DLPC3433 datasheet(52/62 Pages) TI1

52 / 62 page

DLPC3433, DLPC3438

DLPS035B – FEBRUARY 2014 – REVISED JANUARY 2016

www.ti.com

11.2 Layout Example

Figure 27. Example Layout

11.3 Thermal Considerations

The underlying thermal limitation for the DLPC343x is that the maximum operating junction temperature (TJ) not

be exceeded (this is defined in the Recommended Operating Conditions). This temperature is dependent on

operating ambient temperature, airflow, PCB design (including the component layout density and the amount of

copper used), power dissipation of the DLPC343x, and power dissipation of surrounding components. The

DLPC343x’s package is designed primarily to extract heat through the power and ground planes of the PCB.

Thus, copper content and airflow over the PCB are important factors.

The recommended maximum operating ambient temperature (TA) is provided primarily as a design target and is

based on maximum DLPC343x power dissipation and RθJA at 0 m/s of forced airflow, where RθJA is the thermal

resistance of the package as measured using a glater test PCB with two, 1-oz power planes. This JEDEC test

PCB is not necessarily representative of the DLPC343x PCB; the reported thermal resistance may not be

accurate in the actual product application. Although the actual thermal resistance may be different, it is the best

information available during the design phase to estimate thermal performance. However, after the PCB is

designed and the product is built, TI highly recommended that thermal performance be measured and validated.

To do this, measure the top center case temperature under the worse case product scenario (max power

dissipation, max voltage, max ambient temperature) and validated not to exceed the maximum recommended

case temperature (TC). This specification is based on the measured φJT for the DLPC343x package and provides

a relatively accurate correlation to junction temperature. Take care when measuring this case temperature to

prevent accidental cooling of the package surface. TI recommends a small (approximately 40 gauge)

thermocouple. The bead and thermocouple wire should contact the top of the package and be covered with a

minimal amount of thermally conductive epoxy. The wires should be routed closely along the package and the

board surface to avoid cooling the bead through the wires.

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DLPC3433 Datasheet(PDF) 52 Page - Texas Instruments