DEMO MANUAL DC2105A LTC3630AEMSE/LTC3630EMSE High Efficiency High Voltage 500mA Synchronous Step-Down Converter Description Demonstration circuit 2105A is a 500mA output DC/DC ripple and reducing component size. A terminal (FBO) power supply. There are two versions: DC2105A-A is a is available to allow multiple boards to be paralleled for board featuring LTC 3630A, with 4V to 76V input range increasing output current. DC2105A-B is a board featuring LTC3630, with 4V to 65V Output voltage between 800mV and V can be pro- IN input range. The LTC3630A/LTC3630 operates in a high grammed using optional resistors, although higher voltage efficiency Burst Mode operation and includes internal output capacitors will be required. high and low side switches. The board provides jumper The LTC3630A/LTC3630 data sheet gives a complete de- selected output voltages of 1.8V, 3.3V, 5V and an option scription of the operation and application information. for additional voltages. LTC3630A/LTC3630 has internal The data sheet must be read in conjunction with this soft-start and a provision for increasing soft-start time. demo manual. Included on the board is an ON/OFF jumper that can also Design files for this circuit board are available at be configured as a precision undervoltage lockout. Ad- DEMO MANUAL DC2105A Quick s p D This DC2105A can be evaluated using the setup shown 5. Once the proper output voltages are established, adjust in Figure 1. the load and input voltage within the operating range and observe the output voltage regulation, ripple volt- 1. Connect the DVMs to the input and output. Select 5V age and other parameters. setting using jumper JP1 (lower position) and JP2 (upper position), select ON position for JP3. NOTES: 2. With input power supply set for 0V, connect the sup- 1. IMPORTANT: 60V or higher voltage can result in an ply to V and GND terminals using short (less than electric shock if care is not taken. Also, hot plugging IN 10 inches) leads, preferably twisted leads. Connect a the circuit to a power supply that has more than 40V suitable load to V and GND terminals. present at its output can produce a high voltage tran- OUT sient exceeding the absolute maximum input voltage 3. Slowly increase the input power supply to 10V. Observe which can damage the LTC3630A/LTC3630. output voltage and verify that it meets the specifications in the Performance Summary. Measure output voltage 2. When measuring the input or output voltage ripple, with and without the load. care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the input or output voltage 4. Move jumpers JP1 and JP2 to the other two fixed volt- ripple by touching the probe tip directly across the V IN age settings and verify that each output voltage meets or V and GND terminals. See Figure 3 for proper OUT the values as shown in the Performance Summary. scope probe technique. NOTE: A 10F, 100V electrolytic capacitor is necessary when evaluating circuit with input voltages greater than 40V, using long input wires and hot plugging circuit into a powered input supply. See Figure 2. Figure 1. Proper Measurement Equipment Setup dc2105af 2 ure roce tart