LTC5509 UUWUAPPLICATIO S I FOR ATIOOperation The Schottky detector is biased at about 60µA and drives a peak detector capacitor of 28pF. The LTC5509 RF detector integrates several functions to provide RF power detection over frequencies ranging from Modes of Operation 300MHz to 3GHz. These functions include an internally compensated buffer amplifier, an RF Schottky diode peak MODESHDNOPERATION detector and level shift amplifier to convert the RF feedback Shutdown Low Disabled signal to DC and a delay circuit to avoid voltage transients Enable High Power Detect at VOUT when coming out of shutdown. The LTC5509 does not incorporate gain compression. Consequently, it offers Applications a linear transfer relationship between RF input voltage and DC output voltage. The LTC5509 can be used as a self-standing signal strength measuring receiver for a wide range of input signals from Buffer Amplifier –30dBm to 6dBm for frequencies from 300MHz to 3GHz. The buffer amplifier is capable of driving a 2mA load. The The LTC5509 can be used as a demodulator for AM and buffer amplifier typically has an output voltage range of ASK modulated signals with data rates up to 1.5MHz. 0.25V to 3V with VCC = 3.6V. At lower supply voltages the Depending on specific application needs, the RSSI output maximum output swing is reduced. can be split into two branches, providing AC-coupled data (or audio) output and DC-coupled, RSSI output for signal RF Detector strength measurements and AGC. The internal RF Schottky diode peak detector and level The LTC5509 can be used for RF power detection and shift amplifier converts the RF input signal to a low control. Refer to Application Note 91, “Low Cost Coupling frequency signal. The detector demonstrates excellent Methods for RF Power Detectors Replace Directional efficiency and linearity over a wide range of input power. Couplers.” Demo Board Schematic VCC R3 E4 22k SHDN C1 33pF ENABLE 1 RFIN 2 SHDN RF J1 DISABLE 3 LTC5509 R1 68Ω JP1 R2 GND GND (OPT) 68Ω VCC E2 (OPT) E1 VOUT VOUT VCC VCC E3 C5 C2 C3 E5 GND (OPT) 0.1µF 100pF GND 5509 AI01 5509f 6