Datasheet AD8302 (Analog Devices)

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LF–2.7 GHz RF/IF Gain and Phase Detector AD8302 FEATURES FUNCTIONAL BLOCK DIAGRAM Measures Gain/Loss and Phase up to 2.7 GHz Dual Demodulating Log Amps and Phase Detector AD8302 MFLT Input Range –60 dBm to 0 dBm in a 50
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System VIDEO OUTPUT – A + + Accurate Gain Measurement Scaling (30 mV/dB) VMAG – – INPA Typical Nonlinearity < 0.5 dB 60dB LOG AMPS OFSA (7 DETECTORS) Accurate Phase Measurement Scaling (10 mV/Degree) Typical Nonlinearity < 1 Degree MSET Measurement/Controller/Level Comparator Modes Operates from Supply Voltages of 2.7 V–5.5 V COMM PHASE DETECTOR Stable 1.8 V Reference Voltage Output PSET Small Signal Envelope Bandwidth from DC to 30 MHz APPLICATIONS OFSB 60dB LOG AMPS – (7 DETECTORS) VPHS INPB RF/IF PA Linearization + Precise RF Power Control VIDEO OUTPUT – B PFLT Remote System Monitoring and Diagnostics 1.8V Return Loss/VSWR Measurements VPOS BIAS x3 VREF Log Ratio Function for AC Signals PRODUCT DESCRIPTION
The signal inputs are single-ended, allowing them to be matched The AD8302 is a fully integrated system for measuring gain/loss and connected directly to a directional coupler. Their input and phase in numerous receive, transmit, and instrumentation impedance is nominally 3 kΩ at low frequencies. applications. It requires few external components and a single The AD8302 includes a phase detector of the multiplier type, supply of 2.7 V–5.5 V. The ac-coupled input signals can range but with precise phase balance driven by the fully limited signals from –60 dBm to 0 dBm in a 50 Ω system, from low frequencies appearing at the outputs of the two logarithmic amplifiers. up to 2.7 GHz. The outputs provide an accurate measurement Thus, the phase accuracy measurement is independent of signal of either gain or loss over a ± 30 dB range scaled to 30 mV/dB, level over a wide range. and of phase over a 0°–180° range scaled to 10 mV/degree. Both subsystems have an output bandwidth of 30 MHz, which The phase and gain output voltages are simultaneously available may optionally be reduced by the addition of external filter at loadable ground referenced outputs over the standard output capacitors. The AD8302 can be used in controller mode to range of 0 V to 1.8 V. The output drivers can source or sink up force the gain and phase of a signal chain toward predetermined to 8 mA. A loadable, stable reference voltage of 1.8 V is avail- setpoints. able for precise repositioning of the output range by the user. The AD8302 comprises a closely matched pair of demodulating In controller applications, the connection between the gain logarithmic amplifiers, each having a 60 dB measurement range. output pin VMAG and the setpoint control pin MSET is broken. By taking the difference of their outputs, a measurement of The desired setpoint is presented to MSET and the VMAG the magnitude ratio or gain between the two input signals is control signal drives an appropriate external variable gain device. available. These signals may even be at different frequencies, Likewise, the feedback path between the phase output pin VPHS allowing the measurement of conversion gain or loss. The AD8302 and its setpoint control pin PSET may be broken to allow may be used to determine absolute signal level by applying the operation as a phase controller. unknown signal to one input and a calibrated ac reference signal The AD8302 is fabricated on Analog Devices’ proprietary, high to the other. With the output stage feedback connection dis- performance 25 GHz SOI complementary bipolar IC process. It is abled, a comparator may be realized, using the setpoint pins available in a 14-lead TSSOP package and operates over a –40°C MSET and PSET to program the thresholds. to +85°C temperature range. An evaluation board is available. REV. B
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Document Outline FEATURES PRODUCT DESCRIPTION FUNCTIONAL BLOCK DIAGRAM AD8302-SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION PIN FUNCTION DESCRIPTIONS CAUTION Equivalent Circuits Typical Performance Characteristics GENERAL DESCRIPTION AND THEORY Basic Theory Structure BASIC CONNECTIONS Measurement Mode Interfacing to the Input Channels Dynamic Range Cross Modulation of Magnitude and Phase Modifying the Slope and Center Point Comparator and Controller Modes APPLICATIONS Measuring Amplifier Gain and Compression Reflectometer CHARACTERIZATION SETUPS AND METHODS Gain Phase OUTLINE DIMENSIONS Ordering Guide Revision History