Mark Cloutier

A 4-dB NF GPS receiver front-end with AGC and 2-b A/D

A dual-IF GPS receiver front-end integrates all the active circuitry to down-convert, amplify and digitize the 1,575.42 GHz L1 signal. The chip includes 3 dB NF LNA, 38 dB image reject mixer, VCO with integrated LC tank and varactor, PLL synthesizer, 55-dB range AGC with charge-pump control, 2-b A/D, crystal oscillator and TTL-compatible buffers. The receiver noise figure is 4 dB and maximum gain is 120 dB with a power consumption of 49 mA at 3 V supply. The AGC and 2-b A/D offer better SNR and significantly better blocking performance than the commonly used 1-b quantizers.

Analysis and measurements of EM and substrate coupling effects in common RF integrated circuits

An investigation of coupling between inductors and resonators fabricated in Si substrates is presented and the effects on RF systems and components is discussed. EM simulators (e.g., Agilent Momentum) provide accurate near field analysis of coupling in lossy and complex silicon substrates. Measurements verify theory and a novel experimental technique to measure inductor and resonator coupling makes use of injection-lockable bipolar oscillators. The experiment is fast, accurate, and unique in that no matching, probe de-embedding, or calibration is necessary as the ratio of two on-chip signals is measured to yield the results. As an example, accounting for inductor coupling in a 4.7 GHz LNA reduces the amplifiers gain from 22 dB to 18 dB.

Calibration-free on-chip inductor coupling experiment with injection-lockable VCOs

A novel experiment is presented which makes use of injection-lockable bipolar oscillators to measure on-chip coupling between integrated inductors. The experiment is fast, accurate and unique In that no matching, probe de-embedding or calibration is necessary as the ratio of two on-chip signals is measured to yield the results. Theoretical and simulated models of injectionlocked oscillators and inductor coupling are discussed and compared to results measured using the test chip to Validate the experiment. Results indicate about -55 dB of Coupling between two inductors spaced 175 pm apart. K e p m d Coupling Circuits, Electromagnetic Coupling, Inductors, Injection Locked Oscillators.