A Low-Power Continuous-Time Low-Pass Analog Filter for IEEE 802.11 a/b/g/n Wireless LANs

A Low-Power Continuous-Time Low-Pass Analog Filter for IEEE 802.11 a/b/g/n Wireless LANs

A low-power continuous-time low-pass analog filter suitable for IEEE 802.11 a/b/g/n wireless LANs with directconversion scheme is designed. The filter topology is based onGm-C biquads. For the filter to become low-power, inverterbased transconductors with suitable common-mode feedback andfeed forward circuitries are used. The output resistance of each OTA is increased by a negative parallel resistance at the output nodes. In order to compensate the process variation effects, oneof the newest automatic tuning method called bulk-tuning is employed. With a 1.3-V supply voltage, this filter consumes 600μW per biquad and the IIP3 of 10.2 dBm, 9.3 dBm and 9.0 dBm is achieved for IEEE 802.11 (a,g)/b/n direct conversion modesrespectively with flat pass-band frequency response and near - 40dB/dec stop-band gain reduction slope (per biquad).