Product category:
Analogue and Mixed Signal ICs
News Release from: Analog Devices | Subject: AD9445
Edited by the Electronicstalk Editorial
Team on 11 May 2005
High-dynamic-range ADC captures weaker
signals
Analog Devices continues to innovate in the field of data conversion by introducing a high-speed analogue-to-digital converter (ADC) that extends key converter specifications to new levels.
Analog Devices continues to innovate in the field of data conversion by introducing a high-speed analogue-to-digital convertor (ADC) that extends key convertor specifications to new levels The AD9445 is the first 14bit, 125Msample/s ADC to achieve a spurious-free dynamic range (SFDR) above 80dBc and a signal-to-noise ratio (SNR) of 72.5dBfs at input frequencies up to 300MHz, better than competing solutions by a full 10 and 4dB, respectively
This article was originally published on Electronicstalk on 2 Jul 2008 at 8.00am (UK)
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A convertor with high SFDR can capture weak signals in the frequency band of interest, despite the presence of strong, interfering signals.
The industry-leading SNR characteristics of the AD9445 enable wireless infrastructure equipment designers to improve cellular basestation receivers by offering lower overall system noise at higher intermediate frequencies, which translates to expanded cellular coverage and fewer dropped calls.
Moreover, the combination of high input frequency and high sampling rate eliminates a frequency down-conversion step before the ADC and eases the analogue filtering burden.
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Both of these elements offer significant cost savings to the wireless system designer.
"The performance of a convertor is measured in many dimensions, and in wireless infrastructure SNR and SFDR are key", said Kevin Kattmann, Product Line Director in the High Speed Convertor Group at Analog Devices.
"Only by pushing the SNR, SFDR and sample rate of the AD9445 were we able to unlock a simplified analogue filter topography that increases overall basestation receiver performance while reducing cost, time and complexity".
The high SFDR of the AD9445 ADC expands the dynamic range of wireless basestation receivers, while improving quality of service and lowering component count and cost.
The AD9445 also achieves an aperture jitter of 60fs, compared with the 250 to 300fs aperture jitter of competing ADCs, which is critical to maintaining SNR at high input frequencies.
Aperture jitter is the sample-to-sample variation in aperture delay and a major contributor to overall system signal degradation.
The AD9445 extends ADI's family of high-speed, high-resolution ADCs that offer higher sample rates, ease of use and improved dynamic performance.
This includes the recently introduced 14bit, 80Msample/s AD9444 and the 16bit, 100Msample/s AD9446.
In addition to delivering greater than 80dBc SFDR at a 300MHz input frequency and 85dBc SFDR at 225MHz, the AD9445 provides high DC accuracy, with typical differential nonlinearity (DNL) of +/-0.2LSB and integral nonlinearity (INL) of +/-1.0LSB.
The ADC also features a flexible input range up to 3.2V peak-peak, allowing the user to achieve SNR performance as high as 78dBfs, a full 6dB better than any ADC of this class, while maintaining the state-of-the-art SFDR and IF sampling performance.
The AD9445 also has an on-chip reference and track-and-hold, and parallel low-voltage differential signalling (LVDS) outputs to ease the interface to digital down-convertors.
The AD9445 is optimised for multicarrier, multimode receivers such as those found in next-generation cellular infrastructure equipment.
The device's high-resolution and outstanding performance also makes it suitable for antenna array positioning, power amplifier linearisation, broadband wireless, radar and infrared imaging, medical imaging, communications instrumentation, and software-defined and cognitive radios.
Virtually every cellular phone call made in the world today passes through ADI chips used throughout the radio transceiver design.
The high IF signal is digitised by the AD9445, and the LVDS output interfaces seamlessly with the LVDS input of the AD6636, a multichannel wideband digital down-convertor, which in turn is optimised for Analog Devices' TigerSHARC digital signal processor.
The AD9445 is an ideal companion to Analog Devices' AD9779 TxDAC+ digital-to-analogue convertor and ADI's family of VersaCOMM digital down- and up-convertors.
The AD9445-125 and AD9445-105 ADCs are sampling now in Pb-free, 100-lead TQFPEP (thin quad flat pack exposed paddle) packages with production quantities available in September 2005.
Pricing for the AD9445-125 and AD9445-105 is $59.50 and $49.30, respectively, in 1000-unit quantities.
The devices are supported by two evaluation boards and a behavioural model that can be used with Analog Devices' ADIsimADC modelling software.
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