DEMO MANUAL DC1811B-B LTM4676A Dual Step-Down Module Regulator with PMBus Digital Power System Management DESCRIPTION 2 PC and use ADIs I C/SMBus/PMBus dongle DC1613A Demonstration circuit 1811B-B is a dual-output, high to connect to the board. LTpowerPlay allows the user to efficiency, high density, Module regulator with 4.5V to reconfigure the part on-the-fly and store the configuration 26.5V input range. Each output can supply 13A maximum in EEPROM, view telemetry of voltage, current, tempera- load current. The demo board has a LTM 4676A Module ture and fault status. regulator, which is a dual 13A or single 26A step-down regulator with PMBus power system management. Please GUI Download see LTM4676A data sheet for more detailed information. The software can be downloaded from: LTpowerPlay The DC1811B-B powers up to default settings and pro- duces power based on configuration resistors without For more details and instructions of LTpowerPlay, please refer the need for any serial bus communication. This allows to LTpowerPlay GUI for LTM4676A Quick Start Guide. easy evaluation of the DC/DC converter. To fully explore Design files for this circuit board are available. the extensive power system management features of the part, download the GUI software LTpowerPlay onto your All registered trademarks and trademarks are the property of their respective owners. BOARD PHOTO Figure1. Dual-Output LTM4676A/DC1811B-B Demo Circuit Rev. A 1DEMO MANUAL DC1811B-B PERFORMANCE SUMMARY (T = 25C) A PARAMETER CONDITION VALUE Input Voltage Range 4.5V to 26.5V Output Voltage, V V = 4.5V to 26.5V, I = 0A to 13A 0.5V to 5.5V (Minimum On)*, Default: 1V OUT0 IN OUT0 Maximum Output Current, I V = 4.5V to 26.5V, V = 0.5V to 5.5V 13A OUT0 IN OUT Output Voltage, V V = 4.5V to 26.5V, I = 0A to 13A 0.5V to 5.5V (Minimum On)*, Default: 1.8V OUT1 IN OUT1 Maximum Output Current, I V = 4.5V to 26.5V, V = 0.5V to 5.5V 13A OUT1 IN OUT Typical Efficiency V = 12V, V = 1.8V, I = 13A 86.3% IN OUT OUT Default Switching Frequency 500kHz *For low duty cycle applications, it may approach minimum on the limit. The minimum on-time for LTM4676A is 45ns nominal, guardband to 90ns. QUICK START PROCEDURE Table 1. LTM4676/LTM4676A Demo Cards for Up to 130A Point-of-Load Regulation NUMBER OF LTM4676/LTM4676A MODULE MAXIMUM OUTPUT CURRENT NUMBER OF OUTPUT VOLTAGES REGULATORS ON THE BOARD DEMO BOARD NUMBER 13A, 13A 2 1 LTM4676 DC1811A/DC1811B-A 13A, 13A 2 1 LTM4676A DC1811B-B 26A 1 1 LTM4676 DC2087A 50A 1 2 LTM4676 DC1989A-A 75A 1 3 LTM4676 DC1989A-B 100A 1 4 LTM4676 DC1989A-C 100A 1 1 LTM4676 (+ 3 LTM4620A) DC2106A-A 130A 1 1 LTM4676 (+ 3 LTM4630) DC2106A-B Demonstration circuit 1811B-B is easy to set up to evalu- 7. Connect the dongle and control the output voltages ate the performance of the LTM4676A. Refer to Figure2 from the GUI. See LTpowerPlay GUI for the LTM4676A for the proper measurement equipment setup and follow Quick Start Guide for details. the procedure below. Note: When measuring the output or input voltage rip- 1. With power off, connect the input power supply to V ple, do not use the long ground lead on the oscilloscope IN (4.5V to 26.5V) and GND (input return). probe. See Figure3 for the proper scope probe technique. Short, stiff leads need to be soldered to the (+) and () 2. Connect the 1.0V output load between V and GND OUT0 terminals of an output capacitor. The probes ground ring (Initial load: no load). needs to touch the () lead and the probe tip needs to 3. Connect the 1.8V output load between V and GND OUT1 touch the (+) lead. (Initial load: no load). 4. Connect the DVMs to the input and outputs. Set default Connecting a PC to DC1811B-B jumper position: JP1: ON JP2: ON. You can use a PC to reconfigure the power management 5. Turn on the input power supply and check for the features of the LTM4676A such as: nominal V , mar- OUT proper output voltages. V should be 1.0V 0.5 %, gin set points, OV/UV limits, temperature fault limits, OUT0 and V should be 1.8V 0.5%. sequencing parameters, the fault log, fault responses, OUT1 GPIOs and other functionality. The DC1613A dongle may 6. Once the proper output voltages are established, adjust the be plugged when V is present. loads within the operating range and observe the output IN voltage regulation, ripple voltage and other parameters. Rev. A 2