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BANGALORE: Analog Devices Inc. (NYSE: ADI), a global leader in
high-performance semiconductors for signal-processing applications,
today introduced a two-chip IF (intermediate frequency) receiver
solution that dramatically improves the data bandwidth and capacity
of next-generation, multi-carrier wireless base stations 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 pico-cell base stations with dramatically reduced
power consumption and physical volume.
Each radio channel can handle up to six carriers. The new VGA and
IF diversity receiver also increase automatic gain-control loop
performance by 100 times existing options, which improves base station
receiver sensitivity and dynamic range and ensures both weak and
strong incoming cell phone call signals are quickly and effectively
received and processed.
 The
AD8376 and AD6655 comprise the first two-chip dual-channel IF receiver
optimized to handle both the main and diversity receive paths simultaneously.
The combination of best-in-class performance, power consumption,
size and cost is ideally suited to meet the wider bandwidth and
multi-carrier 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 multi-carrier 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 50 dBm at 140 MHZ. This level of performance
and step resolution simplifies receiver automatic gain control (AGC),
and enables wideband multi-carrier radio platforms. A fine-step
AGC loop allows the designer to maximize the ADC’s dynamic
range, which is critical when handling either 3G or WiMAX multi-carrier
wideband input signals.
More about the AD8376 VGA
The AD8376 dual-channel VGA provides precise fine-gain-step adjustment
for digital radio receivers. The device features a bandwidth of
600 MHz, 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 +5volt supply, current consumption is also significantly
reduced.
More about the AD6655 IF Diversity Receiver
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 14-bit
ADC (analog-to-digital converter), at 150 MSPS (million samples
per second), followed by a DDC (digital down converter). The DDC
functionality includes a 32-bit 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 75 dB at 70 MHz, an improvement of 2.5
dB over the typical ADC. By integrating the DDC with the ADC, designers
realize 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 14-bit resolutions
with sample rates of 80 MSPS, 105 MSPS, 125 MSPS and 150 MSPS. 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.
Pricing and Availability
The AD8376 dual-channel digitally-controlled VGA is sampling now
with full production scheduled for June 2007. The AD8376 is priced
at $6.25 per unit in 1,000-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 1,000-piece
quantities and is housed in a 24-lead LFCSP. For more information,
visit www.analog.com/pr/AD8376.
The AD6653/5 IF diversity receivers are sampling now with full
production scheduled for June 2007. The 12-bit version, the AD6653,
is priced at $57.97 and the 14-bit at $97.50, both in 1,000-piece
quantities. Both devices are available in a 9 mm x 9 mm 64-lead
LFCSP. For more information, visit www.analog.com/pr/AD6655.
Analog Devices’ RF Expertise
Analog Devices’ RF ICs have the high-performance specifications—such
as temperature stability and high accuracy—that reduce component
count, decrease cost, and ease design challenges, thus enabling
new, highly desirable architectural changes to radio designs. Using
a unique combination of design skills, process technologies, and
system understanding, Analog Devices has a broad portfolio of RF
ICs, including complete chipsets and a full range of high-performance
RF function blocks. Among its extensive offerings are direct digital
synthesizers (DDS); phase-locked loop synthesizers (PLLs); detectors
and logarithmic operational amplifiers; fixed and variable-gain
amplifiers (VGAs); TruPwr™ RF power detectors; mixers, modulators,
and demodulators; integrated IF amplifiers; and the Othello®
family of single-chip transceivers for cellular terminals.
About Analog Devices
Innovation, performance, and excellence are the cultural pillars
on which Analog Devices has built one of the most long-standing,
high-growth companies within the technology sector. Acknowledged
industry-wide as the world leader in data conversion and signal
conditioning technology, Analog Devices serves over 60,000 customers
around the world, representing virtually all types of electronics
equipment. Celebrating more than 40 years as a leading global manufacturer
of high-performance integrated circuits used in analog and digital
signal processing applications, Analog Devices, Inc. is headquartered
in Norwood, Massachusetts, and employs approximately 8,900 people
worldwide. It has manufacturing facilities in Massachusetts, California,
North Carolina, Ireland, and the Philippines. Analog Devices' common
stock is listed on the New York Stock Exchange and ADI is included
in the S&P 500 Index.
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