Custom Integrated Circuits Conference 

About: Custom Integrated Circuits Conference is an academic conference. The conference publishes majorly in the area(s): CMOS & Amplifier. Over the lifetime, 4833 publications have been published by the conference receiving 85201 citations.

Oscillator phase noise: a tutorial

Abstract: Linear time-invariant (LTI) phase noise theories provide important qualitative design insights but are limited in their quantitative predictive power. Part of the difficulty is that device noise undergoes multiple frequency translations to become oscillator phase noise. A quantitative understanding of this process requires abandoning the principle of time invariance assumed in most older theories of phase noise. Fortunately, the noise-to-phase transfer function of oscillators is still linear, despite the existence of the nonlinearities necessary for amplitude stabilization. In addition to providing a quantitative reconciliation between theory and measurement, the time-varying phase noise model presented in this tutorial identifies the importance of symmetry in suppressing the upconversion of 1/f noise into close-in phase noise, and provides an explicit appreciation of cyclostationary effects and AM-PM conversion. These insights allow a reinterpretation of why the Colpitts oscillator exhibits good performance, and suggest new oscillator topologies. Tuned LC and ring oscillator circuit examples are presented to reinforce the theoretical considerations developed. Simulation issues and the accommodation of amplitude noise are considered in appendixes.

A 220 mW 1 Gb/s 1024-bit rate-1/2 low density parity check code decoder

Abstract: A 1024-b, rate-1/2, soft decision low-density parity-check (LDPC) code decoder has been implemented that matches the coding gain of equivalent turbo codes. The decoder features a parallel architecture that supports a maximum throughput of 1 Gb/s while performing 64 decoder iterations. The parallel architecture enables rapid convergence in the decoding algorithm to be translated into low decoder switching activity resulting in a power dissipation of only 690 mW from a 1.5-V supply.

A 10 b, 20 Msample/s, 35 mW pipeline A/D converter

Abstract: ―This paper describes a 10 b, 20 Msample/s pipeline A/D converter implemented in 1.2 μm CMOS technology which achieves a power dissipation of 35 mW at full speed operation. Circuit techniques used to achieve this level of power dissipation include digital correction to allow the use of dynamic comparators, and optimum scaling of capacitor values through the pipeline. Also, to be compatible with low voltage mixed-signal system environments, a switched capacitor (SC) circuit in each pipeline stage is implemented and operated at 3.3 V with a new high-speed, low-voltage operational amplifier and charge pump circuits. Measured performance includes 0.6 LSB of INL, 59.1 dB of SNDR (Signal-to-Noise-plus-Distortion-Ratio) for 100 kHz input at 20 Msample/s. At Nyquist sampling (10 MHz input), SNDR is 55.0 dB. Differential input range is ± 1 V, and measured input referred RMS noise is 220 μV. The power dissipation at 1 MS/s is below 3 mW with 58 dB of SNDR.

New paradigm of predictive MOSFET and interconnect modeling for early circuit simulation

Abstract: A new paradigm of predictive MOSFET and interconnect modeling is introduced. This approach is developed to specifically address SPICE compatible parameters for future technology generations. For a given technology node, designers can use default values or directly input L/sub eff/, T/sub ok/, V/sub t/, R/sub dsw/ and interconnect dimensions to instantly obtain a BSIM3v3 customized model for early stages of circuit design and research. Models for 0.18 /spl mu/m and 0.13 /spl mu/m technology nodes with L/sub eff/ down to 70 nm are currently available on the web. Comparisons with published data and 2D simulations are used to verify this predictive technology model.

Physical processes of phase noise in differential LC oscillators

Abstract: There is an unprecedented interest among circuit designers today to obtain insight into the mechanisms of phase noise in LC oscillators. For only with this insight is it possible to optimize oscillator circuits using low-quality integrated resonators to comply with the exacting phase noise specifications of modern wireless systems. In this paper we concentrate on an understanding of the popular differential LC oscillator. We introduce simple models to capture the nonlinear processes that convert voltage or current thermal noise in resistors or transistors into phase noise in the oscillator. The analysis does not require hypothetical elements, such as limiters or amplitude control loops, to fully explain phase noise. A simple expression at the end accurately specifies thermally induced phase noise, and lends substance to Leeson's original hypothesis. Next, the upconversion of flicker noise into phase noise is traced to mechanisms first identified in the 1930's, but apparently since forgotten. Unlike thermally induced phase noise, which appears as phase modulation sidebands, flicker noise is shown to upconvert by bias-dependent frequency modulation. The results are validated against SpectreRF simulations and measurements on two differential CMOS oscillators tuned by resonators with very different Q's.