A 0.8/2.4 GHz Tunable Active Band Pass Filter in InP/Si BiCMOS Technology

A tunable active band pass filter (BPF) has been designed in a chip-scale heterogeneous integration technology, which intimately integrates InP HBTs on a deep scaled CMOS technology. The BPF test chip consists of a programmable gain amplifier (PGA), a BPF core, and a buffer. The chip features a frequency tuning range from 0.8 to 2.4 GHz with 150 MHz pass band and four gain steps: 0, 6, 12, and 16 dB. The BPF core employs active-RC architecture for high linearity by leveraging the >300 GHz fT of InP HBTs and the programmability of CMOS. The test chip occupies 1.7×1.25 mm² area including pads and draws 85/110 mA from a 3.5 V power supply for 0.8/2.4 GHz bands, respectively. In addition, it demonstrates out-of-band IIP3s of 21.97/16.87 dBm for 0.8/2.4 GHz bands at the high gain mode, which suggests the BPF core delivers 37.97/32.87 dBm out-of-band IIP3s.