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Compact Analog White Noise Generator IC
Team: Manuel Delgado-Restituto and
Angel Rodríguez-Vázquez
Date: 1994
| Physical Data |
- 1.6µ
m CMOS n-well, single poly, double metal.
- 400µ m x 240µ m.
- 26 transistors.
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Electrical Data |
- Current-mode operation.
- 3v@50µ A current rails@1.8mW.
- Analog current and digital voltage output.
- 40µ A rail-to-rail output range@500khz
bandwidth.
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Design Technique: |
- Analog full-custom.
- Switched-Current circuits:
- Self-biased cascode current mirrors.
- Dummy switches.
- Current sensing circuit with 10pAs detection
capability.
- Compensation of loading errors through
boosted current mirror nodes.
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Features and Applications: |
- Based on Bernoulli discrete map.
- Inherent rail-to-rail analog noise amplitude.
- Inherent non-periodical random signals.
- Highly flat power spectrum.
- Good high-level statistics.
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This circuit uses the same principle as the
previously-mentioned analog noise generator with digitally-programmable
color. However in this new chip the noise color cannot be externally programmed,
but remains white. This fixed functionality results in much more compact
physical realization. Another significant difference is found in the circuit
design technique; the other uses switched-capacitor circuits that operate
in voltage mode, while the new one uses switched-current circuits that
operate in current-mode. Consequently the former requires capacitors as
design primitives -- better suited for double-polysilicon technologies,
while the latter requires only MOS transistors -- fully compatible with
the standard single-poly VLSI technology. Additionally, this chip features
better speed/power than the previous one -- a consequence of the use of
a current-mode design technique.
The chip realizes the following discrete-time equation,
in current domain, and incorporates an innovative
CMOS circuit design strategy to realize current-mode highly accurate PWL
characteristics.
More details are available in the following
papers:
References:
- [Delg93] M. Delgado-Restituto,
F. Medeiro and A. Rodríguez-Vázquez: "Nonlinear Switched-Current
CMOS IC for Random Signal Generation". Electronics Letters, Vol.
29, pp. 2190-2191, December 1993.
- [Espe94] S. Espejo, R. Domínguez-Castro,
F. Medeiro and A. Rodríguez-Vázquez: "Tunable Feedthrough
Cancellation in Switched-Current Circuits". Electronics Letters,
Vol. 30, pp. 1912-1914, November 1994.
- [Rodr95] A. Rodríguez-Vázquez,
R. Domínguez-Castro, F. Medeiro and M. Delgado-Restituto: "High-Resolution
Current Comparators: Design and Applications to Current-Mode Function
Generation". Analog Integrated Circuits and Signal Processing,
Vol. 7, 1995 (to appear)
Images List:
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