This page provides links to publications and reports and a chronology of the fabricated chips which were designed in the Analog VLSI Systems Group in the Information Systems Laboratory at Stanford University, Electrical Engineering.
Examples of work carried out in this program are:
Imaging systems based on signal processing and A/D conversion at the pixel level.
An analog VLSI model of the cochlear mechanism.
An analog wavelet transform chip.
A few of my talks and papers on the subject of Analog VLSI Systems:
A Stanford Seminar from 1995: "Mathematical Engineering and VLSI Systems," (updated on 31 December 2001 to PDF with scalable fonts).
A paper on VLSI device and circuit modeling: "CMOS Device Modeling for Subthreshold Circuits," IEEE Trans. on Circ. and Sys II; Analog and Digital Signal Processing, vol. 39, no. 8, Aug. 92.
"A
VLSI Device Model for Analog Circuits." This second paper substantially
supersedes the IEEE paper. It is at present under revision for
possible publication, if I ever get around to resubmitting it. An
update was made on 5 May 2004. The changes in this update include several
clarifications
and updated Figures. There is an extended discussion of the
history of measurement of the band gap energy and its temperature dependence.
26 September 2004: minor update to correct Table of Contents.
In addition, the Octave/Matlab files which are discussed in the paper
are available in tar format. These files include the model as described in
the paper and example analysis and plotting routines. These routines generated
some of the plots shown in the paper. The code is old enough so that some
changes will be needed for them to function correctly when using current versions of
Octave or Matlab. The changes concern the plotting of the data.
A paper titled "The tanh Transformation" which describes some useful properties of the tanh function and indicates specifically how these properties can be useful in analog VLSI circuits.
Boyd Fowler's Ph.D. thesis: " CMOS Area Image Sensors with Pixel Level A/D Conversion"
Papers on wavelet transforms mainly by Tim Edwards, including our paper from ICNN2 1995, "An Analog Wavelet Transform Chip," (updated from PostScript to PDF on 20 July, 2002) and a paper written by Tim, "Discrete Wavelet Transforms: Theory and Implementation" (also updated from PostScript to PDF on 20 July, 2002) about the wavelet transform implementation on the Star Semiconductor SMP DSP chip. This implementation is of technical interest even though Star Semiconductor Inc. is no longer in business.
The versions of
Gemini 2.7.2 and
IRSIM 9.5 which we used under Redhat Linux 9
are available here. As far as we know, this is the latest version of Gemini. However,
Tim Edwards has made IRSIM 9.7 available, which is likely a better choice.
For many years we used a modified version of Magic 6.5.1 but it
is best to obtain a current version from
Cornell. Or, if you
want the latest, you could try
Tim Edwards current Magic site. Magic 7.4 (or 5) contains all the changes that we had
made. In particular, it contains the file locking mechanism, which supports multiple users
accessing the same design. We have moved to the latest 7.x version.
The OS/2 ports of Magic 6.5.1, Gemini 2.7.2 and IRSIM 9.5 have
been available
here. I have not
updated the distributions recently, and no longer know anyone who still uses OS/2.
The Table below lists the chips which have been fabricated through the MOSIS fabrication service
| Note | Chip Name | Fab date | MOSIS ID | Project Purpose | |
|---|---|---|---|---|---|
| (1) | SAS1 | 26-06-91 | N16ADN1 | cochlea, test transistors, filter | |
| SAS2 | 13-11-91 | N1BBEF1 | test-array, amps, pulse-freq circuits, floating-gates | ||
| SAS3A(cls1A) | 10-12-91 | N1CFDP1 | 392B Class Lab chip (Caltech) | ||
| SAS3B(cls1B) | 11-03-92 | N23SCV1 | 392B Class Lab chip (Stanford) | ||
| SAS4A | 08-04-92 | N24VEC1 | Two cochleas for directional sound | ||
| SAS4B | 08-04-92 | N24VDE1 | Correlator for cochleas | ||
| SAS6 | 26-08-92 | N28RAT1 | Model of stringed instrument and pulse-frequency circuits | ||
| SAS7 | 26-08-92 | N28RAW1 | Student test circuits and test oscillator | ||
| SAS8 | 18-11-92 | N2BIBQ1 | Transistor array for analysis of sources of device variation. | ||
| SAS9 | 16-12-92 | N2CPDG1 | Analog wavelet transform | ||
| (2) | SAS10 | 22-03-93 | N33DBQ1 | Single chip radio transmitter and test photodiodes. | |
| SAS11 | 28-04-93 | N34OEJ1 | Analog wavelet transform | ||
| (3) | SAS12 | 07-07-93 | N37FAD1 | Imaging circuit (64x64) | |
| SAS13 | 07-07-93 | N37GAB1 | Phase-modulated I/O interface | ||
| SAS14 | 14-07-93 | N37ECB1 | Concurrent implementation of sound localization. | ||
| SAS15 | 14-07-93 | N37EBU1 | Experimental phototransistors | ||
| SAS16 | 11-08-93 | N38JDA1 | Analog wavelet transform | ||
| SAS17 | 08-12-93 | N3CKAD | 41376 | Test circuits for imaging array | |
| SAS18 | 03-05-94 IBM | N45XAH | 42797 | Imaging test circuits (IBM) | |
| SAS19 | 03-05-94 IBM | N45XAF | 42771 | Class chip and tests (IBM) | |
| SAS20 | 11-05-94 IBM | N45XAE | 42857 | Imaging test circuits (IBM) | |
| (4) | SAS21 | 06-07-94 HP | N47HAQ | 43286 | Fast interconnect for FPGA's |
| SAS22 | 19-07-94 IBM | N47JAF | 43331 | Class chip and tests (IBM) | |
| SAS23 | 25-01-95 HP | N51UAM | 44980 | Imaging test circuits | |
| (5) | SAS24 | 25-01-95 HP | N51UAP | 44981 | async FPGA system |
| SAS25 | 30-01-95 HP | N52VAD | 45002 | Analog filters for auditory system | |
| SAS26 | 01-02-95 HP | N52VAE | 45016 | process noise measurements | |
| (5) | SAS27 | 14-02-95 HP | N52XAH | 45213 | async FPGA system |
| SAS28 | 01-03-95 HP | N53ZAK | 45279 | Analog filters for autitory system | |
| (5) | SAS29 | 15-03-95 HP | N53DAG | 45496 | another async FPGA array |
| SAS30 | 11-04-95 HP | N54FAH | 45733 | Analog filters for auditory system. | |
| (5) | SAS31a | 24-05-95 HP | N55NAF | 46036 | async FPGA system |
| SAS31b | 21-06-95 HP | N56QAP | 46320 | 128x128 imaging array | |
| SAS32 | 08-05-96 HP | N65WAA | 48813 | auditory processor | |
| SAS33 | 12-06-96 HP | N66DAD | 49180 | auditory processor | |
| SAS34 | 09-12-96 HP | N6CLAM | 50733 | auditory processor | |
| SAS35 | 27-03-97 HP | N73HAM | 51656 | auditory processor | |
| (6) | IMHP01 | 11-08-97 HP | N77EAW | 52509 | 640x512 imaging array |
Notes on chips of special interest:
This chip produced a paper on subthreshold device modeling, and it produced a working model of the cochlea which resulted in a Ph.D. thesis by Neal Bhadkamkar.
This chip contains a very small, very low-cost single chip radio transmitter (implemented by Boyd Fowler) which could do lots of useful things around the home, or elsewhere.
This chip is a 64x64 phototransistor array which contains, at each pixel, analog light measuring circuits, sigma-delta modulator, and A/D conversion. It has many performance and cost advantages over CDDs. This is Boyd Fowler's Ph.D. work. It has been reported on in the ISSCC Conference 94, and the Ph.D. has been awarded.
This chip demonstrates a major performance improvement for the interconnect lines used in FPGA structures. It is the Ph.D. thesis work of Ivo Dobbelaere. It has been reported on in the ISSCC Conference 95, and the Ph.D. has been awarded.
This is another Ph.D. project by Dana How which implements a high-performance asynchronous FPGA system. His Ph.D. has been awarded.
This chip was fabricated on the 0.35um process. It contains approximately 1.3 million transistors. The chip is fully functional and will be the subject of a number of Ph.D.'s and publications. Check out Abbas El Gamal's Group.
As time permits we will add more material to this page, and provide more links to reports and publications.