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 ±5 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