ADI AD8337-EVALZ-INV

The AD8337 is a low noise, single-ended, linear-in-dB, general-purpose, variable gain amplifier (VGA) usable at frequencies from dc to 100 MHz; the −3 dB bandwidth is 280 MHz. Excellent bandwidth uniformity across the entire gain range and low output referred noise make the AD8337 ideal for gain trim applications and for driving high speed analog-to-digital converters (ADCs). Excellent dc characteristics combined with high speed make the AD8337 particularly suited for industrial ultrasound, PET scanners, and video applications. Dual-supply operation enables gain control of negative going pulses, such as those generated by photodiodes or photomultiplier tubes. The AD8337 uses an exclusive X-AMP architecture with 24 dB gain range scaled to 19.7 dB/V, referenced to VCOM. The AD8337 preamplifier is configured in a current feedback architecture optimized for gains of 6 dB to 24 dB. The AD8337 is characterized by a noninverting preamplifier gain of 2× using a pair of 100 Ω resistors. The attenuator has a range of 24 dB, and the output amplifier has a fixed gain of 8× (18.06 dB). The lowest nominal gain range is 0 dB to 24 dB and can be shifted up or down by adjusting the preamplifier gain. Series connected AD8337 devices provide larger gain ranges, interstage filtering to suppress noise and distortion, and nulling of offset voltages.

• Low noise Voltage noise δ = 2.2 nV/√Hz Current noise = 4.8 pA/√Hz (positive input)
• Wide bandwidth (-3 dB) = 280 MHz
• Nominal gain range: 0 dB to 24 dB (preamp gain = 6 dB)
• Gain scaling: 19.7 dB/V
• DC-coupled
• Single-ended input and output
• High speed uncommitted op amp input
• Supplies: +5 V, ±2.5 V, or ±V
• Low power: 78 mW with ±2.5 V supplies

• Gain trim
• PET scanners
• High performance AGC systems
• I/Q signal processing
• Video
• Industrial and medical ultrasound
• Radar receivers