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Analog Noise Generator IC with Digitally-Programmable Colour
Team: Servando Espejo,
Manuel Delgado-Restituto and Angel Rodríguez-Vázquez
Date: 1989
| Physical Data |
- 3µ
m CMOS n-well, double poly, double metal
- 1440µ m
X 875µ
m (excluiding pads)
- 190 transistors
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Electrical Data |
- 5v@2.3mW
- 4v rail-to-rail output range@200kHz bandwidth
- 6 bit programmability per branch
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Design Technique: |
- Analog full-custom
- Switched-Capacitor circuits:
- Offset- and parasitics-insensitive.
- Two-stage OTAs with UGBs.
- Dummy switches.
- Hard threshold nonlinearity.
- Self-biased comparators
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Features and Applications: |
- Based on chaotic nonlinear finite-differences
equation.
- First worldwide monolithic realization
of controllable chaos.
- Inherent rail-to-rail analog noise amplitude.
- Inherent aperiodical random signals.
- Good high-level statistics.
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Noise sources are basic building blocks for
instrumentation and communication systems, as well as for dynamic testing.
White noise sources are also exploitable to generate sequences of random
numbers and for learning purposes in VLSI information processing systems
based on neural networks. Conventional approaches to generate random signals
use either physical sources of analog noise or nonlinear feedback digital
registers. Since the former obtains very low-amplitude noise, their practical
use requires amplification, which produces significant spurious correlations.
The latter obtains sequences where periodicity exists, although it is
usually exhibited after long repetition cycles.
This chip uses a new concept to generate
analog noise with intrinsic rail-to-rail amplitude and fully non-periodical
behavior. It realizes a parametric nonlinear finite-difference equation,
whose behavior becomes chaotic through proper
choice of the nonlinear function shape and the values of the parameter
vector P. The shape of the non-linearity and the values of the parameter
vector are controlled through an 6-bit digital word to shape the frequency
spectrum of the random signal provided by the chip. More details are available
in the following papers: [Delg92], [Rodr87], [Rodr91],
[Rodr92].
References:
- [Delg92] M. Delgado-Restituto, A. Rodríguez-Vázquez,
S. Espejo and J.L. Huertas: "A Chaotic Switched-Capacitor Circuit
for 1/f Noise Generation". IEEE Trans. Circuits and Systems, Vol.
39, pp. 325-328, April 1992.
- [Rodr87] A. Rodríguez-Vázquez,
J.L. Huertas, A. Rueda and B. Pérez-Verdú: "Chaos
from Switched-Capacitor Circuits: Discrete Maps". Proceedings of
the IEEE, Vol. 75, pp. 1090-1106, Aug. 1987.
- [Rodr91] A. Rodríguez-Vázquez,
M. Delgado-Restituto, S. Espejo and J.L. Huertas: "Switched-Capacitor
Broadband Noise Generator for CMOS VLSI". Electronics Letters,
Vol. 27, pp.1913-1915, October 1991.
- [Rodr92] A. Rodríguez-Vázquez,
S. Espejo, J.L. Huertas and J.D. Martín: "Analog Building
Blocks for Noise and Truly Random Number Generation in CMOS VLSI".
Proc. of the 1992 Solid-State Circuits Conference, ISBN 2-86332-087-4,
pp. 229-232, Frontieres, Sept. 1992.
Images List:
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