Analysis and simulation of substrate coupling in integrated circuits

A technique is presented which allows efficient calculation of substrate-coupling macromodels in integrated circuits. the technique can be used to calculate node-to-node resistances or impedances in substrate models. Examples of the technique applied to several test structures are presented.     

Modeling and analysis of substrate coupling in integrated circuits

This paper describes a fast and accurate simulator for characterizing the effects of substrate coupling on integrated-circuit performance. The technique uses the electrostatic Green function of the substrate medium and the fast Fourier transform algorithm. It is demonstrated that this technique is suitable for optimization of layout for minimization of substrate coupling. Analysis of substrate coupling in different types of substrates and the utility of guard rings in different types of substrates is also discussed. Experimental verification of the models is presented     

A direct-conversion receiver for the 3G WCDMA standard

A highly integrated direct-conversion receiver that satisfies requirements of the third-generation wide-band code-division multiple-access mobile phone standard is described. The receiver integrated circuit includes the front-end low-noise amplifier, downconversion mixers, baseband variable-gain amplifiers, channel-select filters, and the frequency synthesizer. External components are limited to matching elements required for the low-noise amplifier and the mixers and two passive band-select filters. The receiver is implemented in a SiGe BiCMOS process and consumes a total current of 46 mA from a 2.7-V supply.     

Recursive Receiver Down-Converters With Multiband Feedback and Gain-Reuse

Receiver down-converter topologies are presented that provide simultaneous frequency conversion and baseband amplification within a mixer, in order to reduce power dissipation for a given dynamic range. The down-converted IF output of a mixer is reapplied to its input stage in a recursive manner, which significantly enhances the conversion gain, with current requirement determined primarily by the input transconductor of the mixer. Two down-converter topologies based on this technique are presented. One topology utilizes common-source NMOS devices as the RF input stage of the mixer, and reuses their transconductance for providing baseband gain. The second topology utilizes differential pairs as the RF input stage, and employs the transconductance of the tail current-source devices for baseband gain. The designs are implemented in a 0.13 mum CMOS technology and achieve peak conversion gains of 50 dB and 56 dB, with single side-band noise figures of 12.7 dB and 9.4 dB, and OIP3 values of 8 and 11 , respectively. They operate at a nominal supply of 1.2 V with bias current of 2.9 mA and 2.1 mA, respectively. The active die area is less than 0.1 mm for each design. Noise and linearity performance of the down-converters is analyzed, and the potential for enhancement of IIP3 through cancellation of nonlinear products is discussed.     

Built-in Self Test of RF Subsystems with Integrated Detectors

This paper describes a built-in self test technique for RF subsystems, using low-overhead on-chip detectors to calculate circuit specifications. A novel on-chip amplitude detector has been designed and optimized for RF circuit specification test. The detector has small area overhead with a low-frequency output. A test chip was fabricated in a commercial 0.18 μm CMOS process. By using on-chip detectors in a loopback setup, both the system performance and specifications of the individual components can be accurately measured. Measurements show accurate prediction of system and component specifications.     

Feedforward Interference Cancellation in Radio Receiver Front-Ends

An interference cancellation technique is described for improving the dynamic range of receivers. A feedforward approach is used to attenuate large interferers before the down-conversion mixer in a receiver. This is accomplished with no measurable impact on the in-band noise performance. Techniques to cancel interference within a narrowband and also in multiple bands are described. Simulation results and measurements from a discrete prototype system are used to validate the approach.