3

oPEraTing LiMiTs

The maximum current rating of the CMT1925 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.

CMT1925 - Standard

0

100

200

300

400

500

600

700

800

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

0

25

50

75

100

125

150

Case Temperature (°C)

85 °C, 1700 mA

125 °C,

654 mA

Standard LEDs

CMT1925 - eTone

0

100

200

300

400

500

600

700

800

900

1000

0

25

50

75

100

125

150

Case Temperature (°C)

eTone LEDs

85 °C, 910 mA