LF2.7 GHz a 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 System VIDEO OUTPUT A + + Accurate Gain Measurement Scaling (30 mV/dB) VMAG INPA Typical Nonlinearity < 0.5 dB 60dB LOG AMPS (7 DETECTORS) OFSA Accurate Phase Measurement Scaling (10 mV/Degree) Typical Nonlinearity < 1 Degree MSET Measurement/Controller/Level Comparator Modes PHASE Operates from Supply Voltages of 2.7 V5.5 V COMM DETECTOR Stable 1.8 V Reference Voltage Output PSET Small Signal Envelope Bandwidth from DC to 30 MHz APPLICATIONS OFSB 60dB LOG AMPS VPHS (7 DETECTORS) 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 k 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 V5.5 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 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 0180 range scaled to 10 mV/degree. The phase and gain output voltages are simultaneously available Both subsystems have an output bandwidth of 30 MHz, which at loadable ground referenced outputs over the standard output may optionally be reduced by the addition of external filter range of 0 V to 1.8 V. The output drivers can source or sink up capacitors. The AD8302 can be used in controller mode to to 8 mA. A loadable, stable reference voltage of 1.8 V is avail- force the gain and phase of a signal chain toward predetermined able for precise repositioning of the output range by the user. setpoints. In controller applications, the connection between the gain The AD8302 comprises a closely matched pair of demodulating output pin VMAG and the setpoint control pin MSET is broken. logarithmic amplifiers, each having a 60 dB measurement range. The desired setpoint is presented to MSET and the VMAG By taking the difference of their outputs, a measurement of control signal drives an appropriate external variable gain device. the magnitude ratio or gain between the two input signals is Likewise, the feedback path between the phase output pin VPHS available. These signals may even be at different frequencies, and its setpoint control pin PSET may be broken to allow allowing the measurement of conversion gain or loss. The AD8302 operation as a phase controller. may be used to determine absolute signal level by applying the 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 40C MSET and PSET to program the thresholds. to +85C temperature range. An evaluation board is available. REV. B Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. use, nor for any infringements of patents or other rights of third parties that Tel: 781.329.4700 201 8 Analog Devices, Inc. All rights reserved. may result from its use. No license is granted by implication or otherwise www.analog.com Technical Support under any patent or patent rights of Analog Devices.(T = 25 C, V = 5 V, VMAG shorted to MSET, VPHS shorted to PSET, 52.3 shunt AD8302SPECIFICATIONS A S resistors connected to INPA and INPB, for Phase measurement P = P , unless otherwise noted.) INPA INPB Parameter Conditions Min Typ Max Unit OVERALL FUNCTION Input Frequency Range >0 2700 MHz Gain Measurement Range P at INPA, P at INPB = 30 dBm 30 dB IN IN Phase Measurement Range at INPA > at INPB 90 Degree IN IN Reference Voltage Output Pin VREF, 40C T +85C 1.72 1.8 1.88 V A INPUT INTERFACE Pins INPA and INPB Input Simplified Equivalent Circuit To AC Ground, f 500 MHz 3 2k pF Input Voltage Range AC-Coupled (0 dBV = 1 V rms) 73 13 dBV re: 50 60 0 dBm Center of Input Dynamic Range 43 dBV 30 dBm MAGNITUDE OUTPUT Pin VMAG Output Voltage Minimum 20 Log (V /V ) = 30 dB 30 mV INPA INPB Output Voltage Maximum 20 Log (V /V ) = +30 dB 1.8 V INPA INPB Center Point of Output (MCP) V = V 900 mV INPA INPB Output Current Source/Sink 8 mA Small Signal Envelope Bandwidth Pin MFLT Open 30 MHz Slew Rate 40 dB Change, Load 20 pF 10 k 25 V/ s Response Time Rise Time Any 20 dB Change, 10%90% 50 ns Fall Time Any 20 dB Change, 90%10% 60 ns Settling Time Full-Scale 60 dB Change, to 1% Settling 300 ns PHASE OUTPUT Pin VPHS Output Voltage Minimum Phase Difference 180 Degrees 30 mV Output Voltage Maximum Phase Difference 0 Degrees 1.8 V Phase Center Point When = 90 900 mV INPA INPB Output Current Drive Source/Sink 8 mA Slew Rate 25 V/ s Small Signal Envelope Bandwidth 30 MHz Response Time Any 15 Degree Change, 10%90% 40 ns 120 Degree Change C = 1 pF, to 1% Settling 500 ns FILT 100 MHz MAGNITUDE OUTPUT Dynamic Range 1 dB Linearity P = 30 dBm (V = 43 dBV) 58 dB REF REF 0.5 dB Linearity P = 30 dBm (V = 43 dBV) 55 dB REF REF 0.2 dB Linearity P = 30 dBm (V = 43 dBV) 42 dB REF REF Slope From Linear Regression 29 mV/dB Deviation vs. Temperature Deviation from Output at 25C 40C T +85C, P = P = 30 dBm 0.25 dB A INPA INPB Deviation from Best Fit Curve at 25C 40C T +85C, P = 25 dB, P = 30 dBm 0.25 dB A INPA INPB Gain Measurement Balance P = P = 5 dBm to 50 dBm 0.2 dB INPA INPB PHASE OUTPUT Dynamic Range Less than 1 Degree Deviation from Best Fit Line 145 Degree Less than 10% Deviation in Instantaneous Slope 143 Degree Slope (Absolute Value) From Linear Regression about 90 or +90 10 mV/Degree Deviation vs. Temperature Deviation from Output at 25C 40C T +85C, Delta Phase = 90 Degrees 0.7 Degree A Deviation from Best Fit Curve at 25C 40C T +85C, Delta Phase = 30 Degrees 0.7 Degree A REV. 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