Every MI Family module undergoes extensive post-production environmental stress screening (ESS) before shipment to verify compliance with Vicor's high quality and performance standards and to eliminate early life failures.

The current program of unpowered temperature cycling and dynamic power cycling burn-in is the result of years of test data analysis, process improvement, and screening strength calculations based on DOD-HDBK-344A, Hughes Model RADC-TR-86-149, and IES ESSEH Guidelines. To ensure the most effective routine for precipitating module failures, Vicor continually evaluates its ESS program and makes appropriate changes as new data become available or as product improvements occur. After burn-in and temperature cycling, each module undergoes final electrical testing over the specified temperature range. The program is outlined below.

MI Family Module Screening	I Grade	M Grade
Operating Temperature MI-200: MI-J00:	-40°C to +85°C -40°C to +100°C	-55°C to +85°C -55°C to +100°C
Storage Temperature MI-200: MI-J00:	-55°C to +100°C -55°C to +125°C	-65°C to +100°C -65°C to +125°C
Temperature Cycling 17°C per minute nominal rate of change, dwell time until product stabilization.	12 cycles -65°C to +100°C	12 cycles -65°C to +100°C
Ambient Test @ 25°C	Yes	Yes
Power Cycling Burn-In Power on 10 min., off 15 min. Module temperature cycling 35°C to 80°C Load up to 100W Module output continuously monitored while enabled	12 hours, 29 cycles	96 hours, 213 cycles
Functional and Parametric ATE Tests Low & high temp.	-40°C to +85°C	-55°C to +85°C
AC Hi-Pot Test	Yes	Yes
Visual Inspection Before packing into ESD containers.	Yes	Yes

Because operating temperature is one of the most important factors in determining overall module reliability, it is imperative that the user's system design allow for efficient heat transfer from the baseplate to system ambient. Since temperature and failure rate are exponentially related, just a 10°C decrease in baseplate temperature can have a dramatic increase in MTBF. Due to patented zero-voltage/zero-current switching topology, Vicor converters are highly efficient compared to those with more traditional topologies. High efficiency translates into both smaller size and lower temperature rises. To minimize thermal impedance, all major power dissipating components are mounted directly to the baseplate.

Below are representative calculated MTBF values based on MIL-HDBK-217F. If you require information about a specific model, contact Vicor with the model number, expected baseplate temperature, and operating environment to obtain an individually prepared report.

Model No.	Baseplate Temperature	MTBF in 1000 hrs.
		G.B.	G.F.	A.I.C.	N.S.
MI-J21-MY	25°C	3,619	1,810	1,086	1,068
	50°C	2,208	1,104	662	651
	65°C	1,701	851	510	502
MI-221-MW	25°C	3,277	1,634	983	966
	50°C	1,999	999	599	590
	65°C	1,540	770	462	454

Fully encapsulated, Vicor's MI Family modules utilize a proprietary spin fill process that assures complete, void free encapsulation making them suitable for the most harsh environments. In addition to providing mechanical rigidity, the encapsulant is thermally conductive to eliminate hot spots and aid in heat transfer to the baseplate. Two grades, I & M, are available with temperatures to -55°C operating and -65°C storage.

To verify the suitability of Vicor's MI Family products for harsh environments, MI Family modules have been subjected to the environmental testing requirements of MIL-STD-810 and MIL-STD-202. These tests, listed below, are performed at an independent laboratory. Additional environmental tests can be done upon individual customer request. Some of those performed for specific customer applications include ESD (DOD-HDBK-263), Structure Borne (Acoustic) Noise, Transportation Vibration, Flammability, Terminal Strength, Thermal Shock, and Power Conditioning. Contact the factory for details.

• MIL-STD-810D, Method 500.2, Proc III, explosive decompression (40Kft.).
• MIL-STD-810D, Method 500.2, Proc II, 40,000 ft., 1000-1500 ft./min. to 70,000 ft., unit functioning.

MIL-STD-810C, Method 511.1, Proc I.

• MIL-STD-810D, Method 514.3, Proc I, Category 6, Helicopter, 20 G's.
• MIL-STD-810D, Method 514 Random: 10-300Hz @ .02g 2 /Hz, 2000Hz @ .002 2 /Hz, 3.9 total Grms 3 hours/axis. Sine: 30Hz @ 20g's, 60Hz @ 10 g's, 90Hz @ 6.6g's, 120Hz @ 5.0g's, 16.0 total Grms, 3 axes.
• MIL-STD-810E, Method 514.4, table 514.4-VII, ±6db/octave, 7.7Grms, 1hr/axis.

• MIL-STD-810D, Method 516.3, Proc. I, Functional Shock, 40 G's.
• MIL-STD-202, Method 213, 18 pulses, 60 G's, 9msec.
• MIL-STD-202, Method 213, 75G, 11ms Saw Tooth Shock.
• MIL-STD-202, Method 207, 3 impacts/axis, 1,3,5 feet.

MIL-STD-810D, Method 513.3, Proc. II operational test, 9 G's for 1 minute along 3 mutually perpendicular axes.

MIL-STD-810D, Method 507.2, Proc I, Cycle I, 240 hrs, 88% relative humidity.

MIL-STD-202, Method 208, 8 hr. aging.

MIL-STD-810C, Method 508.

MIL-STD-810C, Method 509.1.