Datasheet

LM20333
SNVS558D –MAY 2008–REVISED APRIL 2013 www.ti.com
Figure 33. Safe Thermal Operating Areas (I
OUT
= 3A, f
SW
= 500kHz)
Figure 34. Safe Thermal Operating Areas (I
OUT
= 3A, f
SW
= 750kHz)
Figure 35. Safe Thermal Operating Areas (I
OUT
= 2.5A, f
SW
= 500kHz)
The dashed lines in the figures above show an approximation of the minimum and maximum duty cycle
limitations; while, the solid lines define areas of operation for a given ambient temperature. This data for the
figure was derived assuming the device is operating at 3A continuous output current on a 4 layer PCB with a
copper area greater than 4 square inches exhibiting a thermal characteristic less than 27 °C/W. Since the
internal losses are dominated by the FETs a slight reduction in current by 500mA allows for much larger regions
of operation, as shown in Figure 35.
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