LM5112

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SNVS234B – SEPTEMBER 2004 – REVISED APRIL 2006

where

•

(1)

Therefore, the power dissipation in the driver due to charging and discharging of MOSFET gate capacitances at

(2)

In addition to the above gate charge power dissipation, - transient power is dissipated in the driver during output

interval of time through the output totem-pole N and P channel MOSFETs. The final component of power

dissipation in the driver is the power associated with the quiescent bias current consumed by the driver input

stage and Under-voltage lockout sections.

Characterization of the LM5112 provides accurate estimates of the transient and quiescent power dissipation

components. At 300 kHz switching frequency and 30 nC load used in the example, the transient power will be 8

Therefore the total power dissipation

(3)

We know that the junction temperature is given by

(4)

Or the rise in temperature is given by

(5)

For WSON-6 package, the integrated circuit die is attached to leadframe die pad which is soldered directly to the

printed circuit board. This substantially decreases the junction to ambient thermal resistance (

suitable means of heat dispersion from the IC to the ambient through exposed copper pad, which can readily

dissipate heat to the surroundings,

for the driver example above is thereby reduced to just 5.5 degrees.

(6)

For MSOP-PowerPAD

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