AD8309ARU

Overview

The AD8309ARU is a complete IF limiting amplifier and demodulating logarithmic amplifier designed for frequencies from 5 MHz to 500 MHz. It provides a Received Signal Strength Indication (RSSI) output with a dynamic range of 100 dB, spanning from -78 dBm to +22 dBm into a 50 Ω load. The device features a stable transfer slope of 20 mV/dB and an intercept of -95 dBm. It includes a programmable limiter output stage offering 100 dB total gain and differential outputs capable of driving up to 10 mA. Powered by a single supply between 2.7 V and 6.5 V at a typical quiescent current of 16 mA, it operates within the industrial temperature range of -40 °C to +85 °C.

Feature Summary

• Provides accurate RSSI measurement over a 100 dB dynamic range with high linearity in the central portion of the scale.
• Integrates a fully differential input stage with moderately high impedance suitable for direct coupling or matching networks.
• Delivers a hard-limited square-wave output useful for recovering frequency and phase modulation data.
• Features a CMOS-compatible control interface allowing rapid power-up and low standby current consumption.

Applications

• Receivers for frequency and phase modulation
• Very wide range IF and RF power measurement
• Receiver signal strength indication (RSSI)
• Low cost radar and sonar signal processing
• Instrumentation including network and spectrum analyzers

Procurement Notes

Verify the specific package suffix RU corresponds to the 16-lead TSSOP housing required for your PCB layout. Confirm that the operating environment remains within the specified -40 °C to +85 °C industrial temperature range. Ensure the supply voltage does not exceed the absolute maximum rating of 7.5 V to prevent permanent damage. Check for ESD sensitivity requirements during handling and assembly processes.

Selection Notes

Select this component when a combined log-amplifier and limiter function is needed for IF or RF signals up to 500 MHz. It is suitable for applications requiring precise signal strength monitoring alongside demodulation capabilities. Consider the input impedance characteristics and potential need for external matching networks if interfacing with 50 Ω sources directly. Evaluate the power consumption against system thermal constraints given the single-supply operation.

Part Context

The AD8309 belongs to Analog Devices' family of demodulating logarithmic amplifiers. It utilizes an advanced complementary bipolar process with silicon-on-insulator isolation techniques. This technology enables high gain-bandwidth products necessary for accurate small-signal detection at radio frequencies while maintaining stability across varying temperatures and supply voltages.

Replacement Considerations

Public confirmed substitute part numbers: AD8309ARU-REEL, AD8309ARU-REEL7.