A Fully Integrated Bluetooth Low-Energy Transmitter in 28 nm CMOS With 36% System Efficiency at 3 dBm

M. Babaie, F Kuo, H. N. R. Chen, L Cho, C. P. Jou, F. L. Hsueh, M. Shahmohammadi, R. B. Staszewski

Research output: Contribution to journalArticleScientificpeer-review

70 Citations (Scopus)
260 Downloads (Pure)


We propose a new transmitter architecture for ultra-low power radios in which the most energy-hungry RF circuits operate at a supply just above a threshold voltage of CMOS transistors. An all-digital PLL employs a digitally controlled oscillator with switching current sources to reduce supply voltage and power without sacrificing its startup margin. It also reduces 1/f noise and supply pushing, thus allowing the ADPLL, after settling, to reduce its sampling rate or shut it off entirely during a direct DCO data modulation. The switching power amplifier integrates its matching network while operating in class-E/F2 to maximally enhance its efficiency at low voltage. The transmitter is realized in 28 nm digital CMOS and satisfies all metal density and other manufacturing rules. It consumes 3.6 mW/5.5 mW while delivering 0 dBm/3 dBm RF power in Bluetooth Low-Energy mode.
Original languageEnglish
Pages (from-to)1547-1565
Number of pages19
JournalIEEE Journal of Solid State Circuits
Issue number7
Publication statusPublished - 2016


  • Bluetooth
  • CMOS digital integrated circuits
  • MOSFET circuits
  • constant current sources
  • digital phase locked loops
  • low-power electronics
  • oscillators
  • radio transmitters
  • radiofrequency integrated circuits
  • radiofrequency power amplifiers
  • 1/f noise reduction
  • Bluetooth low-energy mode
  • CMOS transistors
  • all-digital PLL
  • class-E-F2 switching power amplifier
  • digitally controlled oscillator
  • direct DCO data modulation
  • efficiency 36 percent
  • energy-hungry RF circuits
  • fully integrated Bluetooth low-energy transmitter architecture
  • metal density
  • power 3.6 mW
  • power 5.5 mW
  • sampling rate reduction
  • size 28 nm
  • supply voltage reduction
  • switching current sources
  • threshold voltage
  • ultra-low power radios
  • CMOS integrated circuits
  • Inductors
  • Oscillators
  • Q-factor
  • Radio frequency
  • Radio transmitters
  • Switches
  • All-digital PLL
  • Bluetooth Low-Energy
  • Internet of Things (IoT)
  • class-E/F 2 power amplifier
  • low-power transmitter
  • low-voltage oscillator
  • switching current-source oscillator


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