SMJD-1V16W1P2 Datasheet, PDF (6/16 Pages) Seoul Semiconductor – Acrich2 - 100V 17W Downlight Connect using a AIC directly to AC power

2. Thermal Resistance of 17W
Part
Acrich2 LED
Acrich2 IC
Package Power
Dissipation [W]
SAW8KG0B Max 0.5
Max 1.5
Maximum Junction
Temp[℃]
125
125
Rθ_j-s
[℃/W]
27
5.5
Acrich2 LED, which has 27℃/W thermal resistance from junction to LED lead.
The maximum junction temperature of Acrich2 LED package is 125℃. So permissible max lead
temperature T_{s_max} is
T_{s_max} = T_{j_max} - (Rq_j-s * P_D)
= 125℃ - (27℃/W * 0.5W) = 111.5℃
But, Recommendation of LED lead temperature is under 70℃
Acrich2 IC, which has 5.5℃/W thermal resistance from junction to top surface.
The maximum junction temperature of its IC is 125℃. So allowable Acrich2 IC top surface
temperature (T_{t_max}) is
T_{t_max} = T_{j_max} - (y_j-t * P_D)
= 125℃ - (5.5℃/W * 1.5W) = 116.8℃
Rev. 03
November 2012
6
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