AD8264ACPZ-R7

The AD8264 is a quad, linear-in-dB, general-purpose, variable gain amplifier (VGA) with a preamplifier (preamp), and a flexible differential output buffer. DC coupling, combined with wide bandwidth, makes this amplifier a very good pulse processor. Each channel includes a single-ended input preamp/VGA section to preserve the wide bandwidth and fast slew rate for low distortion pulse applications. A 6 dB differential output buffer with common-mode and offset adjustments enable direct coupling to most modern high speed analog-to-digital converters (ADCs), using the converter reference output for perfect dc matching levels. The −3 dB bandwidth of the preamp/VGA is dc to 235 MHz, and the bandwidth of the differential driver is 80 MHz. The floating gain control interface provides a precise linear-in-dB scale of 20 dB/V and is easy to interface to a variety of external circuits. The gain of each channel is adjusted independently, and all channels are referenced to a single pin, GNLO. Combined with a multioutput, digital-to-analog converter (DAC), each section of the AD8264 can be used for active calibration or as a trim amplifier. Operation from a bipolar power supply enables amplification of negative voltage pulses generated by current-sinking pulses into a grounded load, such as is typical of photodiodes or photomultiplier tubes (PMT). Delay-free processing of wideband video signals is also possible.

Applications

• Multichannel data acquisition
• Positron emission tomography
• Gain trim
• Industrial and medical ultrasound
• Radar receivers

Key features

• Low noise Voltage noise: 2.3 nV/√Hz Current noise: 2 pA/√Hz
• Wide bandwidth Small signal: 235 MHz (VGAx); 80 MHz (output amplifier) Large signal: 80 MHz (1 V p-p)
• Gain range 0 to 24 dB (input to VGA output) 6 to 30 dB (input to differential output)
• Gain scaling: 20 dB/V
• DC-coupled
• Single-ended input and differential output
• Supplies: ±2.5 V to ±5 V
• Low power: 140 mW per channel at ±3.3 V