GENERAL DESCRIPTION
The AD8318 is a demodulating logarithmic amplifier, capable of accurately converting an RF input signal to a corresponding decibel-scaled output voltage. It employs the progressive compression technique over a cascaded amplifier chain, each stage of which is equipped with a detector cell. The device is used in measurement or controller mode. The AD8318 maintains accurate log conformance for signals of 1 MHz to 6 GHz and provides useful operation to 8 GHz. The input range is typically 60 dB (referenced to 50 Ω) with error less than ±1 dB. The AD8318 has a 10 ns response time that enables RF burst detection to beyond 45 MHz. The device provides unprecedented logarithmic intercept stability vs. ambient temperature conditions. A 2 mV/°C slope temperature sensor output is also provided for additional system monitoring. A single supply of 5 V is required. Current consumption is typically 68 mA. Power consumption decreases to <1.5 mW when the device is disabled.

FEATURES
   Wide bandwidth: 1 MHz to 8 GHz
   High accuracy: ±1.0 dB over 55 dB range (f < 5.8 GHz)
   Stability over temperature: ±0.5 dB
   Low noise measurement/controller output (VOUT)
   Pulse response time: 10 ns/12 ns (fall/rise)
   Integrated temperature sensor
   Small footprint LFCSP
   Power-down feature: <1.5 mW at 5 V
   Single-supply operation: 5 V at 68 mA
   Fabricated using high speed SiGe process

APPLICATIONS
   RF transmitter PA setpoint control and level monitoring
   RSSI measurement in base stations, WLAN, WiMAX, and
      radars