A Fast Settling Frequency-to-Voltage Converter with Separate Voltage Tracing Technique for FLLs

A novel switch-capacitor based frequency-to- voltage converter (FVC) featuring with fast settling speed is proposed in this paper. By utilizing the separate voltage tracing (SVT) technique instead of traditional charge redistribution mechanism, the successive approximation process is eliminated. Moreover, a separate tracing current is adopted to relieve the fading of tracing capability. Consequently, the tradeoff between the settling speed and the precision is released in the proposed FVC. Designed and fabricated in 0.18 μm CMOS process, the proposed FVC can settle within in 60 ns. The input frequency up to 316 MHz can be converted under 1.8 V supply with the power consumption of only 0.54 mW.