QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 728 1MHZ SYNCHRONOUS STEP-UP DC/DC CONVERTER LTC3458EDE DESCRIPTION Demonstration circuit 728 is a 1MHz Synchronous Step- displays. Other integrated features include externally programmable burst mode threshold, peak current limit, Up DC/DC Converter featuring the LTC 3458EDE. The soft-start, anti-ringing control and thermal shutdown. demo circuit demonstrates a DC/DC boost converter, NOTE: If supply is going to be used in Fixed Frequency with a 1.5A switch, providing 7V at 200mA to 800mA Mode, use a 50K Ohm resistor to tie the Burst pin to the depending on input voltage. The circuit demonstrates output voltage. the advantages of output disconnect and inrush current limiting. Small circuit size and low component count Design files for this circuit board are available. Call make the LTC3458 suitable for use in many space- the LTC factory. conscious applications such as handheld instruments, point-of-load converters, USB VBUS Power and OLED LTC is a registered trademark of Linear Technology Corporation Table 1. Performance Summary (T = 25C) A PARAMETERS CONDITION VALUE Minimum Input Voltage 2.0V Maximum Input Voltage 6V Output Voltage V V = 2V, I =200mA 7V 3% OUT IN OUT Output Voltage V V = 2.7V, I =300mA 7V 3% OUT IN OUT Output Voltage V V = 3.3V, I =400mA 7V 3% OUT IN OUT Output Voltage V V = 4.2V, I =550mA 7V 3% OUT IN OUT Output Voltage V V = 5V, I =700mA 7V 3% OUT IN OUT Output Voltage V V = 6V, I =800mA 7V 3% OUT IN OUT Typical Output Ripple V V = 3.3V, I = 400mA 20mV OUT IN OUT PP Typical efficiency V =4.2V , I = 300mA 87.5% IN OUT C9 used only when operating supply with long inductive input leads. QUICK START PROCEDURE Demonstration circuit 728 is easy to set up to evaluate voltage ripple by touching the probe tip directly across the performance of the LTC3458EDE. Refer to Figure 1 the Vin or Vout and GND terminals. See Figure 2 for for proper measurement equipment setup and follow the proper scope probe technique. procedure below: 1. Place jumpers in the following positions: NOTE: When measuring the input or output voltage rip- JP1 On, JP2 Auto On. ple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 728 1MHZ SYNCHRONOUS STEP-UP DC/DC CONVERTER 2. With power off, connect the input power supply to Vin NOTE: If there is no output, temporarily disconnect the and GND. load to make sure that the load is not set too high. 3. Turn on the power at the input. NOTE: Once the proper output voltages are established, adjust the loads within the operating range and observe NOTE: Make sure that the input voltage does not ex- the output voltage regulation, ripple voltage, efficiency ceed 6V. and other parameters. 4. Check for the proper output voltages. Figure 1. Proper Measurement Equipment Setup Figure 2. Measuring Input or Output Ripple 2