5 MHz TO 500 MHz, 100 dB Demodulating Logarithmic Amplifier with Limiter Output

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Product Details

The AD8309 is a 500 MHz detecting logarithmic amplifier, based on the successive detection technique. This "log amp" is useful for received signal strength indication (RSSI) and phase detection in cellular base stations, radar and other radio transceiver applications.

It provides a dynamic range of 100 dB with an accuracy of ±0.4 dB over the central 80 dB and operates up to 500 MHz. The logarithmic output is proportional to the logarithm of the input signal, providing a 0.4 V to 2.5 V DC signal over the 100 dB input range. A limiter output is also provided which amplifies the input signal by 100 dB, providing a stable limited output with a maximum of ±100 ps phase skew. This limiter output is useful for demodulating FSK and PSK modulated signals.

The AD8309 operates from a single 2.7 V to 5.5 V dc power supply, drawing 20 mA typical. It is supplied in a 16 pin plastic TSSOP package.

An evaluation board is available for this product and may be ordered using the following product number: AD8309-EVAL. Schematic and layout for this evaluation board is contained in the product datasheet.

Product Lifecycle

icon-recommended 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


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EVAL-AD8309 Circuit Diagram

Product Details

AD8309-EVALZ is a full featured, 4-layer, FR4-based evaluation board designed to allow easy evaluation of all features of the AD8309. RF input, limiter output and VLOG output SMA connections with single ended setups are featured. There is an option of full differential signaling on the RF input and limiter output at card edge if the user desires. Access to the +5V/16 mA supply is achieved with clip leads to the Vs and COM testpoints; it has a range from +2.7 to +6.5V.

Tools & Simulations

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Design Tools

Reference Materials

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Design Resources

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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.

AD8309 Material Declaration
PCN-PDN Information Quality And Reliability Symbols and Footprints


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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.

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Evaluation Boards Pricing displayed is based on 1-piece.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.