Analog Baseband-IC for Dual Mode Direct Conversion Receiver

This paper presents a circuit design and implementation for the analogous filter and amplifier sections of a direct conversion receiver. Dual-mode operation is achieved by switching the LP-filters´ cut-off frequency to meet DECT and DCS 1800 specifications alternatively. An op-amp-based integrator loop filter structure is used to perform low-noise, low-voltage and low-power operation. The circuit is fabricated using a 1.5¿ BiCMOS process. Including a DECT demodulator and a RSSI circuit the whole two-channel circuit drains 4 mA from a 3 V power supply.