A FULLY INTEGRATED MOS-C CURRENT-MODE IF FILTER FOR BLUETOOTH by Hussain Alzaher Electrical Engineering Department King Fahd University of Petroleum & Minerals Dhahran Saudi Arabia

Outline  Introduction Bluetooth technology Receiver Architecture  Requirements of IF Filter  Proposed Technique Unity gain cells Non-Linearity Cancellation Fully Differential Architecture  Proposed Low IF Bandpass Filter Filter design topology Filter characteristics  Simulation Result ac response Filter specifications  Conclusions

Introduction Bluetooth technology small, low-cost, short-range radio link mobile computing and communications between wireless devices frequency hopping spread spectrum multiple access technique 79-hopping channels spaced 1-MHz apart data transmission rate of 1 Mb/s Gaussian frequency shift keying relaxed dynamic range, noise figure and image rejection specifications

Introduction Bluetooth Receiver Architecture Low-IF architecture

Center frequency (f c ): 3MHz Filter bandwidth: 1MHz Selectivity  f c ±1MHz  f c ±2MHz  f c ±3MHz (or more) Dynamic Range  IP3-Noise > 75dB In-band group delay < 1us Requirements of IF Filter

Proposed Technique Unity gain cells CharacteristicsVoltage BufferCurrent Follower RelationsV output =V input I output = I input V input =0 Input impedance Very High Ideally =infinity Very Low Ideally=zero Output Impedance Very Low Ideally=zero Very High Ideally =infinity Unity gain cells terminal characteristics

A CMOS Low-power Current follower Proposed Technique Unity gain cells

Proposed Technique Unity gain cells A CMOS Low-power Voltage-buffer

Proposed Technique Non-Linearity Cancellation Ohmic Region MOSFET Current Linearized MOSFET Resistor Basic Circuit

Proposed Technique Non-Linearity Cancellation Nonlinearity cancellation using CFs

Proposed Technique Fully Differential Architecture Fully differential building block topology

Proposed Technique Fully Differential Architecture Fully differential building block CMOS realization

Proposed Low IF Bandpass Filter RC-Unity Cells two-integrator loop filter Filter design topology

Proposed Technique Filter design topology Proposed second-order bandpass filter section

Proposed Technique Filter design characteristics

Proposed Technique Filter die photo

Simulation Result Magnitude response

Receiver Architectures 340nV/ ParametersSpct.Results V DD -2.5V I DD - mA Center frequency-3Meg Order12 th (6 th +three 2 nd ) Passband gain- Frequency tuning Meg Group delay<1us<0.5us 1 st blocker attenuation0dB>7dB 2 nd blocker attenuation30dB>34dB 3 rd /more blocker attenuation 40dB>44dB In-band noise input referred Noise - IIP3-Noise>75dB80dB(inband) 84dB(near blockers) 91dB(distant blockers) Area1.7 mm x 1.7 mm

Conclusions CMOS bandpass filter for fully integrated Bluetooth receiver Using unity gain cells Utilizing linearized MOSFET resistors for tuning 12 th order = 3 X 2nd order bandpass + 3 X 2nd order notches Dynamic range = 53dB for in-band signals Selectivity improved by cascading Current consumption can be optimized