QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A MEAN-SQUARED RF/IF DETECTOR LT5570 DESCRIPTION Demonstration circuit 1077A is a Mean-Squared RF/IF detector featuring the LT®5570 IC. The LT5570 is a wide dynamic range Mean Squared RF Power detector, operational from 40MHz to 2700MHz. The input dynamic range at 880MHz, with ±1dB nonlinearity, is 61dB (from –48dBm to +13dBm, single-ended 50Ω input). The detector output voltage slope is normally 37mV/dB, and the typical output variation over temperature is ±0.4dB at 880MHz. The 1077A Demo Board is optimized for wide frequency range of 40MHz to 880MHz. Design files for this demo board are available. Call the LTC factory. LTC is a trademark of Linear Technology Corporation Table 1. Typical Performance Summary (VCC = 5V, ENBL = 5V, TA = 25°C, unless otherwise noted. Test circuit shown in Figure 2.) PARAMETER CONDITION VALUE Supply Voltage 4.75V to 5.25V Supply Current 26.5mA Shutdown Current ENBL = Low 0.1µA Low, Chip Disabled 1V max HIGH, Chip Enabled 2V min VENBL = 0V 0µA VENBL = 5V 68µA Output Start Voltage No Input Signal Present 0.1V 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 DC1077A demo board 40MHz to 880MHz ±1 dB linearity error 62 dB ENBL Voltage ENBL Input Current f = 500MHz Linear Dynamic Range Slope 36.9mV/dB Logarithmic Intercept -54.8dBm Output Variation vs Temperature PIN = -50 to +13dBm ±0.5 dB Deviation from CW Response 12 dB peak-to-average ratio (4 carrier WCDMA) 0.3 dB ±1 dB linearity error 62 dB f = 880MHz Linear Dynamic Range Slope 36.9mV/dB Logarithmic Intercept -54.8dBm Output Variation vs Temperature PIN = -50 to +13dBm ±0.5 dB Deviation from CW Response 12 dB peak-to-average ratio (4 carrier WCDMA) 0.2 dB 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A MEAN-SQUARED RF/IF DETECTOR QUICK START PROCEDURE Demonstration circuit 1077A is easy to set up to evaluate the performance of the LT5570. Refer to Figure 1 for proper measurement equipment setup and follow the procedure below: 1. Connect voltmeter’s negative (-) lead to demo board GND test point (TP2). 2. Connect voltmeter’s positive (+) lead to the demo board OUTPUT test point (TP4). 3. Connect DC power supply’s negative (-) output to demo board GND test point (TP2). 4. 6. Connect signal generator’s output to demo board INPUT port (SMA connector J1) via coaxial cable. Using a jumper cable, connect demo board VCC test point (E3) to ENBL test point (TP3). Now the detector is enabled (on) and is ready for measurement. Make sure that the power is not applied to ENBL before it is applied to VCC. The voltages on the ENBL test point must never exceed VCC + 0.2V. NOTE: Make sure that the power is not applied to Enable (EN) test point before it is applied to VCC. The voltage on the EN test point must never exceed VCC + 0.2V. Connect DC power supply’s positive (+) output (4.75V to 5.25V) to demo board VCC test point (TP1). Do not exceed 5.5V, the absolute maximum supply voltage. 5. A 3dB attenuator may be inserted to improve input match. 7. Apply RF input signal and measure OUTPUT DC voltages. Do not exceed +15dBm, the absolute maximum RF input power. Figure 1. Proper Measurement Equipment Setup 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A MEAN-SQUARED RF/IF DETECTOR 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1077A MEAN-SQUARED RF/IF DETECTOR DEMO BOARD MODIFICATIONS: Modifications for Single-Ended RF Input configuration without RF Input Transformer: Part Value T2 C8 3.3pF Manufacturer Part Number Notes MA-COM, MABAES0061 Remove T2 transformer AVX, 0402YA330KAT Remove capacitor C8 Place 150 ohm resistor (0402 body size) instead C10 1nF 0805 size capacitor from any supplier Place 1nF capacitor between pins 5 & 1 of T2 transformer (refer to tr-r pin-out on schematic) R2 0-ohm 0-ohm resistor (or copper jumper) Place 0-ohm resistor between pins 2 & 3 of T2 transformer (refer to tr-r pin-out on schematic) NOTE: Refer to the demo board schematic below DC1077A Demo Board Schematic with modifications for Single-Ended RF Input without RF Input Transformer 4