GENERAL DESCRIPTION

The AD8335 is a quad variable gain amplifier (VGA) with low noise preamplifier intended for cost and power sensitive applications. Each channel features a gain range 48 dB, fully differential signal paths, active input preamplifier matching, and user-selectable maximum gains of 46 dB and 38 dB. Individual gain controls are provided for each channel.

FEATURES

   Low noise preamplifier (PrA)

   Voltage noise = 1.3 nV/√Hz typical

   Current noise = 2.4 pA/√Hz typical

   NF = 7 dB (RS = RIN = 50 Ω)

   Single-ended input; VIN max = 625 mV p-p

   Active input match

  Input SNR (noise bandwidth = 20 MHz) = 92 dB

VGA

   Differential output

   VOUT max = 5 V p-p, RL = 500 Ω differential

   Gain range (8 dB output gain step)

   −10 dB to +38 dB—LO gain mode

   −2 dB to +46 dB—HI gain mode

   Accurate linear-in-dB gain control

PrA + VGA performance

   −3 dB bandwidth of 70 MHz

   Excellent overload performance

Supply: 5 V

Power consumption

   95 mW/channel (380 mW total)

   65 mW/channel (PrA off; 260 mW total)

Power-down

APPLICATIONS

Medical imaging (ultrasound, gamma cameras)

Sonar

Test and measurement

Precise, stable wideband gain control