Demonstration circuit 2924A-A/2924A-B features the LTM4681: the wide input and output voltage range, high efficiency and power density, quad output PolyPhase® DC/DC step-down μModule® regulator with digital power system management. Demo board DC2924A is available in two versions: DC2924A-A is configured as 4-phase 4 outputs, DC2924A-B is configured as 4-phase single output. The demo board default input voltage range is 4.5V to 16V. However, if VIN is lower than 6V and within 4.5V ≤ VIN ≤ 5.75V range, minor modification to certain existing onboard components is required. Please refer to the Operation at Low VIN: 4.5V ≤ VIN ≤ 5.75V paragraph in the demo manual for more details. The factory default output voltage (VOUT0, VOUT1, VOUT2 and VOUT3) is 1V at 30A maximum load current per channel (DC2924A-A). The factory default output voltage VOUT = 1V at 120A maximum load current (DC2924A-B). Each channel can deliver up to 30A maximum load current but forced airflow and heat sink might also be used to further optimize the output power when all output rails are on and fully loaded. The demo board output voltages can be adjusted from 0.6V up to 1.8V. Programming the output voltages to any value that is greater than 1.8V, requires derating output current based on thermal derating curves provided in the LTM4681 data sheet. The factory default switching frequency is preset at 350kHz typical. Both versions of DC2924A come with PMBus interface and digital power system management functions. An onboard 12-pin connector is available for users to connect the dongle DC1613A to the demo board, provides an easy way to communicate and program the part using LTpowerPlay® software development tool. LTpowerPlay software and I2C/PMBus/SMBus dongle DC1613A allows users to monitor real time telemetry of input and output voltages, input and output current, switching frequency, internal IC die temperatures, external power component temperatures and fault logs. Programmable parameters include device address, output voltages, control loop compensation, switching frequency, phase interleaving, DCM or CCM mode of operation, digital soft-start, sequencing and time based shutdown, fault responses to input and output overvoltage, output overcurrent, IC die and power component overtemperatures.
The LTM4681 is available in a thermally enhanced, low profile 330-Lead (15mm × 22mm × 8.17mm) BGA package. It is recommended to read the LTM4681 data sheet and the 2924A-A/2924A-B demo manual prior to use or making any hardware changes to DC2924A-A/DC2924A-B.