QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 748A 50MHZ TO 3GHZ RF POWER DETECTOR WITH 60dB DYNAMIC RANGE LT5534 DESCRIPTION Demonstration circuit 748A is a wide range RF power detector featuring the LT®5534. The LT5534 is a 50MHz to 3GHz monolithic RF power detector capable of measuring RF signals over a 60dB dynamic range. The RF signal in a decibel scale is precisely converted into DC voltage on a linear scale. The 60dB input dynamic range is achieved using cascaded RF detectors and RF limiters. Their outputs are summed to generate an accurate log-linear DC voltage proportional to the input RF signal in dB. The output is buffered with a low output impedance driver. The LT5534 features superior temperature stability and fast transient response (typical full-scale setting time is 38ns). Design files for this circuit board are available. Call the LTC factory. Table 1. Typical Performance Summary (VCC = 3V, EN = 3V, TA = 25°C, source impedance = 50Ω Ω, unless otherwise noted. Test circuit shown in Figure 1.) PARAMETER CONDITION VALUE Supply Voltage 2.7V to 5.25V Supply Current 7mA Input Impedance 2kΩ Output Impedance 32Ω Output DC voltage No RF Input Signal 142mV fRF = 50MHz RF Input Power Range Dynamic Range -58dBm to +2dBm ±3dB Linearity Error, TA = -40°C to 85°C Output Slope Output Variation vs. Temperature 60dB 44mV/dB Pin = -48dBm to -14dBm, TA = -40°C to 85°C 0.007dB/°C fRF = 900MHz RF Input Power Range Dynamic Range -60dBm to 0dBm ±3dB Linearity Error, TA = -40°C to 85°C Output Slope Output Variation vs. Temperature 60dB 41mV/dB Pin = -48dBm to -14dBm, TA = -40°C to 85°C 0.008dB/°C fRF = 1900MHz RF Input Power Range Dynamic Range -63dBm to -2dBm ±3dB Linearity Error, TA = -40°C to 85°C Output Slope 61dB 36.6mV/dB Output Variation vs. Temperature Pin = -48dBm to -14dBm, TA = -40°C to 85°C 0.012dB/°C Output intercept 50Ω External Termination, TA = -40°C to 85°C -64dBm fRF = 2500MHz RF Input Power Range Dynamic Range -63dBm to -3dBm ±3dB Linearity Error, TA = -40°C to 85°C Output Slope Output Variation vs. Temperature 60dB 35mV/dB Pin = -48dBm to -14dBm, TA = -40°C to 85°C 0.025dB/°C 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 748A 50MHZ TO 3GHZ RF POWER DETECTOR WITH 60dB DYNAMIC RANGE QUICK START PROCEDURE Demonstration circuit 748A is easy to set up to evaluate the performance of the LT5534. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: 5. Connect RF signal generator output to demo board RF in port (SMA connector J1) via coaxial cable. 6. Using a jumper cable, connect demo board Vcc pin (E1) to EN pin (E4). Now the detector is enabled (on) and is ready for measurement. NOTE: Demonstration circuit 748A is optimized for evaluations over the frequency range from 50MHz to 2.5GHz. Its RF input port is well matched with better than 10dB return loss up to 2.5GHz. At higher frequencies, return loss can be improved with proper matching. 1. Connect DC power supply negative (-) output to demo board Gnd pin (E3 or E5). 2. Connect DC power supply positive (+) output (2.7V to 5.25V) to demo board Vcc pin (E1). NOTE: Do not exceed 5.5V, the absolute maximum supply voltage. 3. Connect voltmeter negative (-) lead to demo board Gnd pin (E3 or E5). 4. Connect voltmeter positive (+) lead to the demo board Vout pin (E2). NOTE: Make sure that the power is not applied to the EN pin before it is applied to the Vcc pin. The voltage on the EN pin must never exceed the voltage on the Vcc pin. 7. Apply an RF input signal and measure Vout DC voltage. NOTE: Do not exceed +10dBm, the absolute maximum RF input power. 8. The dynamic range is defined as the range over which the linearity error is within ±3dB. The linearity error is calculated by the difference between the incremental slope of the output and the average output slope from -48dBm to -14dBm. Figure 1. Proper Measurement Equipment Setup 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 748A 50MHZ TO 3GHZ RF POWER DETECTOR WITH 60dB DYNAMIC RANGE 3