GEIA-SSB-1-C-2000.pdf
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1、T ua ua m EIA ENGINEERING BULLETIN Guidelines for Using Plastic Encapsulated Microcircuits and Semiconductors in Military, Aerospace and Other Rugged Applications SSB-1-C (Revision of SSB-1-B) ELECTRONIC INDUSTRIES ALLIANCE GOVERNMENT ELECTRONICS AND INFORMATION TECHNOLOGY ASSOCIATION A SECTOR OF Co
2、pyright Government Electronics distribution is wilunited. Copyright Government Electronics smaller package configurations allow higher circuit board packing density, therefore, reducing propagation delays Unit prices are lower than ceramic parts because of high volume, high yield, and high quality a
3、utomated manufacturing; cost benefits decrease with higher integration levels and pin counts due to the high price of die Devices are more readily available than hermetic devices due to market demand Unit price Availability The uncontrolled use of plastic encapsulated microcircuits and semiconductor
4、s can introduce a number of technical risks in military and aerospace equipment applications that are not associated with hermetic packaged devices. These potential risks include: Moisture ingress induced by humidity Electrolytic / galvanic corrosion, delamination and crack propagation induced by co
5、mbined effects of temperature cycling, humidity and bias conditions Outgassing of volatile substances induced by vacuum Device manufacturers characterize electrical performance over limited temperature ranges (e.9. Industrial Temperature Range: -40C to +85”C) “Popcorn” package cracks or in delaminat
6、ion induced by thermal effects during soldering Cumulative effects of mechanical and thermal stresses from assembly manufacturing, testing and service conditions on device long term reliability ii Copyright Government Electronics for power dissipation, calculate ATe; power dissipation can make pure
7、temperature cycling accelerated testing significantly inaccurate. All accelerated test cycles shall have temperature ramps c20C/min., and dwell times at temperature extremes shall be 15 minutes measured on the test boards. This will give -24 cycles/day. The failure/damage mechanism for solder change
8、s at lower temperatures; for assemblies seeing significant cold environment operations, additional “COLD” cycling from perhaps -4OOto OC with dwell times long enough for temperature equilibration and for a number of cycles equal to the “COLD” operational cycles in actual use is recommended. The fail
9、ure/damage mechanism for solder is different for large cyclic temperature swings transversing the stress-to-strain -20 to +2OoC transition region; for assemblies seeing such cycles in operation, additional appropriate “LARGE AT” testing with cycles similar in nature and number to actual use is recom
10、mended. 8 Copyright Government Electronics 20 years) Temperature Cycles Relative Humidity I up to 95% condensing I up to 95% condensing I I 7,305 (1 cycle per day; 20 years) IEquipment Life (Device Failure Rate) I 20 years I 300 FIT I 4.2.1 Service life Define the anticipated service life of the sys
11、tem and establish the acceptable Mean Time To Failure (MlTF) for the device. Allocate an acceptable failure rate (A) to the device and define the acceptable confidence level (a). 4.2.2 Temperature (Operating and Storage) Define the minimum and maximum temperature extremes the device will experience
12、in storage, shipment and in non-operating conditions. Define the maximum operating junction temperature of the device under consideration. It may be necessary to factor in the effects of heat sinking, cooling, loss of coolant, and other factors, as applicable. Failure rates should be estimated for e
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