Reliability

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In many applications TEC is a critical component because it affects the temperature of the whole device, can have an effect on its correct operation, and impact on heat dissipation.

Any TEC must provide a long operation life time without failure. Usually the required operation time must be in a range of 200,000 hours and longer.

RMT produces TE modules with required operation lifetime of 200,000-300,000 hours.

RMT provides whole range of tests for TECs (and TEC sub-mounts): qualifications testing and lot-to-lot control to confirm high reliability.

QUALIFICATIONS TESTING

Qualification testing is based on requirements of Telcordia GP-468-CORE (Reliability Assurance for Optoelectronic Devices).

TEST METHODS

Mechanical Shock	The test shall be performed according to MIL-STD-883 (Method 2002.4,Condition B). TECs are subjected to 1500 g level shock for pulse duration of 0.5 ms both directions in all three axis.
Vibration	The test shall be performed according to MIL-STD-883 (Method 2007.3,Condition A). TECs under the test are vibrated at variable frequency sequence (controlled from 20 to 2000 Hz and back down 20 Hz) four times in all three axis, peak acceleration of 20 g
Shear Force	The test shall be performed according to MIL-STD-883 (Method 2019).
High Temperature Storage	The test shall be performed for a minimum of 2000 hours at the TEC maximum-rating storage temperature.
Temperature Cycling	The test shall be performed according to MIL-STD-883 (Method 1010.8,Condition B). TECs are alternately exposed to environment temperatures of -55°C and +125°C with holding time of 10 minutes at each temperature. The test shall be preformed for at least 100 cycles.
Thermal Shock	The test shall be performed according to MIL-STD-883 (Method 1011.9,Condition A). TECs are alternately immersed in water kept at 0°C and +100°C with a 5 minute holding time at each temperature. This cycle is repeated 20 times
Intermittent Life	The test shall be performed according to MIL-STD-883 (Method 1006). The test shall be performed with ambient temperature equal to or greater than maximal operation temperature (i.e. 85°C). The TECs shall be cycled on and off for minimum of 5000 cycles. The duty cycle is 1.5 minutes on (during this time the TEC should reach at least 90% of DTmax) and 4.5 minutes off.
Steady State Life	The test shall be performed according to MIL-STD-883 (Method 1005.8). TECs are subjected to 125°C for a period 1000 hours while being powered by the maximum rated current.

SAMPLING PLAN

Sampling plan depends on application. Requirements of Telcordia GP-468-CORE standards are the most common. According to the GP-468-CORE a sample size corresponding to a Lot Tolerance Percent Defective Table (LTPD) of 10% is recommended at failure rate equal to zero (acceptance number C=0). It means SS=22 samples per test.

FAILURE CRITERIA

The suggested failure criteria for reliability tests are the following:

A change of 5% or higher in TEC Resistance
A change of 5% or hegher in TEC Figure-of-Merit
A drop in the TEC‘s maximum cooling capacity below its specified rate at the maximum operating temperature when measured with the maximum load.
A drop in the TEC‘s cooling capacity below its specified rate for a given current and temperature when measured under the maximum load

TESTING

Depending on an application a set of the above test methods and sampling plan are the subjects of modification.

RMT provides standard qualification testing of producing TECs as well as special test programs according to customer demand. Particularly for TEC sub-mounts the special test programs are required.

Here are only examples of Qualification Reports:

1ML06-023-09 Reliability Report (March 2003)	1MC06-060-10 Reliability Report (February 2004)
Complex Reliability Report 2008

LOT-TO-LOT CONTROL

RMT Test Lab. Visual Inspection

All 100% RMT manufactured TE modules and pass through detailed inspection. Lot-to-Lot control helps ensure the quality and reliability of individual lots.