QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1314A RF POWER DETECTOR LT5581 DESCRIPTION Demonstration Circuit 1314A is a Mean-Squared Power Detector featuring the LT®5581 IC. The LT5581 is a wide dynamic range Mean Squared RF Power Detector, operational from 10MHz to 6GHz. The input dynamic range at 6GHz, with ±1dB nonlinearity, is 40dB (from –34dBm to +6dBm, single-ended 50Ω input). The detector output voltage slope is normally 31mV/dB, and the typical output variation over temperature is ±0.5dB at 880MHz. The 1314A Demo Circuit is optimized for wide frequency range of 10MHz to 2.2GHz. However, input match can be optimized up to 6GHz with simple external matching. Design files for this demo board are available. Call the LTC factory. LTC is a trademark of Linear Technology Corporation Typical Performance Summary (VCC = 3.3V, ENBL = 3.3V, TA = 25°C, unless otherwise noted. Test circuit shown in Figure 1.) PARAMETER CONDITION VALUE Supply Voltage 2.7V to 5.25V Supply Current 1.4mA Shutdown Current ENBL Voltage ENBL Input Current ENBL = Low 0.2µA Low, Chip Disabled 0.3V max HIGH, Chip Enabled 2V min VENBL = 0V 0µA VENBL = 5V 20µA Output Start Voltage No Input Signal Present 0.2V Rise Time 0.2V to 1.6V, 10% to 90%, C1 = 22nF, FRF = 2140 MHz 1µs Fall Time 1.6V to 0.2V, 90% to 10%, C1 = 22nF, FRF = 2140 MHz 8µs Input Frequency Range Optimized for DC1314A demo board 10MHz to 6GHz ±1 dB linearity error 40 dB f = 450MHz Linear Dynamic Range Slope 31mV/dB Logarithmic Intercept -42dBm Output Variation vs Temperature PIN = -34 to +6dBm ±1 dB Deviation from CW Response 12 dB peak-to-average ratio (4 carrier WCDMA) ±0.5 dB ±1 dB linearity error 31dB f = 5800MHz Linear Dynamic Range Slope 31mV/dB Logarithmic Intercept -33dBm Output Variation vs Temperature PIN = -25 to +6dBm ±1 dB Deviation from CW Response WiMAX OFDM Burst; PIN = -25 to +6dBm ±0.2dB 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1314A RF POWER DETECTOR QUICK START PROCEDURE Demonstration Circuit 1314A is easy to set up to evaluate the performance of the LT5581. Refer to Figure 1 for measurement equipment setup and follow the procedure below: Connect voltmeter’s negative (-) lead to demo board GND test point (E4). Connect voltmeter’s positive (+) lead to the demo board OUTPUT test point (J2). Connect DC power supply’s negative (-) output to demo board GND test point (E3 and E4). Connect DC power supply’s positive (+) output (2.7V to 5.25V) to demo board VCC test point (E1 and E2). Do not exceed 5.5V, the absolute maximum supply voltage. Connect signal generator’s output to demo board INPUT port (SMA connector J1) via coaxial cable. A 3dB attenuator may be inserted to improve input match. Using a jumper cable, connect demo board VCC test point (E1) to ENBL test point (E2). Now the detector is enabled (on) and is ready for measurement. NOTES: 1. The voltage on the EN test point must never exceed VCC + 0.3V. 2. For digitally modulated signals, an oscilloscope can be used to observe the AC components of the output. 3. Pins 4, 5 and 6 are internally connected to ground. In the customer designs, the users have the choice to leave them as no connect as in the demo board, or connect them to ground. Pin 8, CSQ is the Optional Low Frequency Range Extension Capacitor. Use this pin for frequencies below 250MHz. Connect 0.01uF from Pin 8 to ground for 10MHz operation. Apply RF input signal and measure OUTPUT DC voltages. Do not exceed +15dBm, the absolute maximum RF input power. 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1314A RF POWER DETECTOR DEMO BOARD MODIFICATIONS: Modifications at RF input port for other frequency ranges: Figure 1. Proper Measurement Equipment Setup 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1314A RF POWER DETECTOR 4