High linearity-wideband PHEMT Darlington amplifier with +40 dBm IP3

Abstract

This paper reports on a 0.1-3 GHz broadband matched Darlington feedback amplifier with over 40 dBm of OIP3 operating from a 5V supply. The Darlington performance is enabled by 0.5um Emode PHEMTs with fT ~ 30 GHz. The PHEMT Darlington achieves 13 dB of gain at 2 GHz and is monolithically matched to 50 ohms across a wide 0.1-3 GHz bandwidth. The IRL and ORL are better than 15 dB across the band. Noise figure of 3.3 dB and OIP3 of 41.4 dBm are achieved at 2 GHz with a P1dB compression of 21.8 dBm. The monolithically matched amplifier achieves > 40 dBm IP3 across a wide 3 GHz band.The total current consumption is only 115 mA through a 5V supply and the LC-measured junction temperature is less than 125C @ 85C base-plate. These are believed to be the best IP3 results reported for a 5V wide band Darlington feedback amplifier at 2 GHz and above.

A Broadband Gain Amplifier Designed with the Models for Package and Diode Using 0.5 μm GaAs E-pHEMT Process

“…In addition, with the recent evolution of communication systems such as 5 G (Sub-6 GHz) and Wi-Fi 6/6E, a broadband gain amplifier including additional frequency bands is strongly required [1,2]. For bands from the near DC to the 5 GHz band, gain amplifiers using various techniques have been reported [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, it is not easy to keep the S 21 flatness for a wide frequency band due to the difficulty to realize the matching circuit for varying impedance over frequency.…”

“…For broadband amplifier designs, Darlington amplifiers with feedback have been widely used due to the advantage of allowing wideband impedance matching without additional circuitry [6][7][8]. They have a structure that combines the output signals at the common drain of two transistors.…”