A crystal-less bluetooth low energy radio using a MEMS-based frequency reference system

A system clock is implemented with a 2.52 GHz MEMS-based oscillator, divider, temperature sensor, digital PLL, and active temperature compensation to generate a 48 MHz frequency reference with ±10 ppm stability from -40°C to 105°C. An on-chip 32 kHz RC oscillator is also periodically calibrated by t...

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Bibliographic Details
Published in2017 Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS) pp. 181 - 184
Main Authors Griffith, Danielle, Yen, Ernest Ting-Ta, Roine, Per Torstein, Kaichien Tsai, Kallerud, Torjus, Goodlin, Brian
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.07.2017
Subjects
Bluetooth Low Energy (BLE)
Clocks
crystal-less
Frequency measurement
frequency reference
MEMS resonator
oscillator
Oscillators
Resonant frequency
system-on-chip (SoC)
Temperature measurement
Temperature sensors
Thermal stability
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Summary:A system clock is implemented with a 2.52 GHz MEMS-based oscillator, divider, temperature sensor, digital PLL, and active temperature compensation to generate a 48 MHz frequency reference with ±10 ppm stability from -40°C to 105°C. An on-chip 32 kHz RC oscillator is also periodically calibrated by this reference clock to achieve ±500 ppm accuracy, allowing it to be used as the wireless node sleep timer. Additionally, the MEMS oscillator is advantaged in highly duty cycled protocols due to its 100× faster start-up time. This fully integrated reference system enables a crystal-less Bluetooth Low Energy compliant radio in 65 nm CMOS and could provide on-board design convenience to end users.
ISSN:2327-1949
DOI:10.1109/FCS.2017.8088840