A 2.4-GHz frequency synthesizer based on process and temperature compensated ring ILFD
In this paper, a 2.4-GHz frequency synthesizer incorporating a ring-oscillator based process and temperature compensated injection-locked frequency divider (ILFD) is proposed. The synthesizer is implemented in a 0.18-mu m standard complementary metal-oxide semiconductor process with a chip area of 3 mm x 3 mm plus the off-chip capacitors for loop filter. With an LC oscillator, the output frequency can be tuned from 2.057 to 2.652 GHz, while the settling time is around 36 mu s with a loop bandwidth of 60 kHz. Measurements are performed across six different chips to study the circuit performance due to process variation. The worst-case total power consumption is measured to be 2.2 mW with a power supply of 1.8 V. The ILFD block is also tested separately and the test results show a wide locking range of 1.4 GHz over all the process corners and a temperature range from 0 to 80 A degrees C.
frequency synthesizer temperature compensated ilfd injection-locked ism band pll process compensated