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Variable gain amplifier drives low impedances from one power supply

Norwood, Mass.—Analog Devices Inc. (ADI) has introduced a
digitally programmable VGA (variable gain amplifier) with transmit
driver for driving signals over power lines, cables, and other applications with low impedance.

The AD8260 operates on a single 3.3-V power supply and has a transmit
driver that produces ±200-mA output up to 100 kHz, and greater than ±100-mA above that frequency. According to ADI, competing products using a discrete VGA, output driver and pre-amp consume 90 percent more board space, and require multiple power supplies.

The AD8260 VGA operates at -3dB bandwidth of 200-MHz and includes
a 30-dB gain range digitally adjustable in 3-dB gain steps providing the headroom needed for losses introduced in various cabling systems.

The VGA features 2.4nV/rtHz input voltage noise and driver with a
built-in gain of 1.5, which is suitable for converting D/A converter differential output signals to a voltage that can directly drive very low impedances. The AD8260 can fully drive a 10 Ω load with 2 Vpp at 10MHz. In addition, the chip dissipates just 93 mW of power, which is less than half that of competing devices, ADI said.

The AD8260 includes a high-current driver, usable as a transmitter, and a low-noise digitally programmable VGA, which is useable as a receiver, combined in a 5 mm x 5 mm chip-scale package.

Pricing: $3.79 in 1,000-unit quantities.
Availability: Sampling now, with full volume production scheduled for March 2008.

Datasheet: Click here.

Analog Devices, www.analog.com

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