A 150/400/800/1900 MHz low noise Cartesian feedback IC with programmable loop bandwidth

A direct conversion, quadruple-band, programmable bandwidth Cartesian feedback linearization IC with flexibility to support multiple linear transmitter applications is presented. Operation at 150, 400, 800, and 1900 MHz frequency bands is obtained via programmable quadrature generators in the forward and feedback paths. The closed-loop transmitter output noise level at a 20 MHz offset from the carrier is -152 dBm/Hz at 0 dBm average output power. The unity gain baseband loop bandwidth is adjustable via programming over a 50 KHz - 500 KHz range to support RF modulation bandwidths up to 150 KHz. 45 dB of power output level adjustment is provided in 5 dB steps, using selectable scaled modulators to conserve current drain at lower power settings. The IC is implemented in the 1BM 6HP 0.25 µm BICMOS process, and operates on 2.7 V analogue and 1.8 V digital supplies.