DEMO CIRCUIT 1280 LT3471EDD QUICK START GUIDE LT3471EDD Dual 1.3A, 1.2MHz Boost/Inverter in 3mmx3mm DFN DESCRIPTION Demonstration circuit 1280A is a dual output con- Both outputs on this demo board can be modified verter featuring the LT3471EDD in Boost and In- for higher voltages. These circuits are intended for verter configurations. Both converters are powered space-conscious applications such as digital cam- from the same 4.5V to 10V input source. The eras, cellular phones, palmtop computers PC Boost converter puts out 12V at 300mA and the cards, miniature disk drives, xDSL power supplies, Inverter -12V at 200mA. The demo circuit dem- flash memory products, local 5V or 12V supplies onstrates small size and low component count. and LCD displays. The LT3471 operates with inputs as high as 16V but in this demo board the input is limited by the magnitude of the Boost output. In a Boost con- Design files for this circuit board are available. verter the input needs to be less than the output. Call the LTC factory. The DC1280A is designed so that the Inverting L, LTC, LTM, LT, Burst Mode, OPTI-LOOP, Over-The-Top and PolyPhase are registered trademarks of Linear Technology Corporation. Adaptive Power, C-Load, converter can easily be configured as a Boost. In- DirectSense, Easy Drive, FilterCAD, Hot Swap, LinearView, Module, Micropower SwitcherCAD, Multimode Dimming, No Latency , No Latency Delta-Sigma, No structions are included in the schematic. R , Operational Filter, PanelProtect, PowerPath, PowerSOT, SmartStart, SENSE Both circuits are designed to demonstrate the soft SoftSpan, Stage Shedding, SwitcherCAD, ThinSOT, UltraFast and VLDO are trademarks of Linear Technology Corporation. Other product names may be trade- start feature, advantages of the 1.2MHz switching marks of the companies that manufacture the products. frequency and the internal 42V/1.3A switches. PERFORMANCE SUMMARY FOR BOOST CONVERTER Specifications are at TA = 25C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Supply Range 4.5 10 V IN V Output Voltage Range V = 4.5V, I = 300mA 11.64 12 12.36 V OUT IN LOAD V = 4.5V, I = 300mA 40 mV RIPPLE IN LOAD V = 4.5V, I = 300mA 84 % EFFICIENCY IN LOAD PERFORMANCE SUMMARY FOR INVERTING REGULATOR Specifications are at TA = 25C SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Supply Range 4.5 12 V IN V Output Voltage Range V = 4.5V, I = 200mA -11.64 -12 -12.36 V OUT IN LOAD V = 4.5V, I = 200mA 10 mV RIPPLE IN LOAD V = 4.5V, I = 200mA 74 % EFFICIENCY IN LOAD QUICK START PROCEDURE Demonstration circuit 1280 is easy to set up to fer to Figure 1 for proper measurement equipment evaluate the performance of the LT3471EDD. Re- setup and follow the procedure below: 1 LT3471EDD NOTE. When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope 4. Check for the proper output voltages. probe. Measure the input or output voltage ripple by touching the probe tip directly across the Vin or Vout and GND terminals. See NOTE. If there is no output, temporarily disconnect the load to Figure 2 for proper scope probe technique. make sure that the load is not set too high. 1. Place jumpers in the following positions: 5. Once the proper output voltages are estab- lished, adjust the loads within the operating JP1 ON range and observe the output voltage regula- JP2 ON tion, ripple voltages, efficiency and other pa- rameters. 2. With power off, connect the input power supply (4.5V to 10V) to Vin and GND. 3. Turn on the power at the input. Figure 1. Proper Measurement Equipment Setup for DC1280A 2