TY - JOUR
T1 - A Fast Startup CMOS Crystal Oscillator Using Two-Step Injection
AU - Megawer, Karim M.
AU - Pal, Nilanjan
AU - Elkholy, Ahmed
AU - Ahmed, Mostafa Gamal
AU - Khashaba, Amr
AU - Griffith, Danielle
AU - Hanumolu, Pavan Kumar
N1 - Publisher Copyright:
© 2019 IEEE.
PY - 2019/12
Y1 - 2019/12
N2 - Fast startup crystal oscillators (XOs) are needed in heavily duty-cycled communication systems for implementing aggressive dynamic power management schemes. This article presents the ways to improve startup time of XOs. Using a two-step injection technique in a three-step process, the proposed technique reduces the XO startup time to within 1.5 × the theoretical minimum. By solving the differential equation governing crystal resonator under injection for arbitrary injection frequency, the behavior of energy build-up inside a crystal resonator is analyzed and used to determine optimum injection time as a function of the desired XO steady-state amplitude and injection frequency error. Bounds on tolerable injection frequency error to guarantee the existence of optimal timing are provided. Fabricated in a 65-nm CMOS process, the proposed 54-MHz fast startup XO occupies an active area of 0.075 mm2 and achieves a startup time of less than 20 μs across a temperature range of -40 °C to 85 °C while consuming a startup energy of 34.9 nJ and operating from a 1.0-V supply.
AB - Fast startup crystal oscillators (XOs) are needed in heavily duty-cycled communication systems for implementing aggressive dynamic power management schemes. This article presents the ways to improve startup time of XOs. Using a two-step injection technique in a three-step process, the proposed technique reduces the XO startup time to within 1.5 × the theoretical minimum. By solving the differential equation governing crystal resonator under injection for arbitrary injection frequency, the behavior of energy build-up inside a crystal resonator is analyzed and used to determine optimum injection time as a function of the desired XO steady-state amplitude and injection frequency error. Bounds on tolerable injection frequency error to guarantee the existence of optimal timing are provided. Fabricated in a 65-nm CMOS process, the proposed 54-MHz fast startup XO occupies an active area of 0.075 mm2 and achieves a startup time of less than 20 μs across a temperature range of -40 °C to 85 °C while consuming a startup energy of 34.9 nJ and operating from a 1.0-V supply.
KW - Crystal oscillator (XO)
KW - digitally controlled oscillator (DCO)
KW - injection
KW - ring oscillator (RO)
KW - startup time
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U2 - 10.1109/JSSC.2019.2936296
DO - 10.1109/JSSC.2019.2936296
M3 - Article
AN - SCOPUS:85072518856
SN - 0018-9200
VL - 54
SP - 3257
EP - 3268
JO - IEEE Journal of Solid-State Circuits
JF - IEEE Journal of Solid-State Circuits
IS - 12
M1 - 8827914
ER -