DC1379B: 3.3V @ 3A, 5.5 ~ 36V in, Inductor On-Chip

Summary

Demonstration circuit 1379B is a step-down DC/DC switching regulator featuring the LTM®8025 μModule® regulator. The demo board is designed to deliver a 3.3V output from a 5.5V to 36V input. The wide input range of the LTM8025 allows a variety of input sources such as automotive batteries, wall adaptors and industrial supplies.

The modes of operation (Burst Mode® operation or synchronization) are jumper-selectable. Burst Mode operation improves efficiency at light loads. The LTM8025 can be synchronized over a 250kHz to 2MHz range.

The current mode control scheme creates fast transient response and good loop stability. The RUN/SS pin can be used to set the part in micropower shutdown mode, reducing the supply current to less than 1μA. The RUN/SS pin can also be used to program soft-start. In this mode, the RUN/SS pin is driven through an external RC filter to create a voltage ramp on this pin reducing the input current surge during start-up.

The LTM8025 data sheet gives a complete description of the part, operation and applications information. The data sheet must be read in conjunction with this manual prior to working on or modifying demo circuit 1379B.

Specifications

Manufacturer	Analog Devices Inc.
Category	AC/DC and DC/DC Conversion
Sub-Category	DC/DC SMPS - Single Output
Eval Board Part Number	DC1379B-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	3.3 V
Current Out	3 A
Voltage In	5.5 ~ 36 V
Efficiency @ Conditions	>85%, 5.5V in, 3.3V @ 0.01 ~ 2.5 A >83%, 12V in, 3.3V @ 0.05 ~ 2.5 A >81%, 24V in, 3.3V @ 0.25 ~ 3 A >80%, 32V in, 3.3V @ 0.4 ~ 3 A
Voltage Out Range	0.8 ~ 24 V
Features	Current Limit (Adj. or Fixed) Current Sharing Power Good Output Shutdown, Enable, Standby Soft Start Synchronizable
Switching Frequency	200 kHz ~ 2.4 MHz
Standby Current [Typical]	10 nA
Quiescent Current [Typical]	25 µA
Component Count + Extras	9 + 21
Internal Switch	Yes
Design Author	Linear Technology
Application / Target Market	Automotive Point of Load (PoL) Portable Devices Power: Industrial Power
Standby Current [Maximum]	1 µA
Quiescent Current [Maximum]	60 µA
Main I.C. Base Part	LTM8025
Date Created By Author	2012-02
Date Added To Library	2013-12