LTC5564 APPLICATIONS INFORMATION Operation typical VOUTADJ voltage for the desired VOUT DC output The LTC5564 is a fast RF detector with a high speed offset in each gain setting. amplifier and comparator. This product integrates these RF Detector functions to provide RF detection over frequencies ranging from 600MHz to 15GHz. These functions include an RF The internal temperature compensated Schottky diode Schottky peak detector, internally compensated operational peak detector converts the RF input signal to a low amplifier, and a comparator as shown in Figure 1. The frequency signal. The detector demonstrates excellent LTC5564 has selectable amplifier gains, amplifier output efficiency and linearity over a wide range of input power offset adjustment and comparator latch enable capabilities. levels. The Schottky diode is nominally biased at 180µA and drives a parallel reservoir capacitor-resistor network Amplifier of 8pF and 1.2k. The high speed amplifier offers four gain settings and Comparator is capable of driving a 1.7mA load with an output swing range of approximately 295mV to VCC – 1.6V. See Table 1 The high speed comparator compares the external refer- for gain setting operation. ence voltage on the VREF pin to the internal signal voltage V The V P from the peak detector and produces the output logic OUTADJ pin provides output DC offset adjustment signal V to satisfy various interface requirements. Setting V COMP . VP is the internal comparator positive input OUT as shown in Figure 1. to 500mV also provides the maximum demodulation bandwidth in each gain mode. See Electrical and Typical LEN provides latch enable/disable functionality as shown Performance Characteristics curve. See Table 1 for the in Figure 2. Table 1. Gain Mode and Typical VOUTADJ OperationPING1G0GAIN MODEDESCRIPTIONREQUIRED VOUTADJ FOR A GIVEN DC OUTPUT OFFSET GND GND GAIN1 Minimum Gain Setting (VOUT/RFIN ≈ 1.5dB) VOUTADJ = 0.95 • VOUT – 0.174 GND VCCA GAIN2 VOUT/RFIN Increased 6dB VOUTADJ = (VOUT – 0.07)/2.10 VCCA GND GAIN4 VOUT/RFIN Increased 12dB VOUTADJ = (VOUT + 0.05)/3.16 VCCA VCCA GAIN8 VOUT/RFIN Increased 18dB VOUTADJ = (VOUT + 0.25)/5.26 Note: Valid range for VOUT ≈ 0.195V ≤ VOUT ≤ VCC – 1.6 LEN VREF VP VCOMP 5564 F02 VOUT VOUT VOUT TRANSPARENT LATCHED TRANSPARENT Figure 2. LTC5564 Comparator Latch Enable Function 5564fc 10 For more information www.linear.com/LTC5564 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Simplified Block Diagram Applications Information Revision History Typical Application Related Parts