SnapLED 70 Emitter Reliability Datasheet RD05 (3/04)

2

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85

110

23,000

4.314

10,000

9.932

75

100

33,000

3.044

14,000

7.009

65

90

47,000

2.107

21,000

4.852

55

80

70,000

1.429

30,000

3.289

45

70

106,000

0.947

46,000

2.180

35

60

163,000

0.612

71,000

1.410

25

50

259,000

0.385

113,000

0.887

N

No

otte

es

s::

[1]

The point typical MTBF (which represents 60% confidence level) is the total device hours divided by the number of failures. In the case of

zero failures, one failure is assumed for this calculation.

[2]

The 90% Confidence MTBF represents the minimum level of reliability performance which is expected from 90% of all samples. This confi

dence interval is based on the statistics of the distribution of failures. The assumed distribution of failures is exponential. This particular

distribution is commonly used in describing useful life failures. Refer to MILSTD690B for details on this methodology.

[3]

A failure is any LED which does not emit light and max. % Iv degradation is > 50%.

[4]

Assuming 115°C/W of

θJA

Example of Failure Rate Calculation

Assume a device operating 8 hours/day, 5 days/week. The utilization factor, given 168 hours/week is:

(8 hours/day) x (5 days/week) / (168 hours/week) = 0.25

The point failure rate per year (8760 hours) at 25°C ambient temperature is:

(0.060% / 1K hours) x (0.25) x (8760 hours/year) = 0.131% per year

Similarly, 90% confidence level failure rate per year at 25°C:

(0.137% / 1K hours) x (0.25) x (8760 hours/year) = 0.300% per year

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Temperature Cycle

MILSTD883

55

°C to 100°C, 15 min. dwell, 5 min. transfer

Method 1010

20 cycles

6090

0

100 cycles

6090

0

Temperature Cycle

MILSTD883

40

°C to 120°C, 15 min. dwell, 5 min. transfer

Method 1010

20 cycles

1071

0

100 cycles

1071

0

Power Temperature

Internal

40

°C to 85°C, 18 min. dwell, 42 min. transfer,

Cycle

Reference

70 mA, 5 min on/off

100 cycles

98

0