●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.
●### Features and Benefits
● Complete Multistage Log-Limiting IF Amplifier
● 100 dB Dynamic Range:
●–78 dBm to +22 dBm (Re 50 O)
● Programmable Limiter Gain and Output Current
●Differential Outputs to 10 mA,
●2.4 V p-p
●Overall Gain 100 dB, Bandwidth 500 MHz
●Constant Phase (Typical 680 ps Delay Skew)
● 500 ns Power-Up Time, <1 mA Sleep Current
● Stable RSSI Scaling Over Temperature and Supplies:
●20 mV/dB Slope, –95 dBm Intercept
●±0.4 dB RSSI Linearity up to 200 MHz
● Single Supply of +2.7 V to +6.5 V at
●16 mA Typical
● Fully Differential Inputs,
●RIN = 1kΩ, CIN = 2.5 pF
