QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1078 MEAN-S Q U AR ED R F P O W ER D ET EC T O R LT5570 DESCRIPTION Demonstration circuit 1078 (DC1078A) is a MeanSquared RF Power detector featuring the LT5570. The LT5570 is a wide dynamic range RF detector, operational from 40MHz to 2700MHz. The input dynamic range at 2140MHz with ±1dB nonlinearity is 51dB (from –38dBm to +13dBm. The detector output voltage slope is normally 37mV/dB, and the typical output variation over temperature is ±0.3dB at 2140MHz. NOTE: DC1078A demo circuit is optimized for input frequency of 2140MHz +/- 150MHz. Refer to page 3 for modifications for 2700MHz and 880MHz. Design files for this circuit 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 Supply Voltage 4.75V to 5.25V Supply Current Shutdown Current VALUE 26.5mA 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 0.5µs Fall Time 1.6V to 0.2V, 90% to 10%, C1 = 22nF, FRF = 2140 MHz 8µs ENBL Voltage ENBL Input Current Input Frequency Range 2140MHz to 2700MHz f = 2140MHz Linear Dynamic Range ±1 dB linearity error 51 dB Slope 36.5mV/dB Logarithmic Intercept -42.4dBm Output Variation vs Temperature PIN = -50 to +13dBm ±0.3 dB Deviation from CW Response 12 dB peak-to-average ratio (4 carrier WCDMA) 0.2 dB ±1 dB linearity error 48 dB f = 2700MHz Linear Dynamic Range Slope 36.4mV/dB Logarithmic Intercept -38.5dBm Output Variation vs Temperature PIN = -50 to +13dBm ±0.2 dB Deviation from CW Response 12 dB peak-to-average ratio (4 carrier WCDMA) 0.5 dB 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1078 MEAN-S Q U AR ED R F P O W ER D ET EC T O R QUICK START PROCEDURE Demonstration circuit 1078 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: 5. 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. 1. Connect voltmeter’s negative (-) lead to demo board GND test point (TP2). 6. 2. Connect voltmeter’s positive (+) lead to the demo board OUTPUT test point (TP4). 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. 3. Connect DC power supply’s negative (-) output to demo board GND test point (TP2). 4. Connect DC power supply’s positive (+) output (4.75V to 5.25V) to demo board VCC test point (TP1). NOTE: Do not exceed 5.5V, the absolute maximum supply voltage. 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. 7. Apply RF input signal and measure OUTPUT DC voltages. NOTE: Do not exceed +15dBm, the absolute maximum RF input power. Figure 1. Proper Measurement Equipment Setup 2 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1078 MEAN-S Q U AR ED R F P O W ER D ET EC T O R DEMO BOARD MODIFICATIONS: Demo board modifications for RF input frequency of 2700MHz Part Notes Value Manufacturer Part Number L1 Remove L1 inductor. 1.2pF Murata, GRM1555C1H1R2CZ01 2.2nH TOKO, LL1005-FHL2N2S Place 1.2pF capacitor instead of inductor L1. C7 Remove capacitor C7. Place 2.2nH inductor instead of capacitor C7. T1 Remove T1 balun (LDB212G1020C-001). Murata, LDB212G4020C-001 Place LDB212G4020C-001 Murata balun instead. NOTE: Refer to demo board schematic on Page 4 Demo board modifications for RF input frequency of 880MHz Part Notes Value Manufacturer Part Number L1 Remove L1 inductor. 1.8nH TOKO, LL1005-FHL1N8S No placement n/a Place 1.8nH inductor instead. C7 Remove capacitor C7. T1 Remove T1 balun (LDB212G1020C-001). Murata, LDB21869M20C-001 Place LDB21869M20C-001Murata balun instead. NOTE: Refer to demo board schematic on Page 4 Note: Consult factory for demo board modifications for other frequencies. 3 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1078 MEAN-S Q U AR ED R F P O W ER D ET EC T O R 4