A 2.4-GHz, 2.2-W, 2-V fully-integrated CMOS circular-geometry active-transformer power amplifier

Abstract

A 2.4-GHz, 2.2-W, 2-V fully integrated circular geometry power amplifier with 50 hz input and output matching is fabricated using 2.5V, 0.35 pm CMOS transistors. It can also produce 450mW using a 1V supply. Harmonic suppression is 64dB or better. An on-chip circulargeometry active-transformer is used to combine several push-pull low-voltage amplifiers efficiently to produce a larger output power while maintaining a 50R match.This new on-chip power combining and impedance matching method uses virtual ac grounds and magnetic couplings extensively to eliminate the need for any offchip component such as wirebonds. It also desensitizes the operation of the amplifier to the inductance of bonding wires and makes the design more reproducible. This new topology makes possible a fully-integrated 2.2W, 2.4GHz, low voltage CMOS power amplifier for the first time.

Distributed active transformer-a new power-combining and impedance-transformation technique

“…The distributed active transformer (DAT) is presented as an alternative method to achieve simultaneous impedance transformation and power combining that can be used to overcome 0018-9480/02$17.00 © 2002 IEEE the abovementioned problems [16]. This new method relies on extensive use of symmetric push-pull amplifiers, ac virtual grounds, and magnetic coupling for series power combining.…”

A Fully-Integrated Quad-Band GSM/GPRS CMOS Power Amplifier

“…The large voltage swing on the secondary loop does not pose a reliability issue since no transistor is connected electrically to the output to experience it. More discussion on the detailed operation of DAT can be found in [16]- [20]. In Fig.…”

“…DATs have been shown as the way to solve the first breakdown problem in a fully integrated fashion [16]- [20]. It makes it possible to make fully-integrated watt-level power amplfiers using low-breakdown voltage transistors.…”

“…This situation is exacerbated in CMOS by inductors of lower quality compared with other technologies due to the increasingly highlydoped, conductive substrates. Although watt-level CMOS PAs have been reported in earlier works [12]- [14] dating back to the late 1990s, those PAs as well as more recent research implementations (with the exception of the DAT concept [16]- [20]) require off-chip baluns [21], [22] to meet output power requirement alone or require bonding-wire inductors and large voltage stresses across the transistors [23]. Therefore, fully integrated, transformer-based CMOS PAs typically target standards with lower output power requirements [24].…”

High-Efficiency, Class-E RF Power Amplifiers

“…When all odd harmonics have been short-circuited, the subscript odd is used. In addition to the amplifier reported here, a monolithic CMOS 2.4GHz, 1.5W E/F 3 amplifier is being reported simultaneously [6].…”