DC1780A-B

DEMO MANUAL DC1780A-B LTM4620EV: High Efficiency, PolyPhase 75A Step-Down Power µModule® Regulator DESCRIPTION Demonstration circuit 1780A-B features PolyPhase® design using the LTM®4620EV, the high efficiency, high density, dual 13A, switch mode step-down power module regulator. The input voltage is from 4.5V to 16V. The output voltage is jumper selectable from 1.0V to 2.5V. DC1780A-B can deliver nominal 75A output current with 3× LTM4620s in parallel. As explained in the data sheet, output current derating is necessary for certain VIN, VOUT, and thermal conditions. The LTM4620 on DC1780A-B always operates in continuous conduction mode. The switching frequency can be programmed through a resistor or can be synchronized to an external clock signal. The board allows the user to program how its output voltage ramps up and down through the TRACK_CONTROL pin. The output voltage is tightly regulated between VOUT+ and VOUT– through remote output voltage sensing which improves output voltage regulation at heavy loads. These features and the availability of the LTM4620EV in a compact 15mm × 15mm × 4.41mm LGA package make it ideal for use in many high density point-of-load regulation applications. The LTM4620 data sheet must be read in conjunction with this demo manual prior to working on or modifying the demo circuit DC1780A-B. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology, the Linear logo, μModule and PolyPhase are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. BOARD PHOTO Figure 1. 75A PolyPhase LTM4620/DC1780A-B Demo Board dc1780abfa 1 DEMO MANUAL DC1780A-B PERFORMANCE SUMMARY PARAMETER Specifications are at TA = 25°C CONDITIONS/NOTES VALUE Input Voltage Range 4.5V to 16V Output Voltage VOUT VIN = 4.5V to 16V, IOUT = 0A to 75A, JP4: 1.0V 1.0V ± 1.5% (0.985V to 1.015V) Maximum Continuous Output Current Derating is necessary for certain VIN, VOUT and thermal conditions, see data sheet for detail. 75A Default Operating Frequency 500kHz Resistor Programmable Frequency Range 400kHz to 780kHz External Clock Sync. Frequency Range 400kHz to 780kHz Efficiency VIN = 12V, VOUT = 1.0V, IOUT = 75A, fSW = 500kHz 80.6% See Figure 4 Load Transient VIN = 12V, VOUT = 1.0V, ISETP = 37.5A to 75A