QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 849 750MA, 1.2MHZ SYNCHRONOUS BOOST CONVERTER LTC3499EDD DESCRIPTION Demonstration circuit 849 is a 750mA, 1.2MHz Syn- circuit also demonstrates the advantages of output chronous Boost Converter with Reverse Battery Pro- disconnect and inrush current limiting. Small circuit size and low component count make the tection featuring the LTC 3499EDD. The demo board LTC3499EDD suitable for use in many space- demonstrates a DC/DC boost converter, with a conscious applications such as Medical Equipment, 750mA switch current limit, providing a 3.3V output Digital Cameras, MP3 Players, and other Portable De- at 250mA from a two cell input voltage, or a 5V out- vices. Other integrated features include peak current put at 170mA from either a two cell or a Li-ion bat- limit, soft-start, antiringing control and thermal shut- tery. The LTC3499EDD offers integrated reverse bat- down. tery protection up to -6V for both the part and the load, drawing typically less than 1uA of current. Design files for this circuit board are available. Call The input voltage of this supply can also be increased the LTC factory. higher than the output, but thermal limitations reduce the output current that can be delivered. See LTC is a trademark of Linear Technology Corporation Vin>Vout Operation section on the datasheet. The Table 1. Performance Summary (T = 25C) 3.3V Output A PARAMETERS CONDITION VALUE Minimum Input Voltage 1.8V Maximum Input Voltage 3V Output Voltage V V = 1.8V, I =0mA to 250mA 3.3V 3% OUT IN OUT Output Voltage V V = 3.0V, I =0mA to 500mA 3.3V 3% OUT IN OUT Typical Output Ripple V V = 1.8V, I = 250mA 20mV OUT IN OUT PP Typical efficiency V =2.4V , I = 160mA 90% IN OUT Table 2. Performance Summary (T = 25C) 5V Output A PARAMETERS CONDITION VALUE Minimum Input Voltage 1.8V Maximum Input Voltage 4.2V Output Voltage V V = 1.8V, I =0mA to 170mA 5V 3% OUT IN OUT Output Voltage V V = 2.7V, I =0mA to 270mA 5V 3% OUT IN OUT Output Voltage V V = 4.2V, I =0mA to 480mA 5V 3% OUT IN OUT Typical Output Ripple V V = 2.7V, I = 270mA 22mV OUT IN OUT PP Typical efficiency V =2.7V , I = 160mA 88% IN OUT 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 849 750MA, 1.2MHZ SYNCHRONOUS BOOST CONVERTER QUICK START PROCEDURE Demonstration circuit 849 is easy to set up to evalu- 2. With power off, connect the input power supply to ate the performance of the LTC3499EDD. Refer to VIN and GND. Figure 1 for proper measurement equipment setup 3. Turn on the power at the input. and follow the procedure below: 4. Check for the proper output voltages. NOTE: When measuring the input or output voltage NOTE: If there is no output, temporarily disconnect ripple, care must be taken to avoid a long ground lead the load to make sure that the load is not set too on the oscilloscope probe. Measure the input or out- high. put voltage ripple by touching the probe tip directly across the VIN or VOUT and GND terminals. See NOTE: Once the proper output voltages are estab- Figure 2 for proper scope probe technique. lished, adjust the loads within the operating range and observe the output voltage regulation, ripple 1. Place jumpers in the following positions: voltage, efficiency and other parameters. JP1 Run. JP2 3.3V or 5V (depending on output desired) Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2