DEMO CIRCUIT 1530A QUICK START GUIDE LTC3829EUHF HIGH EFFICIENCY, 3-PHASE, SINGLE OUTPUT, SYNCHRONOUS BUCK CONVERTER DESCRIPTION Demonstration circuit 1530A is a high efficiency, 3phase, synchronous buck converter with 7V to 14V input range. It can supply 60A maximum load current at 1.5V output. The demo board uses the LTC®3829EUHF controller. The LTC3829 is a feature-rich single-output 3-phase synchronous buck controller with on-chip drivers, remote output voltage sensing, inductor DCR temperature compensation, phase shedding, nonlinear control and adaptive voltage positioning (AVP). It is suitable for input from 4.5V to 38V and output up to 5V. The LTC3856 can provide high efficiency, high power density and versatile power solutions for telecom and datacom systems, industrial and medical instruments, DC power distribution systems and computer systems. The controller is available in 38-pin 5mm × 7mm QFN and 38-pin TSSOP packages. Table 1. The RUN pin (JP1) provides enable feature. To shut down the converter, one simple way is to force the RUN pin below 1.2V (JP1: OFF). Use JP4 jumper to select burst mode, stage shedding mode or forced continuous mode operation. The nonlinear control function is set by JP11. Switching frequency is preset at about 400KHz, and it can be easily modified from 250KHz to 770KHz. On-board dynamic circuit is also available for transient test. Design files for this circuit board are available. Call the LTC factory. Performance Summary (TA = 25°C) PARAMETER CONDITION Input Voltage Range VALUE 7V to 14V Output Voltage, VOUT VIN = 7-14V, IOUT = 0A to 60A 1.5V ±2% Maximum Output Current, IOUT VIN = 7-14V, VOUT = 1.5V 60A Typical Efficiency VIN = 12V, VOUT = 1.5V, IOUT = 60A 86.4% Typical Switching Frequency 400kHz 1 LTC3829EUHF QUICK START PROCEDURE Demonstration circuit 1530A is easy to set up to evaluate the performance of the LTC3829EUHF. Refer to Figure 1 for the proper measurement equipment setup and follow the procedure below: 1. With power off, connect the input power supply to Vin (7V-14V) and GND (input return). 2. Connect the 1.5V output load between Vout and GND (Initial load: no load). 3. Connect the DVMs to the input and outputs. 4. Turn on the input power supply and check for the proper output voltages. Vout should be 1.5V+/-2%. 5. Once the proper output voltages are established, adjust the loads within the operating range and observe the output voltage regulation, ripple voltage and other parameters. Note: When measuring the output or input voltage ripple, do not use the long ground lead on the oscilloscope probe. See Figure 2 for the proper scope probe technique. Short, stiff leads need to be soldered to the (+) and (-) terminals of an output capacitor. The probe’s ground ring needs to touch the (-) lead and the probe tip needs to touch the (+) lead. 2 LTC3829EUHF Figure 1. Proper Measurement Equipment Setup + COUT VOUT - GND Figure 2. Measuring Output Voltage Ripple 3 LTC3829EUHF Figure 3. Efficiency vs load current 4 LTC3829EUHF 5 LTC3829EUHF 6