PI3740-00 Datasheet, PDF (28/48 Pages) Vicor Corporation – Parallel capable with single wire current sharing

PI3740-00
Thermal Design Inductor
Figure 41 shows a thermal impedance model that can predict the maximum hot spot temperature of the inductor for a given operating
condition. This model assumes that all customer PCB connections are at one temperature, which is PCB equivalent Temperature T_PCB
°C. If the inductor top and bottom are not mounted to a heat sink, the simplified model is parallel combination of all resistances that
connect to the PCB.
Thermal Resistance
Inductor Case Top
ɸINT-TOP ^oC / W
Inductor Case Top
Temperature
TTOP ^oC
Maximum Internal Temperature
TINT ( ^oC )
Thermal Resistance
Inductor Case
BoƩom
ɸINT-BOT ^oC / W
Inductor Case
BoƩom
Temperature
TBOT ^oC / W
Thermal Resistances
Inductor PCB Pads
ɸINT-TAB
o_{C / W}
Inductor PCB Pad
Temperatures
TPCB-TAB
o_C
ɸINT-LEAD1
o_{C / W}
TPCB-LEAD1
o_C
ɸINT-LEAD2
o_{C / W}
TPCB-LEAD2
o_C
Figure 41 — PI3740-00 Inductor Thermal Impedance Model
Where the symbol in Figure 41 is defined as the following:
φ_INT-TOP
φ_INT-PCB
is defined as the thermal impedance from the hot spot to the top surface of the core.
is defined as the thermal impedance from the hot spot to the circuit board it is mounted on,
assuming all customer PCB connections are at one temperature.
φ_INT-BOT
is defined as the thermal impedance from the hot spot to the bottom surface of the core.
φ_INT-TAB
φ_INT-LEAD1
φ_INT-LEAD2
is defined as the thermal impedance from the hot spot to the metal mounting tab on the core body.
is defined as the thermal impedance from the hot spot to one of the mounting leads.
Since the leads are the same thermal impedance, there is no need to specify by explicit pin number
is defined as the thermal impedance from the hot spot to the other mounting lead
Cool-Power^® ZVS Switching Regulators
Page 28 of 48
Rev 1.4
04/2017
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