NCP1060, NCP1063
www.onsemi.com
28
Power Dissipation and Heatsinking
The NCP106X welcomes two dissipating terms, the DSS
current−source (when active) and the MOSFET. Thus, P
tot
= P
DSS
+ P
MOSFET
. It is mandatory to properly manage the
heat generated by losses. If no precaution is taken, risks exist
to trigger the internal thermal shutdown (TSD). To help
dissipating the heat, the PCB designer must foresee large
copper areas around the package. Take the PDIP−7 package
as an example, when surrounded by a surface approximately
200 mm
2
of 35 mm copper, the maximum power the device
can thus evacuate is:
P
max
+
T
Jmax
* T
ambmax
R
qJA
(eq. 10)
which gives around 870 mW for an ambient of 50°C and a
maximum junction of 150°C. If the surface is not large
enough, the R
θ
JA
is growing and the maximum power the
device can evacuate decreases. Figure 49 gives a possible
layout to help drop the thermal resistance.
Figure 49. A Possible PCB Arrangement to Reduce the Thermal Resistance Junction−to−Ambient
Bill of material:
C1 Bulk capacitor, input DC voltage is connected to the capacitor
C2, R1, D1 Clamping elements
C3 Vcc capacitor
OK1 Optocoupler
R2 Resistor to setting I
PEAK
current
Table 5. ORDERING INFORMATION
Device Frequency R
DS(on)
Brown In Package Type Shipping
NCP1060AP060G 60 kHz 34 Yes
PDIP−7
(Pb−Free)
50 Units / Rail
NCP1060AP100G 100 kHz 34 Yes 50 Units / Rail
NCP1060AD060R2G 60 kHz 34 Yes
SOIC−10
(Pb−Free)
2500 / Tape & Reel
NCP1060AD100R2G 100 kHz 34 Yes 2500 / Tape & Reel
NCP1060BD060R2G 60 kHz 34 No 2500 / Tape & Reel
NCP1060BD100R2G 100 kHz 34 No 2500 / Tape & Reel
NCP1063AP060G 60 kHz 11.4 Yes
PDIP−7
(Pb−Free)
50 Units / Rail
NCP1063AP100G 100 kHz 11.4 Yes 50 Units / Rail
NCP1063AD060R2G 60 kHz 11.4 Yes
SOIC−16
(Pb−Free)
2500 / Tape & Reel
NCP1063AD100R2G 100 kHz 11.4 Yes 2500 / Tape & Reel
