM 850/900/1800/1900 MHz Systems

An LDMOS-based MOS device, called integrated power MOS (IPMOS), was developed to provide integration of high-performance reliable RF power devices with the rest of the front-end using flip-chip packaging. A 3-stage power amplifier (PA) die containing 1-8-30 and 1-8-40 mm wide IPMOS devices was designed for GSM 1800/1900 and GSM 850/900 MHz systems, respectively. The PA for GSM 850/900 achieved power added efficiencies (PAE) in the range of 54 to 62 % across the band with output power (Pout) ranging from 34.5 to 35.4 dBm when driven with input power (Pin) greater than 3 dBm. The PA for GSM 1800/1900 achieved PAEs in the range of 39 to 42 % with Pout ranging from 32.5 to 33.7 dBm when driven with Pin greater than 4 dBm. A DC/DC buck converter was also designed using the same process, and the bias to the PA for GSM 850/900 was applied through this converter. PAEs when Pin and DC/DC converter output voltage are varied were compared.

Integration of a cellular handset power amplifier and a DC/DC converter in a Silicon-On-Insulator (SOI) technology

A DC/DC buck converter was integrated with a cellular handset power amplifier (PA) in a silicon-on-insulator (SOI) technology. The technology was designed to allow integration of high-performance reliable RF power devices with the front-end. The power devices uses an LDMOS-based MOS device, called integrated power MOS (IPMOS). A 3-stage power amplifier was designed for GSM850/900 and DCS/PCS bands. The PA achieved typical power added efficiencies (PAE) greater than 60% with Pout ranging from 35.5 to 36.7 dBm at GSM850/900 MHz band, and it achieved typical PAEs in the range of 44 to 49 % with Pout ranging from 33.6 to 33.8 dBm at DCS/PCS band. The PAE was also measured when the DC/DC converter biased the PA. Up to 25-percentage-point improvement in the PAE was observed compared to the case where the output power was controlled by varying the input power. The spurious emissions in the transmit band and the receive band noise were also reported.

Broadband reconfigurable matching network of reduced dimensions for the UHF military satellite communication band

In a wireless communication system, a good impedance match between the transmitter and the antenna is essential in order to achieve power efficient operation and maximize the effective radiated power (ERP). In portable scenarios, the antenna impedance is usually subject to wide variations, mostly due to its interaction with objects in the near field. This paper presents a miniature reconfigurable matching network that utilizes a novel circuit topology that minimizes insertion loss due to switch resistance and provides a wide range of impedance match over a bandwidth that exceeds one octave. The network can be implemented in a very small area, which makes it attractive for portable radios. Experimental results are provided for a unit designed for the military UHF satellite communication band that occupies the 220 to 450 MHz spectrum.

A Buck-or-Boost Converter Module With Embedded Inductor and Fast Current Limit

The operation and performance of a four-switch buck-or-boost converter are presented with peak efficiencies greater than 90% under various loads. The converter is demonstrated in a module format where the single inductor is embedded within the laminated module substrate. Nominal inductance is 2 μH and dc resistance is 120 mΩ. The converter provides a fast-acting current limit function when the sensed inductor current exceeds about 1 A.