Implementation of CMRC on HBT power amplifier for WCDMA application

An InGaP/GaAs heterojunction bipolar transistor (HBT) is developed. By using this HBT, a power amplifier is designed for WCDMA user equipment, band-1 power class-2 application. The HBT power amplifier demonstrates a maximum output power (Pout) of 29.4dBm and a PAE of 48% at the frequency of 1.95GHz. When it operates in WCDMA standard, it achieves a Pout of 27dBm and a PAE of 32.4%. The Adjacent Channel Leakage power Ratio (ACLR) is -33dBc. To further improve the PAE, ACLR and IM3 performance, a CMRC circuit has been implemented on the HBT amplifier. The effect of CMRC on PAE and ACLR is investigated using a low power HBT amplifier. The results show that the ACLR can be improved by the CMRC. © 2004 IEEE.published_or_final_versio

Analysis on accuracy of charge-pumping measurement with gate sawtooth pulses

Charge-pumping (CP) measurement is performed on MOSFETs with their gates tied to sawtooth pulses. Influence of both rise time (tr) and fall time (tf) on the CP current of the devices with different channel lengths is investigated at different pulse frequencies. Results show that the dominant mechanism affecting the measurement accuracy is the energy range of interface-trap distribution Dit(E) swept by the gate signal for frequencies below 500 kHz and carrier emission for frequencies above 500 kHz. For frequencies higher than 600 kHz, incomplete recombination could be an additional mechanism when tf is too short. Hence, it is suggested that low frequency is more favorable than high frequency, especially for sawtooth pulses with long tr and short tf , due to little carrier emission and negligible geometric effects even for devices as long as 50 μm. However, if high frequency (e.g. 1 MHz) is required to obtain a sufficiently large S/N ratio in the CP current, sawtooth pulses with equal tr and tf should be chosen for the least carrier emission effect and thus more reliable results on interface-state density, Moreover, for both sawtooth and trapezoidal pulses with a typical amplitude of 5 V, a lower limit of 200 ns for tr and tf is necessary to suppress all the undesirable effects in devices shorter than at least 20 μm.published_or_final_versio

InGaP/GaAs HBT power amplifier with CMRC structure

An InGaP/GaAs heterojunction bipolar transistor (HBT) power amplifier is developed for WCDMA user equipment, specifically, band-1-power class-2 application. The HBT power amplifier demonstrates maximum output power P out of 29.4 dBm and power-added efficiency (PAE) of 48% at a frequency of 1.95 GHz. When operated according to the WCDMA standard, it achieves Pout of 27 dBm and PAE of 32.4%. The adjacent channel leakage power ratio (ACLR) is -33 dBc. A compact microstrip resonant cell (CMRC) circuit is implemented on the HBT amplifier in order to further improve the PAE, ACLR, and IMS performances. This results in improvements of 8 dB and 6% for the ACLR and PAE, respectively. © 2005 Wiley Periodicals, Inc.link_to_subscribed_fulltex