
SPEC NO: DSAK2938 REV NO: V.3 DATE: JUL/17/2010 PAGE: 6 OF 9
APPROVED: WYNEC CHECKED: Allen Liu DRAWN: Y.L.LI ERP: 1212000207
AT2117QB25Z1S-VFS
Heat Generation:
1.Thermal design of the end product is of paramount importance.Please consider the heat generation of the LED when making
the system design. The coefficient of temperature increase per input electric power is affected by the thermal resistance of the
circuit board and density of LED placement on the board ,as well as other components. It is necessary to avoid intense heat gen-
eration and operate within the maximum ratings given in this specification.
2.Please determine the operating current with consideration of the ambient temperature local to the LED and refer to the plot
of Permissible Forward current vs. Ambient temperature on CHARACTERISTICS in this specification. Please also take meas-
ures to remove heat from the area near the LED to improve the operational characteristics on the LED.
3.The equation
①
indicates correlation between T
j
and T
a
,and the equation
②
indicates correlation between T
j
and T
s
T
j
= T
a
+ R
thj-a
*W ………
①
Tj = T
s
+ R
thj-s
*W ………
②
Tj = dice junction temperature: °C
T
a
= ambient temperature:°C
T
s
= solder point temperature:°C
R
thj-a
= heat resistance from dice junction temperature to ambient temperature : °C / W
R
thj-s
= heat resistance from dice junction temperature to Ts measuring point : °C / W
W = inputting power (IFx VF) : W
Reflow soldering is recommended and the soldering profile is shown below.
Other soldering methods are not recommended as they might cause damage to the product.