NORWOOD, Mass., 7 Feb. 2008. Analog Devices Inc. in Norwood, Mass., is introducing a digitally programmable variable gain amplifier (VGA) with transmit driver that moves signals over power lines, cables, and other applications with low impedance.
The AD8260 operates on a 3.3-volt power supply and has a transmit driver that produces +/-200 milliamps output up to 100 kHz, and greater than +/-100 milliamps above that frequency.
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 ideal for converting D-A converter differential output signals to a voltage that can directly drive very low impedances. The AD8260 can drive a 10 (OMEGA) load with 2 Vpp at 10 MHz. In addition, the chip dissipates just 93 milliwatts of power, which is less than half that of competing devices.
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-by-5-millimeter chip-scale package.
The receiver section consists of a single-ended input preamplifier and linear-in-dB, differential-output VGA. The differential output facilitates the interface to modern low-voltage, high-speed A-D converters.
Versatile single- and dual-supply operation allow gain control of negative-going pulses, such as generated by photodiodes or photo-multiplier tubes, and allows for the processing of band-pass signals on a single supply. The AD8260 preamplifier is user-configurable with external resistors for gains greater than 6 dB.
For more information contact Analog Devices online at www.analog.com.