QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 878 1MHZ SYNCHRONOUS STEP-UP DC/DC CONVERTER LTC3458LEDE DESCRIPTION Demonstration circuit 878 is a 1MHZ Synchronous converters, USB VBUS Power and OLED displays. Step-Up DC/DC Converter featuring the Other integrated features include externally pro- grammable burst mode threshold, peak current limit, LTC 3458LEDE. The demo board demonstrates a soft-start, antiringing control and thermal shutdown. DC/DC boost converter, with a 1.7A switch, providing 5V at 300mA to 900mA depending on input voltage. Design files for this circuit board are available. Call The circuit demonstrates the advantages of output the LTC factory. disconnect and inrush current limiting. Small circuit size and low component count make the LTC3458L , LTC and LT are registered trademarks of Linear Technology Corporation. suitable for use in many space-conscious applica- tions such as handheld instruments, point-of-load Table 1. Performance Summary (T = 25C) A PARAMETERS CONDITION VALUE Minimum Input Voltage 2.0V Maximum Input Voltage 5V Output Voltage V V = 2V, I =300mA 5V 3% OUT IN OUT Output Voltage V V = 2.7V, I =450mA 5V 3% OUT IN OUT Output Voltage V V = 3.3V, I =650mA 5V 3% OUT IN OUT Output Voltage V V = 4.2V, I =900mA 5V 3% OUT IN OUT Typical Output Ripple V V = 3.3V, I = 650mA 30mV OUT IN OUT PP Typical efficiency V =4.2V , I = 900mA 86% IN OUT C9 used only when operating supply with long inductive input leads. QUICK START PROCEDURE Demonstration circuit 878 is easy to set up to evalu- 1. Place jumpers in the following positions: ate the performance of the LTC3458LEDE. Refer to JP1 Run, JP2 Auto on. Figure 1 for proper measurement equipment setup 2. With power off, connect the input power supply to and follow the procedure below: Vin and GND. NOTE: When measuring the input or output voltage 3. Turn on the power at the input. ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or out- NOTE: Make sure that the input voltage does not ex- put voltage ripple by touching the probe tip directly ceed 6V. across the Vin or Vout and GND terminals. See 4. Check for the proper output voltages. Figure 2 for proper scope probe technique. 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 878 1MHZ SYNCHRONOUS STEP-UP DC/DC CONVERTER NOTE: If there is no output, temporarily disconnect and observe the output voltage regulation, ripple the load to make sure that the load is not set too voltage, efficiency and other parameters. high. NOTE: Once the proper output voltages are estab- lished, adjust the loads within the operating range Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2