Features and Benefits
- 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
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.
The signal inputs are single-ended, allowing them to be matched and connected directly to a directional coupler. Their input impedance is nominally 3 kΩ at low frequencies.
The AD8302 includes a phase detector of the multiplier type, but with precise phase balance driven by the fully limited signals appearing at the outputs of the two logarithmic amplifiers. Thus, the phase accuracy measurement is independent of signal level over a wide range.
The phase and gain output voltages are simultaneously available at loadable ground referenced outputs over the standard output range of 0 V to 1.8 V. The output drivers can source or sink up to 8 mA. A loadable, stable reference voltage of 1.8 V is available for precise repositioning of the output range by the user.
In controller applications, the connection between the gain output pin VMAG and the setpoint control pin MSET is broken. The desired setpoint is presented to MSET and the VMAG control signal drives an appropriate external variable gain device. Likewise, the feedback path between the phase output pin VPHS and its setpoint control pin PSET may be broken to allow operation as a phase controller.
The AD8302 is fabricated on Analog Devices’ proprietary, high performance 25 GHz SOI complementary bipolar IC process. It is available in a 14-lead TSSOP package and operates over a –40°C to +85°C temperature range. An evaluation board is available.
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
AD8302-EVALZ is a 4-layer, FR4-based printed circuit board. For normal operation, it requires a 5V/50 mA power supply. The 5V power supply should be connected to the vector pins leads labeled VP and GND. The two RF input signals are applied to two edge-mounted SMA type RF connectors (INPA and INPB). The gain and phase output signals are accessible via edge-mounted SMA connectors.
The EVAL-AD8302-ARDZ shield illustrates the functionality of the AD8302, a gain and phase detector which operates from low frequency up to 2.7 GHz. The voltage outputs of the AD8302 are routed to the ANALOG IN connector of the Arduino base board. This allows the RF power detector’s output voltage to be easily digitized and processed by the Arduino base board’s integrated six-channel ADC.
Tools & Simulations
ADIsimPLL enables the rapid and reliable evaluation of new high performance PLL products from ADI. It is the most comprehensive PLL Synthesizer design and simulation tool available today. Simulations performed include all key non-linear effects that are significant in affecting PLL performance. ADIsimPLL removes at least one iteration from the design process, thereby speeding the design- to-market.
ADIsimRF is an easy-to-use RF signal chain calculator. Cascaded gain, noise, distortion and power consumption can be calculated, plotted and exported for signal chains with up to 50 stages. ADIsimRF also includes an extensive data base of device models for ADI’s RF and mixed signal components.
Product Selection Guide (1)
Technical Articles (7)
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.