PRODUCT DESCRIPTION

The AD8302 is a fully integrated system for measuring gain/loss and phase in numerous receive, transmit, and instrumentation applications. It requires few external components and a single supply of 2.7 V–5.5 V. The ac-coupled input signals can range from –60 dBm to 0 dBm in a 50 Ω system, from low frequencies up to 2.7 GHz. The outputs provide an accurate measurement of either gain or loss over a ±30 dB range scaled to 30 mV/dB, and of phase over a 0°–180° range scaled to 10 mV/degree. Both subsystems have an output bandwidth of 30 MHz, which may optionally be reduced by the addition of external filter capacitors. The AD8302 can be used in controller mode to force the gain and phase of a signal chain toward predetermined setpoints.

The AD8302 comprises a closely matched pair of demodulating logarithmic amplifiers, each having a 60 dB measurement range. By taking the difference of their outputs, a measurement of the magnitude ratio or gain between the two input signals is available. These signals may even be at different frequencies, allowing the measurement of conversion gain or loss. The AD8302 may be used to determine absolute signal level by applying the unknown signal to one input and a calibrated ac reference signal to the other. With the output stage feedback connection disabled, a comparator may be realized, using the setpoint pins MSET and PSET to program the thresholds.

FEATURES

Measures Gain/Loss and Phase up to 2.7 GHz

Dual Demodulating Log Amps and Phase Detector

Input Range –60 dBm to 0 dBm in a 50 Ω System

Accurate Gain Measurement Scaling (30 mV/dB)

Typical Nonlinearity < 0.5 dB

Accurate Phase Measurement Scaling (10 mV/Degree)

Typical Nonlinearity < 1 Degree

Measurement/Controller/Level Comparator Modes

Operates from Supply Voltages of 2.7 V–5.5 V

Stable 1.8 V Reference Voltage Output

Small Signal Envelope Bandwidth from DC to 30 MHz

APPLICATIONS

RF/IF PA Linearization

Precise RF Power Control

Remote System Monitoring and Diagnostics

Return Loss/VSWR Measurements

Log Ratio Function for AC Signals