AD8318 Datasheet | Analog Devices

FEATURES - Wide bandwidth: 1 MHz to 8 GHz - High accuracy: ±1.0 d B over 55 d B range (f < 5.8 GHz) - Stability over temperature: ±0.5 d B - 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 m W at 5 V - Single-supply operation: 5 V at 68 m A - Fabricated using high speed Si Ge process APPLICATIONS - RF transmitter PA setpoint control and level monitoring - RSSI measurement in base stations, WLAN, Wi MAX, and radars 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 pression 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 d B (referenced to 50 Ω) with error less than ±1 d B. 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 m V/°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 m A. Power consumption decreases to <1.5 m W when the device is disabled. The AD8318 can be configured to provide a control voltage to a VGA, such as a power amplifier or a measurement output, from Pin VOUT. Because the output can be used for controller applications, wideband noise is minimal. In this mode, the setpoint control voltage is applied to VSET. The feedback loop through an RF amplifier is closed via VOUT, the output of which regulates the amplifier output to a magnitude corresponding to VSET. The AD8318 provides 0 V to 4.9 V...