Fully integrated CMOS power amplifier design using the distributed active-transformer architecture

Abstract

Abstract-A novel on-chip impedance matching and powercombining method, the distributed active transformer is presented. It combines several low-voltage push-pull amplifiers efficiently with their outputs in series to produce a larger output power while maintaining a 50-match. It also uses virtual ac grounds and magnetic couplings extensively to eliminate the need for any offchip component, such as tuned bonding wires or external inductors. Furthermore, it desensitizes the operation of the amplifier to the inductance of bonding wires making the design more reproducible. To demonstrate the feasibility of this concept, a 2.4-GHz 2-W 2-V truly fully integrated power amplifier with 50-input and output matching has been fabricated using 0.35-m CMOS transistors. It achieves a power added efficiency (PAE) of 41% at this power level. It can also produce 450 mW using a 1-V supply. Harmonic suppression is 64 dBc or better. This new topology makes possible a truly fully integrated watt-level gigahertz range low-voltage CMOS power amplifier for the first time.

Extremely wideband signal shaping using one- and two-dimensional nonuniform nonlinear transmission lines

“…For example, these bottlenecks arise in high-frequency fully-integrated power amplifier design. 1,2 These same considerations hold for the wider class of active devices. Even if we restrict consideration to siliconbased technologies, active devices are technology dependent, making it difficult to port the design from one complementary metal-oxide semiconductor ͑CMOS͒ technology to another.…”

The future of high frequency circuit design

“…This is mainly due to the lower transistor breakdown voltages resulting from the scaling process and the shrinking of the depletion regions in the transistors, which necessitates the use of a lower power supply voltage. Unfortunately, this is in direct conflict with the maximum power that can be generated using conventional power amplifier techniques, which makes it almost inevitable to use parallel structures and novel power combing approaches, as described in [13] [14] and [28]- [31]. These approaches in turn are more susceptible .to different energy loss mechanism in passive devices that were dIScussed earlier.…”

A 21-26-GHz SiGe bipolar power amplifier MMIC

“…For example, the distributed active transformer (DAT) presented in [43] functions as an eight-way combiner which produces 2 W of output power at 2.4 GHz using CMOS driver transistors. Fig.…”