10-bit A/D converter soars to 2.2-GHz

San Jose, Calif. — Atmel Corp. claims to have developed the industry's fastest 10-bit analog-to-digital converter (A/D converter) with a clock frequency of 2.2 Gsamples/s.

The AT84AS008GL is pin-compatible with Atmel's TS83102G0BGL older 10-bit, 2 Gsamples/s A/D converter, allowing for seamless upgrades and providing a full 8 effective number of bits (ENOB) at 1.7 Gsamples/s in 1st Nyquist for high-speed digitization applications such as broadband test and measurement equipment, high-speed data acquisition, telecommunications and defense.

The AT84AS008GL is the latest in Atmel's family of Gigahertz 10-bit data converters, providing a new level of linear performance over 1st and 2nd Nyquist zones, while reducing power consumption and improving frequency spectral response.

By leveraging Atmel's expertise in fast A/D converter design and incorporating the latest advances in the company's data converter architectures, the A/D converter provides excellent dynamic performance of 55dB spurious-free dynamic range (SFDR) and 51dB signal-to-noise ratio (SNR) at 2.2 Gsamples/s in 1st Nyquist conditions.

Furthermore, the 3.3-GHz input bandwidth extends A/D converter operation well into the 2nd Nyquist zone with essentially flat performance: SNR remains at 48dB and SFDR at 55dB.

Interfacing the AT84AS008GL with FPGAs, DSPs, or ASICs is possible through a new Atmel companion demultiplexer chip, AT84CS001TP. It provides 10-bit, 2.2-GHz performance with 1:4 or 1:2 low-voltage differential signaling (LVDS) compatible demultiplexing ratios. The demultiplexer chip operates at data rates up to 550 Msamples/s.

“The AT84AS008GL is a step-ahead of the competition, being the first A/D converter available on the market to provide a guaranteed 2.2-GHz sampling rate, which is nearly 50 percent faster than the closest competitor,” said Andrew Benn, marketing manager for Atmel's Broadband Data Conversion product line.

In addition, the fast Fourier transform (FFT) spectral response remains very stable over temperature and clock frequency variations, allowing significant system performance enhancement through digital processing even under severe environmental conditions, Benn added.

The AT84AS008GL comes in a CBGA 152 ceramic package and operates over commercial and industrial temperature ranges. A military-grade version is planned for 2006. Samples are available now with production quantities slated for next month.

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Pricing is $1,100 each for the AT84AS008GL in 1,000-piece quantities.Click here for the AT84AS008GL data sheet.

Also sampling now, the AT84CS001TP demultiplexer chip is priced at $220.00 each in same quantities. Volume production will begin this month. Click here for the AT84CS001TP data sheet.

Atmel Corp. , 1-408-451-2855,

If I had to choose one word to describe Atmel's latest blazing A/D converter — I would say the word “booya” hits the nail on the head. I recently heard my nine-year-old son use this word. I wanted to make sure he wasn't swearing so I looked it up. According to an online urban dictionary, it's basically slang for, “bam!”, “in your face”, and “hell yeah”, all at the same time — a term that self congratulates the user.

The AT84AS008GL A/D converter is a low noise 2.2 Gsamples/s version of the company's predecessor chip — TS83102G0B (10-bit, 2 Gsamples/s A/D converter), which offers significant improvements in performance while retaining the same functions and I/O interface. The SNR shows a 10 dB improvement, leading to an ENOB of 8 bits at 1.7 Gsamples/s and 7.7 bits at 2.2 Gsamples/s in Nyquist conditions.

The improved performance and pin-to-pin compatibility with the TS83102G0B A/D converter give designers the ability to rapidly upgrade their existing boards or to design new systems with enhanced performance, without any thermal issue since the AT84AS008GL dissipates 10 percent less power than the TS83102G0B, Benn said.

Obviously, the higher the ENOB, the better. Atmel has managed to boost the ENOB from 7 in the previous device to 8 ENOB today, Benn said. Since the older and new devices are fully compatible, switching to the AT84AS008GL can improve the overall performance of the system since it's directly linked to the performance of a few essential components including the data converter. In a radar system, for instance, replacing the device can increase sensitivity, Benn said. Applications in the defense and high-end instrumentation (data acquisition boards) industries are always demanding the best performance, he said.

“The 8 ENOB at 1.7 Gsamples/s is attractive to designers in the instrumentation industry where precision is key,” said Susie Inouye, principal analyst of Databeans Inc. (Reno, Nev.) “The speed and dynamic performance enables more efficient designs in telecom and ATE. At these speeds and input frequencies, this A/D converter is targeting very specific and demanding applications,” she said.

Another benefit of using this A/D converter is that the FFT response throughout the 1st and 2nd Nyquist zones is now very clean and stable, allowing corrections with Look-Up Tables (LUTs), Benn said.

When you measure an A/D converter, you can find its imperfections. If you know what the imperfections are, and they don't change when you change the frequency of the system, you can use the LUT to correct them. If the response of the A/D converter is not stable, then you can't correct them. “With our A/D converter, the response is stable from DC to 2.2 GHz so you can always use the same LUT,” Benn said.

Typically, in a communications system, you receive a signal at a certain frequency. You may receive a signal through the antenna at 30 GHz, for instance. “Before putting this signal into the A/D converter though, you need to lower the frequency because the A/D converter usually only accepts signals up to 1 GHz or 2 GHz,” Benn said.

A key feature of this device is that it maintains high performance over both the 1st and 2nd Nyquist zones. “It's unusual to find a component that operates over both Nyquist zones,” according to Benn. If the device works well over both zones, it means the designer has a choice. The designer can give the A/D converter a signal between 0 and 2 GHz, instead of just between zero and 1 GHz (1st Nyquist zone). “This relaxes the constraints on the system because you don't have to lower the frequency of the antenna so much,” Benn said.

Current FPGA or similar devices in the marketplace can only handle signals from the A/D converter of roughly 500 Msamples/s, Benn said. This is why Atmel offers demultiplexer companion chips along with its A/D converter.

Atmel recently released a new demultiplexer chip, the AT84CS001TP, which is an improved version of its TS81102G0TP chip: it can handle signals up to 2.2 Gsamples/s, versus 1.5 Gsamples/s, while consuming 70 percent less power. “With this new demultiplexer chip you can make the most of the new 2.2 Gsps A/D converter and use it at full speed,” Benn said.

All of these product enhancements are made possible via the A/D converter's architecture. The device includes a front-end track and hold stage (T/H), followed by an analog encoding stage (analog quantizer), which outputs analog residues resulting from analog quantization. Successive banks of latches regenerate the analog residues into logical levels before entering an error correction circuitry and a resynchronization stage followed by 100Ω differential output buffers. To read more about the architecture, check out Page 2 of the data sheet (link with pricing) under “Functional Description.”

Click here to see a recent product review by senior technical editor Alex Mendelsohn of Pentek’s Model 6826 VME A/D Converter board. The board utilizes Atmel’s new A/D converter.

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