A Low-Power Continuous-Time Low-Pass Analog Filter for IEEE 802. 11 a/b/g/n Wireless LANs
Keywords:
bulk-tuning; direct-conversio; Gm-C biquad; IEEE 802. 11 a/b/g/; low-power.
Abstract:
A low-power continuous-time low-pass analog filter suitable for IEEE 802. 11 a/b/g/n wireless LANs with directconversionscheme is designed. The filter topology is based on Gm-C biquads. For the filter to become low-power, inverterbasedtransconductors with suitable common-mode feedback and feedforward 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, one of the newest automatic tuning method called bulk-tuning is employed. With a 1. 3-V supply voltage, this filter consumes 600 µW 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 modes respectively with flat pass-band frequency response and near 40dB/dec stop-band gain reduction slope (per biquad).