David A. Calvillo-Cortes

A 19W high-efficiency wide-band CMOS-GaN class-E Chireix RF outphasing power amplifier

A class-E Chireix outphasing power amplifier is presented that enables high efficiency across a wide power back-off range and RF bandwidth. In this design the Chireix compensation elements and class-E loading conditions are provided by an asymmetric coupled-line power combiner. The class-E operated GaN HEMT switches are driven by high-speed, high-voltage CMOS drivers, implemented in a standard 65nm process technology. The proposed concept demonstrates 51.6% system average power efficiency and 65.1% average drain efficiency for a 7.5dB PAR WCDMA signal at 1.95GHz, while meeting the ACLR specifications. Moreover, the PA demonstrated more than 60% drain efficiency across a 6dB power back-off range and up to 19W peak power between 1800–2050MHz.

A Package-Integrated Chireix Outphasing RF Switch-Mode High-Power Amplifier

This paper describes the design and implementation of a package-integrated Chireix outphasing RF switch-mode power amplifier (PA). The optimum loading conditions, based on class E, and the Chireix compensation elements are provided to the active devices by a dedicated low-loss bondwire-based transformer power combiner that enables a very small form factor and low cost. The realized prototype achieved 70.6-W peak power with 73% peak drain efficiency at 2.3 GHz and 28 V, and up to 81% peak drain efficiency at 2.2 GHz and 20 V. When operated for maximum power at 28 V, it reached 53.5%/43.5% average drain/total efficiency for a 9.6-dB peak-to-average-power-ratio W-CDMA signal at 2.3 GHz with low ACLR1/2 levels ( -49/ -56 dBc after memoryless digital predistortion). Moreover, from 2.1 to 2.4 GHz, the realized PA demonstrated more than 50% drain efficiency across > 260, > 160, and > 80 MHz at 6-, 8-, and 10-dB back-off, respectively.

A 65nm CMOS pulse-width-controlled driver with 8V pp output voltage for switch-mode RF PAs up to 3.6GHz

State-of-the-art wireless communication radios are implemented in deep-submi-cron CMOS, including the RF power amplifiers (PAs). However, in wireless infrastructure systems, the RF PA is often realized in an LDMOS or a compound technology to obtain the required large output powers. For next-generation reconfigurable infrastructure systems, the switch-mode PAs (SMPA) seem to offer the required flexibility for multiband multimode transmitters. In order to interface the high-power devices of the SMPA with the digital CMOS blocks of the transmitter, a wideband RF CMOS driver capable to generate high voltage (HV) swings is required. In this way, digital signal processing can be directly applied to control the required input pulse shapes of the SMPA.

A 70W package-integrated class-E Chireix outphasing RF power amplifier

A high-power class-E Chireix outphasing RF power amplifier integrated inside a transistor package is described. The optimum class-E loading conditions and the Chireix compensation elements are provided to the active devices by a dedicated ultra-low loss bondwire-based transformer power combiner that enables a very small form factor and low cost. The realized prototype achieves 70.6 W peak power with 73% peak drain-efficiency at 2.3 GHz, and up to 81% peak drain-efficiency for slightly lower power at 2.2 GHz. When operated for maximum power, it reaches 53.5%/43.5% average drain-/total-efficiency for a 9.6 dB PAR W-CDMA signal at 2.3 GHz with low ACLR1/2 levels (-49/-56 dBc after memory-less DPD).

A wideband 700W push-pull Doherty amplifier

A push-pull Doherty Power Amplifier (DPA) is proposed that uses a wideband power combiner BALUN, which is capable to provide the optimum fundamental and 2nd harmonic loading conditions over a large operating bandwidth to the active devices. A 700W DPA demonstrator using these techniques provides high average efficiency (> 40%) for a 7.5dB PAR DVB-T signal over a 37% relative RF-bandwidth.

Outphasing transmitters, enabling digital-like amplifier operation with high efficiency and spectral purity

An overview of outphasing transmitters is given. Starting from its basic principles, we discuss its advantages and drawbacks compared to other high-efficiency amplifier configurations. Next, innovations in outphasing architecture, design, and implementation are given that overcome the difficulties related to the traditional outphasing configuration. Using the latest insights in drive schemes for input signals and quasi load-insensitive class-E output matching, very compact high-power high-performance digital- like transmitters are enabled that offer high efficiency and high spectral purity while being reconfigurable in their operating frequency.

On the design of package-integrated RF high-power amplifiers

For wireless infrastructure applications, package-integrated power amplifiers are an appealing approach to achieve improved RF performance in terms of bandwidth and efficiency, as well as lower memory effects, form-factors and cost. This work discusses the specific design and implementation aspects for low-cost package-integrated PAs. Special attention is given to implementation deviations and tolerances when using bondwires. As case study, two class-E RF PA implementations with different bondwire-based output matching networks are evaluated for their predicted physics-based performance versus measured data. The high performance of these PAs shows the potential of these techniques for realizing ultra-compact next generation PA modules.

Analysis of pure- and mixed-mode class-B outphasing amplifiers

This paper analyses the pure- and mixed-mode operation of class-B outphasing amplifiers and provides the analytical expressions for the drive profiles, when assuming ideal devices. In pure-mode operation, output power is controlled by phase modulation only. In mixed-mode operation, amplitude control replaces phase control at the deep back-off power levels to save driving power and hence improve efficiency. Envelope simulations using a 10.6 dB PAR W-CDMA signal verify the analysis of an ideal class-B outphasing amplifier model with only 10 dB of transistors power gain. In mixed-mode operation, they predict up to 65% of average total-efficiency which is 7%-points higher than an equivalent asymmetrical (1:3) Doherty amplifier.