Tuesday, March 30, 2010

Graphene as photodetector

At EETimes: "IBM demos graphene optical link".
The vertical-incidence metal-graphene-metal photodetector achieved 6.1 milliamps per watt at the communications wavelength of 1.55 microns, but was shown to be useful over a very wide bandwidth of 300 nanometers to 6 microns

Wednesday, March 24, 2010

Tuesday, March 23, 2010

imec's EEG 'thought-to-text' cap

As my head appears in the official press release (yes, that's me with the funny cap), here is a link to the news item at EETimes. If interested, here's a video of the procedure with me writing my name with the device.

Note: I was only a test subject. I am not involved in the actual development.

Update: More videos here.

Thursday, March 18, 2010

Wednesday, March 17, 2010

Measuring 18 bit DAC performance

Bill Schweber discusses the issues with new components giving 18 and even 20 bit performance. Of particular interest is the reference to this application note at Linear Technology: "1ppm Settling Time Measurement for a Monolithic 18-Bit DAC. When Does the Last Angel Stop Dancing on a Speeding Pinhead?"

Tuesday, March 16, 2010

Paper watch: Compressive Sensing

Compressive sensing/sampling is a subject gaining presence in the media (recent article at Wired). There is an extremely useful blog following all kind of developments in this area: Nuit Blanche.

And the latest issue of the IEEE Selected Topics in Signal Processing is fully devoted to it.

Paper watch: Image sensors and noise

(Apologies to those behind pay walls for the papers)

Two related papers on image sensors and noise.

* "Correction of dark current in consumer cameras"
A study of dark current in digital imagers in digital single-lens reflex (DSLR) and compact consumer-grade digital cameras is presented. Dark current is shown to vary with temperature, exposure time, and ISO setting. Further, dark current is shown to increase in successive images during a series of images. DSLR and compact consumer cameras are often designed such that they are contained within a densely packed camera body, and therefore the digital imagers within the camera frame are prone to heat generated by the sensor as well as nearby elements within the camera body. It is the scope of this work to characterize the dark current in such cameras and to show that the dark current, in part due to heat generated by the camera itself, can be corrected by using hot pixels on the imager. This method generates computed dark frames based on the dark current indicator value of the hottest pixels on the chip. We compare this method to standard methods of dark current correction.

* "Is Denoising Dead?"
Image denoising has been a well studied problem in the field of image processing. Yet researchers continue to focus attention on it to better the current state-of-the-art. Recently proposed methods take different approaches to the problem and yet their denoising performances are comparable. A pertinent question then to ask is whether there is a theoretical limit to denoising performance and, more importantly, are we there yet? As camera manufacturers continue to pack increasing numbers of pixels per unit area, an increase in noise sensitivity manifests itself in the form of a noisier image. We study the performance bounds for the image denoising problem. Our work in this paper estimates a lower bound on the mean squared error of the denoised result and compares the performance of current state-of-the-art denoising methods with this bound. We show that despite the phenomenal recent progress in the quality of denoising algorithms, some room for improvement still remains for a wide class of general images, and at certain signal-to-noise levels. Therefore, image denoising is not dead—yet.

IEEEXplore watch: Charge Pump Overview

(Apologies to those behind the pay-wall)

* "Charge Pump Circuits: An Overview on Design Strategies and Topologies"
Due to the continuous power supply reduction, charge pumps circuits are widely used in integrated circuits (ICs) devoted to several kind of applications such as smart power, nonvolatile memories, switched capacitor circuits, operational amplifiers, voltage regulators, SRAMs, LCD drivers, piezoelectric actuators, RF antenna switch controllers, etc. The main focus of this tutorial manuscript is to provide a deep understanding of the charge pumps behavior, to present useful models and key parameters and to organically and in details discuss the optimized design strategies. Finally, an overview of the main different topologies is also included.

Thursday, March 11, 2010

Overview of gate first/gate last technologies

At Semiconductor International: "Gate First, or Gate Last: Technologists Debate High-k"
As high-k rolls out beyond Intel Corp. to both mobile and high-performance applications, the industry now faces a divided landscape. Intel and Taiwan Semiconductor Manufacturing Co. Ltd. (TSMC, Hsinchu, Taiwan) — the largest MPU provider and pure-play foundry, respectively — are backing the replacement metal gate (RMG) or gate-last approach. Their competitors — Advanced Micro Devices Inc. (AMD, Sunnyvale, Calif.), GlobalFoundries Inc. (Sunnyvale, Calif.), IBM Corp. (Armonk, N.Y.), and other members of the Fishkill Alliance — are using the gate-first approach, at least for the 28 nm node. United Microelectronics Corp. (UMC, Hsinchu, Taiwan) said it will use a hybrid approach employing a gate-last method for the more-difficult PMOS transistor.

TI's own free analog simulator

I don't think it can steal users from the wonderful (and also free) LTSpice, but here is TINA.

MEMs relays as logic gates

Interesting post at Coventor's blog.

Graphene, is there something you can't do?

Graphene for electrodes in LEDs:
Today's organic displays use inorganic ITO for the transparent electrodes that turn pixels on and off, but the material is costly and in short supply because it is also used in LCD flat-panel manufacture. Graphene could cut costs more than a hundredfold, according to the Stanford researchers.
Graphene as support film for microscopy:
Graphene is a single atomic layer of carbon atoms tightly packed in a two-dimensional honeycomb lattice. This novel material is atomically thin, chemically inert, consists of light atoms, and possesses a highly ordered structure. Graphene is electrically and thermally conductive, and is the strongest material ever measured. These remarkable properties make graphene the ideal support film for electron microscopy.

Wednesday, March 10, 2010

Innovation in FPGAs

Tierlogic announced today their new approach for FPGAs:
The TierLogic chip uses nine layers of metal which hold the core logic array, over which the configuration SRAM transistors are held in an amorphous silicon TFT layer on top of the metal layers. The TFT layer is currently made using 0.18 micron technology and is scalable.
"Since 2003 we've been, filing patents and working on process technology", says Hollingworth, "we've 50 patents granted and 20 pending. There are some wide patents, e.g. 'Any kind of 3D structure connected with programmable circuits'. The patents cover new forms of transistor. We had to design a process technology, not just a chip. No one has done majority carrier devices in TFTs before."
UPDATE: Ron Wilson expands.