Improving Performance of InGaP/GaAs HBT Arrays by means of Temperature-Dependent Base Ballasting Resistors

Base ballasting resistors (BBRs) are commonly adopted to minimize electrothermal(ET) effects in arrays of bipolar transistors for power amplifier (PA) applications. In this paper, innovative BBRs with temperature-dependent resistivity are proposed in order to improve the trade-off between safe-operating area (SOA) and radiofrequency (RF) performances. As a simple case-study, a three-cell heterojunction bipolar transistor (HBT) fabricated by Qorvo is considered and circuital ET simulations are performed in ADS. Results of the comparison between the proposed strategy and the traditional one are discussed, thus providing useful insights into the advantages of temperature-dependent BBRs.