QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC667 4A MONOLITHIC SYNCHRONOUS STEP-DOWN REGULATOR WITH TRACKING LTC3416 DESCRIPTION Demonstration circuit 667 is a high efficiency, high rent power switches in the LTC3416. The LTC3416 frequency buck converter, incorporating the LTC3416 also incorporates OPTI-LOOP compensation, so that monolithic synchronous regulator. DC667 operates in the DC667 can be optimized to provide fast transient forced continuous operation and provides tracking of response over a wide range of line and load condi- another power supply rail. It operates from an input tions. All these features make the DC667 perfectly voltage range of 2.25V to 5.5V and provides a regu- suited for battery powered, hand-held applications. lated output voltage from 0.8V to 5V. DC667 can de- Design files for this circuit board are available. Call liver high power up to 4A of output current - in a the LTC factory. relatively small circuit, thanks to 67mohm high cur- QUICK START PROCEDURE Demonstration circuit DC667 is easy to set up to NOTE: Make sure that the input voltage VIN does not evaluate the performance of the LTC3416EFE. Refer exceed 5.5V. to Figure 1 for proper measurement equipment setup 6. Check for the output voltages VOUT = 2.5V and follow the procedure below: If there is no output, temporarily disconnect the NOTE: When measuring the input or output voltage load to make sure that the load is not set too high. ripple, care must be taken to avoid a long ground lead 7. Once the proper output voltages are established, on the oscilloscope probe. Measure the input or out- adjust the loads within 4A range and observe the put voltage ripple by touching the probe tip directly output voltage regulation, ripple voltage, efficiency across the VIN or VOUT and GND terminals. See Fig- and other parameters. ure 2 for proper scope probe technique. 8. To test tracking functions, place JP2 to ON posi- 1. Place jumper JP1 in the ON position. tion, and connect TRACK terminal to 1.25V Voltage 2. Connect Jumper JP4 for 2.5V Output Voltage. supply (through a voltage divider, the voltage on Leave JP3, JP5 and JP6 unconnected. Track pin of the IC is about 550mV), the output 3. With power off, connect the input power supply voltage will be regulated at 1.75V. VIN to VIN and GND. 9. Connect TRACK terminal to GND, the VOUT should 4. Connect TRACK terminal to VIN (JP2 to Off posi- be less than 200mV in normal operation. tion), tracking function is disabled. 10. To test 1.8V output voltage, connect JP3 and leave 5. Apply input power at the VIN slowly, by increasing JP4, JP5 and JP6 unconnected. Repeat the proce- VIN from 0V to 5.5V. dure 3 to 7. Follow the similar procedure for other output voltage tests. 1GND VIN QUICK START GUIDE FOR DEMONSTRATION CIRCUIT DC667 4A MONOLITHIC SYNCHRONOUS STEP-DOWN REGULATOR WITH TRACKING Figure 1. Proper Measurement Equipment Setup Figure 2. Scope Probe Placement for Measuring Input or Output Ripple 2