LTM4630 datasheet(22/34 Pages) LINER

22 / 34 page

LTM4650

4650fb

For more information www.linear.com/LTM4650

readingsatdifferentinterfacesthatenablethecalculationof

theJEDEC-definedthermalresistancevalues;(3)themodel

and FEA software is used to evaluate the µModule with

heat sink and airflow; (4) having solved for and analyzed

these thermal resistance values and simulated various

operating conditions in the software model, a thorough

laboratory evaluation replicates the simulated conditions

with thermocouples within a controlled-environment

chamberwhileoperatingthedeviceatthesamepowerloss

as that which was simulated. An outcome of this process

and due-diligence yields a set of derating curves provided

in other sections of this data sheet. After these laboratory

test have been performed and correlated to the µModule

model, then the θJB and θBA are summed together to cor-

relate quite well with the µModule model with no airflow or

heat sinking in a properly define chamber. This θJB + θBA

value is shown in the Pin Configuration section and should

accurately equal the θJA value because approximately

100% of power loss flows from the junction through the

board into ambient with no airflow or top mounted heat

sink. Each system has its own thermal characteristics,

therefore thermal analysis must be performed by the user

in a particular system.

APPLICATIONS INFORMATION

The LTM4650 module has been designed to effectively

remove heat from both the top and bottom of the pack-

age. The bottom substrate material has very low thermal

resistance to the printed circuit board. An external heat

sink can be applied to the top of the device for excellent

heat sinking with airflow.

Figure 10 shows a temperature plot of the LTM4650 with

12V input, 1.0V output at 50A without heat sink and a no

airflow condition.

Safety Considerations

The LTM4650 modules do not provide isolation from VIN

to VOUT. There is no internal fuse. If required, a slow blow

fuse with a rating twice the maximum input current needs

to be provided to protect each unit from catastrophic

failure. The device does support over current protection.

A temperature diode is provided for monitoring internal

temperature,andcanbeusedtodetecttheneedforthermal

shutdown that can be done by controlling the RUN pin.

Figure 10. Thermal Image 12V to 1V, 50A with No Air Flow and No Heat Sink (Based on 4-Layer

101mm × 114mm PCB Board Containing 2oz Copper on the Top, Bottom and All Internal Layers)

LTM4630 Datasheet(PDF) 22 Page - Linear Technology

LTM4630 Datasheet(HTML) 22 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

Datasheet Download

Link URL