high-Q Passives Research Articles

Fully integrated 2.2-mW CMOS front end for a 900-MHz wireless receiver

Low power consumption is the most important concern for integrated wireless devices. This paper illustrates low-power design principles in the CMOS context. They entail seeking strategic combinations of high-quality off-chip passives with RF integrated circuits and searching for better architectures in wireless receivers to low power. The principles are illustrated with a fully integrated 2.2-mW 1.2-V front end for 900-MHz receiver, fabricated in 0.35-/spl mu/m CMOS.

A 1.9-GHz DECT CMOS power amplifier with fully integrated multilayer LTCC passives

We present the first demonstration of a CMOS power amplifier (PA) utilizing fully integrated multilayer low-temperature co-fired ceramic (LTCC) high-Q passives for 1.9-GHz digital European cordless telecommunications (DECT) applications. The inductor and capacitor library were built in a multilayer LTCC board using a compact topology. An inductor Q-factor as high as 100 with a self-resonant frequency (SRF) as high as 8 GHz was demonstrated. Measured results of the CMOS-LTCC PA show good agreement with the simulated results exhibiting 48% power added efficiency, 26-dBm output power and 17-dB gain at 1.9 GHz with a 3.3-V drain supply voltage. This result is the first significant step toward a compact DECT transceiver module development utilizing fully integrated multilayer LTCC passives and a standard CMOS technology.

Feasibility of 0.18 μm SOI CMOS technology using hybrid trench isolation with high resistivity substrate for embedded RF/analog applications

A 0.18 /spl mu/m silicon on insulator (SOI) complementary metal-oxide semiconductor (CMOS) technology using hybrid trench isolation with high resistivity substrate is proposed and its feasibility for embedded RF/analog applications is demonstrated. The hybrid trench isolation is a combination of partial trench isolation and full trench isolation. In the partial trench isolation region, a part of the SOI layer remains under the field oxide so as to provide scalable body-tied SOI metal-oxide-semiconductor field-effect transistors (MOSFETs), while in the full trench isolation region, the whole of the SOI layer is replaced by the field oxide so as to provide high quality passives. It is demonstrated that this technology improves the maximum oscillation frequency and the minimum noise figure of the MOSFET and the Q-factor of the inductor, compared with bulk technology. Moreover, it is verified that the partial-trench-isolated body-tied structure suppresses the floating body effect of SOI devices for RF/analog applications and thus guarantees low-noise characteristics, stability, linearity, and reliability. It is concluded that this technology will be one of the key technologies for supporting the evolution of wireless communications.

A 3-V 4-GHz nMOS voltage-controlled oscillator with integrated resonator

There is increasing interest in implementing the key components of radio transceivers in mature silicon technologies. Submicron CMOS technology combined with low-parasitic on-chip passives is emerging as a strong candidate to implement many of these components that traditionally have been realized using GaAs. Fully-monolithic voltage-controlled oscillators (VCOs) present many challenges to any technology since they require low-parasitic high-quality passives for acceptable tuning range and phase noise levels, and low-power active devices at microwave frequencies. A 1.8 GHz CMOS VCO with a 4.5% tuning range is not fully monolithic, as it requires bonding wires as inductive elements in the tank circuit. Fully-integrated LC resonators offer the advantages of low cost and reduced sensitivity to packaging parasitics at the price of lower resonator Q values due to the losses in on-chip spiral inductors and varactor diodes. The authors present a fully-monolithic VCO based on an nMOS gain stage and an integrated tunable resonator operating at 4 GHz with a 9% tuning range. The technology is a 5-level metal 0.5 /spl mu/m BiCMOS process (BiCMOS4S+). No bipolar devices are used in the active circuitry.