Features and Benefits
- Matched VGAs and programmable filters
- Maximum gain: 53 dB
- Continuous gain control range: 60 dB
- Filter bypass mode I/Q bandwidth
- ±1 dB gain flatness: >1250 MHz
- 4-pole Butterworth filter I/Q bandwidth: 36 MHz to 720 MHz RMS detector
- IMD3: <−55 dBc for 1.5 V p-p composite output
- HD2, HD3: <−55 dBc for 1.5 V p-p output
- Noise figure: 10.5 dB at maximum gain
- NF < 11 dB over 12 dB of VGA2 gain backoff
- 100 Ω differential input, low impedance output
- Optional dc output offset correction
- SPI-programmable filter corners
- Single 3.3 V supply operation with power-down feature
The ADRF6520 is a matched pair of fully differential low noise and low distortion programmable filters and variable gain amplifiers (VGAs). Each channel is capable of rejecting large, out of band interferers while reliably boosting the wanted signal, thus reducing the bandwidth and resolution requirements on the analog-to-digital converters (ADCs). The excellent matching between channels and their high spurious-free dynamic range over all gain and bandwidth settings make the ADRF6520 ideal for quadrature-based (IQ) communication systems with dense constellations, multiple carriers, and nearby interferers. The filter corners, enable, and dc offset correction loop enable are all programmable via a serial peripheral interface (SPI).
The first VGA that precedes the filters offers 30 dB of continuous gain control with a maximum gain of 18 dB and sets a differential input impedance of 100 Ω. The filters provide a four-pole Butterworth response with −1 dB corner frequencies: 36 MHz, 72 MHz, 144 MHz, 288 MHz, 432 MHz, 576 MHz, and 720 MHz. For operation beyond 720 MHz, the filter can be disabled and completely bypassed, thereby extending the −1 dB bandwidth up to 1.25 GHz. A wideband rms detector is available to monitor the signal at the filter inputs. A fixed gain amplifier of 6 dB immediately follows the filter. The postfilter VGA provides 30 dB of continuous gain control with a maximum gain of 12 dB. The output buffers offer an additional 18 dB of gain and provide a differential output impedance of 20 Ω. The output buffers are capable of driving 1.5 V p-p into 100 Ω loads at better than 55 dBc nominal for the third-order intermodulation distortion (IMD3). Independent, built in, dc offset correction loops for each channel can be disabled via the SPI if fully dc-coupled operation is desired. The high-pass corner frequency is determined by external capacitors on the CHP1 and CHP2 pins and the postfilter VGA gain.
The ADRF6520 operates from a 3.15 V to 3.45 V supply and consumes a maximum supply current of 425 mA. When fully disabled, it consumes ≤10 mA. The ADRF6520 is fabricated in an advanced silicon-germanium BiCMOS process and is available in a 32-lead, exposed pad LFCSP. Performance is specified over the −40°C to +85°C temperature range.
- Point-to-point and point-to-multipoint radios
- Baseband IQ receivers
- Diversity receivers
- ADC drivers
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
This user guide describes the ADRF6520-EVALZ evaluation board kit for the ADRF6520 dual-channel, programmable, low-pass filters and variable gain amplifiers (VGAs) and how to configure the evaluation board to evaluate the ADRF6520 in a single-ended or differential configuration.
The ADRF6520 features a filter bypass mode that extends the bandwidth greater than 1 GHz. The ADRF6520-EVALZ evaluation board allows the user to test all the functions and features offered by the ADRF6520 including low-pass filtering, analog gain control, and the on-chip rms detectors. Signal path traces are matched and are intuitively laid out on the left and right side of the evaluation board, providing easy interfacing with other evaluation boards.
The ADRF6520-EVALZ uses an SDP-S controller board to program its signal peripheral interface (SPI) port using the ADRF6520 Evaluation Software.
A full description and complete specifications for the ADRF6520 are provided in the ADRF6520 data sheet and should be consulted in conjunction with this user guide when using the evaluation board.
Tools & Simulations
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.
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.