PRODUCT DESCRIPTION
The AD640 is a complete monolithic logarithmic amplifier. A single AD640 provides up to 50 dB of dynamic range for frequencies from dc to 120 MHz. Two AD640s in cascade can provide up to 95 dB of dynamic range at reduced bandwidth. The AD640 uses a successive detection scheme to provide an output current proportional to the logarithm of the input voltage. It is laser calibrated to close tolerances and maintains high accuracy over the full military temperature range using supply voltages from ±4.5 V to ±7.5 V.

FEATURES
  Complete, Fully Calibrated Monolithic System
  Five Stages, Each Having 10 dB Gain, 350 MHz BW
  Direct Coupled Fully Differential Signal Path
  Logarithmic Slope, Intercept and AC Response are Stable Over Full Military Temperature Range
  Dual Polarity Current Outputs Scaled 1 mA/Decade
  Voltage Slope Options (1 V/Decade, 100 mV/dB, etc.)
  Low Power Operation (Typically 220 mW at 65 V)
  Low Cost Plastic Packages Also Available

APPLICATIONS
  Radar, Sonar, Ultrasonic and Audio Systems
  Precision Instrumentation from DC to 120 MHz
  Power Measurement with Absolute Calibration
  Wide Range High Accuracy Signal Compression
  Alternative to Discrete and Hybrid IF Strips
  Replaces Several Discrete Log Amp ICs