QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 747 LOG-LINEAR RF/IF DETECTOR LT5537 DESCRIPTION Demonstration circuit 747 is a log-linear RF/IF detector ended 50W input). The detector output voltage slope is normally 20mV/dB, and the typical temperature featuring the LT 5537. coefficient is 0.01dB/C at 200MHz. The LT5537 is a wide dynamic range RF/IF log detec- tor, operational from below 10MHz to 1000MHz. The lower limit of the operating frequency range can be Design files for this circuit board are available. Call extended to near DC by the use of an external capaci- the LTC factory. tor. The input dynamic range at 200MHz with 3dB LTC is a trademark of Linear Technology Corporation nonlinearity is 90dB (from 76dBm to 14dBm, single- Table 1. Typical Performance Summary (V = 3V, ENBL = 3V, T = 25C, unless otherwise noted. Test circuit shown in Figure 1.) CC A PARAMETER CONDITION VALUE Supply Voltage 2.7V to 5.25V Supply Current 13.5mA Shutdown Current ENBL = Low 500A Low, Chip Disabled 0.3V max ENBL Voltage High, Chip Enabled 1.0V min V = 0V 0A ENBL ENBL Input Current V = 3V 100A ENBL RF/IF Input DC Common Mode Voltage (V 0.4) V CC Small-Signal Impedance Measured at 200MHz 1.73kW // 1.45pF Output Start Voltage No Input Signal Present 0.4V Response Time Input from 30dBm to 0dBm, C = 2.5pF 110ns LOAD Baseband Modulation Bandwidth Output Load Capacitance = 2.5pF 6MHz Input Frequency Range Operation at lower frequency is possible. See LT5537 datasheet. 10MHz to 1GHz 50W Termination 200MHz 14.0dBm Maximum Input Power for Monotonic Output 600MHz 11.6dBm 1GHz 9.4dBm f = 10MHz 3dB Error 88.8dB Linear Dynamic Range 1dB Error 72.5dB Slope R1 = 33k (The output slope is adjustable using R1.) 19.6mV/dB Intercept V = 0V, extrapolated -97dBm OUT Sensitivity can be improved by as much as 10dB by using a narrow- Sensitivity -76.7dBm band input matching network. See LT5537 datasheet. Temperature Coefficient P = -20dBm -0.007dB/C IN 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 747 LOG-LINEAR RF/IF DETECTOR f = 100MHz 3dB Error 90.5dB Linear Dynamic Range 1dB Error 82.8dB Slope R1 = 33k (The output slope is adjustable using R1.) 20.3mV/dB Intercept V = 0V, extrapolated -95dBm OUT Sensitivity can be improved by as much as 10dB by using a narrow- Sensitivity -77dBm band input matching network. See LT5537 datasheet. Temperature Coefficient P = -20dBm -0.004dB/C IN f = 200MHz 3dB Error 90.3dB Linear Dynamic Range 1dB Error 83.5dB Slope R1 = 33k (The output slope is adjustable using R1.) 21.2mV/dB Intercept V = 0V, extrapolated -94dBm OUT Sensitivity can be improved by as much as 10dB by using a narrow- Sensitivity -76.4dBm band input matching network. See LT5537 datasheet. Temperature Coefficient P = -20dBm 0.010dB/C IN f = 400MHz 3dB Error 88.2dB Linear Dynamic Range 1dB Error 70.8dB Slope R1 = 33k (The output slope is adjustable using R1.) 23.1mV/dB Intercept V = 0V, extrapolated -91dBm OUT Sensitivity can be improved by as much as 10dB by using a narrow- Sensitivity -75.3dBm band input matching network. See LT5537 datasheet. Temperature Coefficient P = -20dBm 0.019dB/C IN f = 600MHz 3dB Error 85.8dB Linear Dynamic Range 1dB Error 72.5dB Slope R1 = 33k (The output slope is adjustable using R1.) 25.2mV/dB Intercept V = 0V, extrapolated -89dBm OUT Sensitivity can be improved by as much as 10dB by using a narrow- Sensitivity -74.1dBm band input matching network. See LT5537 datasheet. Temperature Coefficient P = -20dBm 0.026dB/C IN f = 1GHz 3dB Error 63.5dB Linear Dynamic Range 1dB Error 51.7dB Slope R1 = 33k (The output slope is adjustable using R1.) 31.4mV/dB Intercept V = 0V, extrapolated -80dBm OUT Sensitivity can be improved by as much as 10dB by using a narrow- Sensitivity -69.2dBm band input matching network. See LT5537 datasheet. Temperature Coefficient P = -20dBm 0.031dB/C IN 2