3

oPErAting LiMits

The maximum current rating of the CMA3090 depends on the case temperature (Tc) when the LED has reached thermal equilibrium

under steady-state operation. The graphs shown below assume that the system design employs good thermal management (thermal

interface material and heat sink) and may vary when poor thermal management is employed. Either solder pad shown in the Mechanical

Dimensions section on page 18 can be used as the Tc measurement point.

Another important factor in good thermal management is the temperature of the Light Emitting Surface (LES). Cree recommends a

maximum LES temperature of 140 °C to ensure optimal LED lifetime. Please refer to the Thermal Design section on page 19 for more

information on LeS temperature measurement.

0

400

800

1200

1600

2000

2400

2800

3200

3600

4000

0

25

50

75

100

125

150

Case Temperature (°C)

48 V

85 °C, 3600 mA

125 °C, 1385 mA

CMA3090

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

0

25

50

75

100

125

150

Case Temperature (°C)

72 V

85 °C, 2400 mA

125 °C, 923 mA