A low power flexible analog baseband for low-IF Zigbee receiver

An analog baseband chain for a low-IF Zigbee receiver is implemented in a 0.18-μm CMOS process. The analog baseband consists of a variable gain complex channel filter with on-chip automatic frequency tuning and two decibel linear programmable gain amplifiers (PGA). The phased-locked loop (PLL) based master-slave frequency tuning scheme keeps the complex filter characteristic immune to process and temperature. Measurements results indicate that the analog baseband provides a gain control range from 9 dB to 65 dB. The analog baseband dissipates 2.51mA from a 1.8 V supply and the chip core area is 0.85mm2.