DC1780A-B: 1V @ 75A, 4.5 ~ 16V in, Buck

Summary

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.

Specifications

Manufacturer	Analog Devices Inc.
Category	AC/DC and DC/DC Conversion
Sub-Category	DC/DC SMPS - Single Output
Eval Board Part Number	DC1780A-B-ND
Eval Board Supplier	Analog Devices Inc.
Eval Board	Normally In Stock
Topology	Step Down
Outputs and Type	1 Non-Isolated
Voltage Out: Factory Set	1 V
Current Out	75 A
Voltage In	4.5 ~ 16 V
Efficiency @ Conditions	>92%, 5V in, 2.5V @ 15 ~ 75 A >90%, 5V in, 1.8V @ 15 ~ 75 A >88%, 5V in, 1.5V @ 12 ~ 75 A >86%, 5V in, 1.2V @ 10 ~ 75 A >85%, 12V in, 2.5V @ 20 ~ 75 A >84%, 12V in, 1.8V @ 20 ~ 75 A >83%, 12V in, 1.5V @ 20 ~ 75 A >82%, 5V in, 1.0V @ 9 ~ 75 A >82 %, 12V in, 1.2V @ 20 ~ 75 A >80%, 12V in, 1.0V @ 20 ~ 75 A
Voltage Out Range	0.5 ~ 2.5 V
Features	Current Limit (Adj. or Fixed) Over Current Protection Over Voltage Protection Power Good Output Shutdown, Enable, Standby Synchronizable Thermal Protection Under Voltage Protection, Brown-Out Voltage Tracking
Switching Frequency	400 ~ 780 kHz
Standby Current [Typical]	50 µA
Quiescent Current [Typical]	5 mA
Component Count + Extras	36 + 91
Internal Switch	Yes
Design Author	Linear Technology
Application / Target Market	Memory Back-up Networking Power: Industrial Power Telecom
Standby Current [Maximum]	- Not Given
Quiescent Current [Maximum]	65 mA
Main I.C. Base Part	LTM4620
Date Created By Author	2011-12
Date Added To Library	2016-03