Differential amp drives for wireless

Analog Devices claims to have developed the first single-chip low-distortion fully differential amplifier able to drive high-resolution ADCs at high speed.

Analog Devices claims to have developed the first single-chip, low-distortion, fully differential amplifier able to drive high-resolution (12-14bit) ADCs at high speed (70MHz) - a critical requirement for use in next generation wireless infrastructure equipment.

The AD8351 also supports 10bit distortion performance at 240MHz making it equally ideal for test equipment.

Analog Devices achieved these previously unattained performance levels by using the third generation of its proprietary XFCB and silicon on insulator manufacturing processes.

The result is a single chip that prevents signal bottlenecks at the ADC, making it an ideal solution for a broad range of applications, including differential ADC drivers, IF sampling receivers, RF/IF gain blocks, SAW filter interfacing, single-ended to differential conversion and instrumentation.

"The move to higher IF sampling radio architectures for 3G Universal Mobile Telecommunications System, CDMA 2000 systems and associated instrumentation and test equipment means that our industry must find an acceptable balance between performance and power", said Lew Counts, Vice President, Advanced Linear Products at Analog Devices.

"The AD8351 differential amplifier, which not only has outstanding performance but consumes only 135mW at full bandwidth, addresses this requirement and further demonstrates Analog Devices' pioneering role in developing leading edge processes and linking those with tangible, breakthrough products".

The AD8351 simplifies analogue to digital conversion by allowing the user to adjust the common mode voltage and set the gain from 0 to 26dB (voltage gains from 1 to 20) through a single external resistor.

The AD8351 provides a wide bandwidth (-3dB) of 2.2GHz with a gain of 12dB, low noise spectral density of 2.2nV/rt-Hz, 2nd/3rd order harmonic distortion of -79/-81dBc at 70MHz, slew rate of 11kV/us and exceptional settling/overdrive recovery.

Operation is specified from a single 3 or 5V supply drawing just 27mA quiescent current.

The device will operate over the temperature range from -40 to +85C.

The AD8351 has been fully specified at the common IF frequencies 10, 70, 140 and 240MHz, and is suitable for fully differential signal paths, single-ended-to-differential applications and DC-coupled applications.

The AD8351 is currently sampling and available in a compact 10-pin microSOIC package.

The AD8351 is priced at $3.69 per unit in 1000-piece quantities.

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