Name
Title | ||
|---|---|---|
A 4.75-GHz Fractional Frequency Divider-by-1.25 With TDC-Based All-Digital Spur Calibration in 45-nm CMOS |
Abstract | ||
|---|---|---|
This paper presents a fractional frequency divider-by-1.25 and associated all-digital calibration circuitry. The divider can be used in a wireless transceiver to prevent direct or harmonic pulling of the VCO by the power amplifier. Timing errors between the quadrature phases used in the phase-rotating divider introduce fractional spurs at the output. In this design, the timing errors are measured with a stochastic time-to-digital converter with 20 fs resolution, and corrected to suppress output spurs. The fractional divider has been implemented in a 45 nm CMOS LP process and its core dissipates an estimated 17 mA current from a 1.1 V supply. After calibration, fractional spurs are on average below -59 dBc and -50 dBc (¿ ~ 2 dB over 10 samples) with a 2.5 and 3.8 GHz output frequency respectively. Calibration performance has been confirmed for temperatures from -20°C up to 85°C. The low spur level facilitates radio co-existence with no need for additional filtering. This makes this divider a good candidate for WiFi and WiMAX radios up to 3.8 GHz. |
Year | DOI | Venue |
|---|---|---|
2009 | 10.1109/JSSC.2009.2032276 | Solid-State Circuits, IEEE Journal of |
Keywords | Field | DocType |
CMOS integrated circuits,frequency dividers,power amplifiers,transceivers,voltage-controlled oscillators,CMOS LP process,TDC-based all-digital spur calibration,VCO,WiFi radios,WiMAX radios,current 17 mA,fractional frequency divider,frequency 2.5 GHz,frequency 3.8 GHz,phase-rotating divider,power amplifier,quadrature phases,size 45 nm,stochastic time-to-digital converter,temperature -20 degC to 85 degC,timing errors,voltage 1.1 V,wireless transceiver,Delay mismatch,WLAN,WiMAX,fractional frequency divider,phase-rotating frequency divider,power amplifier pulling,spur calibration,time-to-digital converter | Transceiver,Frequency divider,Computer science,Harmonic,CMOS,Voltage-controlled oscillator,Electronic engineering,dBc,Electrical engineering,Time-to-digital converter,Amplifier | Journal |
Volume | Issue | ISSN |
44 | 12 | 0018-9200 |
Citations | PageRank | References |
22 | 2.92 | 9 |
Authors | ||
3 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Stefano Pellerano | 1 | 191 | 32.98 |
| Paolo Madoglio | 2 | 91 | 13.34 |
| Yorgos Palaskas | 3 | 226 | 32.58 |