DEMO MANUAL DC2481A-B LTM4677EY and LTM4650 Step-Down Module Regulator with PMBus Power System Management LTM4677 + 3 LTM4650, 186A DESCRIPTION 2 Demonstration circuit 2481A-B is a high efficiency, high LTCs I C/SMBus/PMBus dongle DC1613A to connect to density, Module regulator with 4.5V to 16V input range. the board. LTpowerPlay allows the user to reconfigure the The output voltage is adjustable from 0.5V to 1.8V, and it part on the fly and store the configuration in EEPROM, view can supply 186A maximum load current. The demo board telemetry of voltage, current, temperature and fault status has 1 LTM 4677 and 3 LTM4650 Module regulators. GUI Download The LTM4677 is a dual 18A or single 36A step-down regulator with PMBus power system management, and the The software can be downloaded from: LTM4650 is a dual 25A or single 50A step-down regulator. DEMO MANUAL DC2481A-B PERFORMANCE SUMMARY Specifications are at T = 25C A PARAMETER CONDITIONS VALUE Input Voltage Range 4.5V to 16V Output Voltage, V V = 4.5V to 16V, I = 0A to 186A 0.5 to 1.8V, Default: 1V OUT0 IN OUT0 Maximum Output Current, I V = 4.5V to 16V, V = 0.5V to 1.8V 186A OUT0 IN OUT Typical Efficiency V = 12V, V = 1.0V, I = 186A 85.8% IN OUT OUT Default Switching Frequency 425kHz QUICK START PROCEDURE NUMBER OF LTM4677 MODULE MAXIMUM OUTPUT CURRENT NUMBER OF OUTPUT VOLTAGES REGULATORS ON THE BOARD DEMO BOARD NUMBER Dual 18A 2 1 LTM4677 DC2066A 1 2 LTM4677 DC2143A-A 72A 1 3 LTM4677 DC2143A-B 108A 144A 1 4 LTM4677 DC2143A-C 86A 1 1 LTM4677 (+1LTM4650) DC2481A-A 186A 1 1 LTM4677 (+3LTM4650) DC2481A-B Demonstration circuit 2481A-B is easy to set up to evalu- Note: When measuring the output or input voltage ripple, ate the performance of the LTM4677EY. Refer to Figure 2 do not use the long ground lead on the oscilloscope probe. for the proper measurement equipment setup and follow See Figure 3 for the proper scope probe technique. Short, the procedure below. stiff leads need to be soldered to the (+) and () terminals of an output capacitor. The probes ground ring needs to 1. With power off, connect the input power supply to V IN touch the () lead and the probe tip needs to touch the (4.5V to 16V) and GND (input return). (+) lead. 2. Connect the 1.0V output load between V and GND OUT0 (Initial load: no load). Connecting a PC to DC2481A-B 3. Connect the DVMs to the input and outputs. Set default You can use a PC to reconfigure the power management switch position: SW1: ON SW2: ON. features of the LTM4677 such as: nominal V , margin OUT set points, OV/UV limits, temperature fault limits, sequenc- 4. Turn on the input power supply and check for the proper ing parameters, the fault log, fault responses, GPIOs and output voltages. V should be 1.0V 1%. OUT0 other functionality. The DC1613A dongle may be plugged 5. Once the proper output voltages are established, ad- when V is present. IN just the loads within the operating range and observe the output voltage regulation, ripple voltage and other parameters. 6. Connect the dongle and control the output voltages from the GUI. See LTpowerPlay Software GUI for details. dc2481abf 2