Product category:
Communications ICs (Wireless)
News Release from: Analog Devices | Subject: AD8376 and AD6655 chipset
Edited by the Electronicstalk Editorial
Team on 14 March 2007
Chipset boosts basestation receiver
bandwidth
Two-chip IF receiver improves the data bandwidth and capacity of next-generation multicarrier wireless basestations compatible with emerging 3G cellular transmission standards.
Analog Devices has introduced a two-chip IF (intermediate frequency) receiver solution that dramatically improves the data bandwidth and capacity of next-generation, multicarrier wireless basestations compatible with emerging 3G cellular transmission standards Analog Devices' dual-channel AD8376 VGA (variable gain amplifier) and AD6655 IF diversity receiver solution replaces 48 discrete components, enabling 3G micro- and picocell basestations with dramatically reduced power consumption and physical volume
This article was originally published on Electronicstalk on 14 Sep 2001 at 8.00am (UK)
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The new VGA and IF diversity receiver also increase automatic gain-control loop performance by 100x existing options, which improves basestation receiver sensitivity and dynamic range and ensures both weak and strong incoming cellphone call signals are quickly and effectively received and processed.
The AD8376 and AD6655 comprise the first two-chip dual-channel IF receiver optimised to handle both the main and diversity receive paths simultaneously.
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The combination of best-in-class performance, power consumption, size and cost is ideally suited to meet the wider bandwidth and multicarrier signal processing demands of today's wireless infrastructure equipment, while supporting emerging 3G and 2.5G mobile phone communications standards such as CDMA2000, UMTS and TD-SCDMA, as well as WiMAX.
"As the industry migrates from voice-centric services and embraces feature-rich multimedia content, wireless infrastructure designers need devices that support the higher data bandwidths within the next-generation of mobile communications platforms", said Peter Real, Product Line Director, RF and Networking Components, Analog Devices.
"To help address this need, ADI developed the industry's highest linearity digital VGA and the fastest IF diversity receiver, which when combined, not only reduce component count, but bring complex multicarrier wideband digital receivers into mainstream production".
The AD8376 is the first digitally controlled VGA that enables 1dB gain-step resolution at the highest IFs.
The device offers the industry's best linearity of OIP3 50dBm at 140MHz.
This level of performance and step resolution simplifies receiver automatic gain control (AGC), and enables wideband multicarrier radio platforms.
A fine-step AGC loop allows the designer to maximise the ADC's dynamic range, which is critical when handling either 3G or WiMAX multicarrier wideband input signals.
The AD8376 dual-channel VGA provides precise fine-gain-step adjustment for digital radio receivers.
The device features a bandwidth of 600MHz, supporting high IF sampling receiver architectures within cellular and broadband WiMAX receivers.
An independent 5-pin digital interface allows the user to take advantage of a 24dB gain range and 1dB gain-step resolution.
The AD8376 is designed to replace discrete attenuator and IF amplifiers, offering considerable board and package density savings.
With 50dBm output IP3 on 130mA of quiescent current on a +5V supply, current consumption is also significantly reduced.
The AD6655 integrates many of the functions required for diversity receive path in a single device, including an ultra-low-latency peak detector and an RMS signal power monitor that can be used in conjunction with the AD8376 and logic to form a flexible AGC.
In addition, the AD6655 includes the industry's fastest 14bit ADC (analogue-to-digital convertor), at 150Msample/s, followed by a DDC (digital down convertor).
The DDC functionality includes a 32bit NCO (numerically controlled oscillator), a decimating half-band filter and an output FIR (finite-impulse response) filter.
Together, these provide an effective bandpass filtering function and reduce the output rate, which yields an SNR (signal-to-noise ratio) of 75dB at 70MHz, an improvement of 2.5dB over the typical ADC.
By integrating the DDC with the ADC, designers realise a significant reduction in board space while eliminating the high-speed interconnect problems usually found on system boards when the devices are implemented separately.
The AD6655 is offered in both 12- (AD6653) and 14bit resolutions with sample rates of 80, 105, 125 and 150Msample/s.
For applications that require only the dual-ADC function without the DDC, the recently-announced AD9640 is pin compatible and includes signal monitor, level detection, and 1-to-8 clock divider.
The AD8376 dual-channel digitally controlled VGA is sampling now with full production scheduled for June 2007.
The AD8376 is priced at US $6.25 per unit in 1000-piece quantities and is housed in a 32-lead LFCSP (lead-frame chip-scale package).
A single-channel version, the AD8375, is sampling now with full production also scheduled for June 2007.
The AD8375 is priced at $4.25 per unit in 1000-piece quantities and is housed in a 24-lead LFCSP.
The AD6653/5 IF diversity receivers are sampling now with full production scheduled for June 2007.
The 12bit version, the AD6653, is priced at $57.97 and the 14bit at $97.50, both in 1000-piece quantities.
Both devices are available in 9 x 9mm 64-lead LFCSPs.
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