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Progressive stress—a new accelerated approach to voltage endurance
156
ABSTRACTS
ON ELECTRONIC
COMPONENTS,
MATERIALS
AND
TECHNIQUES
S t a t i s t i c a l p r o c e d u r e s for c i r c u i t s - p a r t s s e l e c t i o n . E. E. BREWER, EIectromech. Des@, 6, 42-51 (1962). Reviews m e t h o d s of statisticai analysis d u r i n g the d e v e l o p m e n t stage to see the effects of variations in part-parameters. R e d u n d a n c y a n d s w i t c h i n g f a i l u r e . H. S. BAL~.B.~._',',E/eetron. Desi;,n 10, 72-75 /1962). T h e a s s u m p t i o n that the switching is failure-free in s t a n d b y r e d u n d a n t circuits is not necessarily justified. Six practical a s s u m p t i o n s are m a d e to simplify the analysis. S t a n d b y r e d u n d a n c y is a s s u m e d with a m o n i t o r to decide w h e n to switch. E x p r e s s i o n s for the reliability are developed a n d the usual exponential a s s u m p t i o n s are made. T h e results s h o w that the reliability cannot exceed that of the monitor. T h e A i r F o r c e a p p r o a c h to r e l i a b i l i t y i n b a l l i s t i c m i s s i l e w e a p o n s y s t e m s . * V. J. B ~ c H a , Planet. Space Sci. 7, 20S-216 (1961). T h e Air Force Ballistic Missile Division's concept and a p p r o a c h to reliability broadly covers the reliability r e q u i r e m e n t s for a ballistic missile weapon s y s t e m a n d t h e factors involved. T h e p r o c e d u r e s which ballistic missile contractors follow in attaining the required reliability are also given. T e c h n i q u e s i n t h e d e m o n s t r a t i o n o f r e l i a b i l i t y a t t a i n m e n t . * E. D. K.~R.~UOL and J. S. YOL'TCrtEFF, Planet. Space Sci. 7, 230-241 (1961). Describes the analytical t e c h n i q u e s w h i c h are being utilized in the d e m o n s t r a t i o n o f e q u i p m e n t reliability in a re-entry vehicle s y s t e m d e v e l o p m e n t p r o g r a m m e . A n a l y s i s o f r a n d o m f a i l u r e s . * G. P. Axt>zRso.-,- a n d L. E. PETee,SO.X', Planet. Space Sci. 7, 242-253 (1961). T h i s paper shows h o w the analysis of r a n d o m failures has been used in p r o d u c t i m p r o v e m e n t at R e m i n g t o n R a n d Univac, and s o m e of the t e c h n i q u e s empIo.ved in the analysis of c o m p u t e r sealed chassis and c o m p o n e n t part failures are described. P r o g r e s s i v e s t r e s s ~ a n e w a c c e l e r a t e d a p p r o a c h to v o l t a g e e n d u r a n c e , x,V. T . STaRR a n d H. S. ESDICOT-r, Trans. A.I.E.E. 55, Pt. I l L pp. 515-522 (1961). T h e paper analyses an accelerated e n d u r a n c e test that uses stresses which increase with time. T e s t results are s h o w n for M y l a r and a s p h a l t - m i c a composite, A n a p p e n d i x reviews t h e use of progressive stress testing in other fields. A s t a t u s r e p o r t o n e q u i p m e n t r e l i a b i l l t y - - a n e w a p p r o a c h is i n d i c a t e d . L. LaXDe,E',', .llissiles and Space 7, 20-23 (1961). T h e Atlas c o m p u t e r s have a m e a n - t i m e - b e t w e e n - f a i l u r e s of over 250 hr, m o r e than five times the contractual r e q u i r e m e n t . It is c o n c l u d e d that: solid state circuitry operates better with no s h u t d o w n s a n d can be extremely reliable; m a i n t e n a n c e degrades reliability to s o m e degree; diagnostic p r o c e d u r e s are best for preventive maintenance. Reliability in space, d u e largely to space/weight limitations a n d to the adverse e n v i r o n m e n t , presents more difficult problems. T h e m o s t p r o m i s i n g field is that of d e t e r m i n i n g the m e c h a n i s m of failure in each case and then finding ways to m e a s u r e a n d reduce it. T h i s will p e r m i t m o r e accurate accclerated testing of c o m p o n e n t s . Molecular electronics does not s e e m to be the a n s w e r at present. R e a c t i o n s w i t h d i p - s o l d e r i n g o f p r i n t e d c i r c u i t s . * (In G e r m a n . ) G. L.~,b'B.XtZVER, Radio 3[entor 27, No. 12, 1010-1015 (1961). T h e factors w h i c h govern dip-soldering" of p r i n t e d circuits are discussed. E x p e r i m e n t a l data o f d i p p i n g time against t e m p e r a t u r e and m e a s u r e m e n t s of the t e m p e r a t u r e rise with time, are described.
RELIABILITY OF COMPONENTS,
TUBES AND TRANSISTORS
E f f e c t s o f t e m p e r a t u r e o n h i g h - f r e q u e n c y t r a n s i s t o r s . C. R. Grc~v and T . C. SOWERS, Electro-Technology, July 1962. Variations in the parameters, power gain, b a n d w i d t h , noise figure, p o w e r o u t p u t and f r e q u e n c y shift are caused by t e m p e r a t u r e changes in the h i g h - f r e q u e n c y g e r m a n i u m diffused-base transistor. A n u m b e r of m e a s u r e m e n t s have been m a d e w h i c h relate h i g h - f r e q u e n c y transistor p a r a m e t e r s to a m b i e n t t e m p e r a t u r e ranges f r o m - - 6 0 ° to 80~C. M e a s u r e m e n t o f s e m i c o n d u c t o r c o m p o n e n t p a r t s i n m a n u f a c t u r e . (In G e r m a n . ) G. F.~BE.XDER, Nachrichtentechnik 13, No. 1, p. 16 (1963). A m a n u f a c t u r e of desired types of s e m i c o n d u c t o r c o m p o n e n t parts is still impossible today. Therefore, the different types m u s t be obtained o u t of a whole m a n u f a c t u r e d series by m e a s u r e m e n t . T h i s requires special h i g h - s p e e d m e a s u r i n g i n s t r u m e n t s , w h o s e function is described in the article. D e s i g n a n d c o n s t r u c t i o n o f a n a u t o m a t i c t r a n s i s t o r t e s t i n g a n d s o r t i n g m a c h i n e . (In G e r m a n . ) H. TILCX~R, .Vachrichtentechnik 13, "No. 1, p. 23 (1963). A n a u t o m a t i c m a c h i n e is described w h i c h is designed to test L . F . transistors of low power. T h e m a c h i n e possesses a capacity of 1000 pieces;hr and classes according to types and causes of rejection. T h e highest possible n u m b e r of yes-no m e a s u r e m e n t s is 28 with 36 types including rejects. T h e e l e c t r i c a l p r o t e c t i o n o f s e m i c o n d u c t o r d e v i c e s i n t h e l i g h t o f a v a i l a b l e d a t a . G. D. PER~qI>'S, Brit. Communicat. Electron., July 1962. A short rdsum6 of the different kinds of faults w h i c h o c c u r and the necessary data to enable the circuit protection engineer to make his own calculations a n d choose appropriate protective devices. c o m p o n e n t a n a l y s i s u t i l i z i n g s h o r t - t e r m m a t e r i a l s a n d d e s i g n s t u d i e s . \V. E. DCNKV-L, Proc. Sth National Syrup. on Reliability and Quality Control, W a s h i n g t o n , D.C., Jan. 1962, pp. 520-523. Describes h o w
Long-term
tests of short duration can be used to predict the life of electronic c o m p o n e n t s u s i n g accelerated life tests. * Based on Electrical Engineering Abstracts by kind permigsion of T h e I n s t i t u t i o n of Electrical Engineers.
ABSTRACTS
ON ELECTRONIC
COMPONENTS,
MATERIALS
AND
TECHNIQUES
S t a t i s t i c a l p r o c e d u r e s for c i r c u i t s - p a r t s s e l e c t i o n . E. E. BREWER, EIectromech. Des@, 6, 42-51 (1962). Reviews m e t h o d s of statisticai analysis d u r i n g the d e v e l o p m e n t stage to see the effects of variations in part-parameters. R e d u n d a n c y a n d s w i t c h i n g f a i l u r e . H. S. BAL~.B.~._',',E/eetron. Desi;,n 10, 72-75 /1962). T h e a s s u m p t i o n that the switching is failure-free in s t a n d b y r e d u n d a n t circuits is not necessarily justified. Six practical a s s u m p t i o n s are m a d e to simplify the analysis. S t a n d b y r e d u n d a n c y is a s s u m e d with a m o n i t o r to decide w h e n to switch. E x p r e s s i o n s for the reliability are developed a n d the usual exponential a s s u m p t i o n s are made. T h e results s h o w that the reliability cannot exceed that of the monitor. T h e A i r F o r c e a p p r o a c h to r e l i a b i l i t y i n b a l l i s t i c m i s s i l e w e a p o n s y s t e m s . * V. J. B ~ c H a , Planet. Space Sci. 7, 20S-216 (1961). T h e Air Force Ballistic Missile Division's concept and a p p r o a c h to reliability broadly covers the reliability r e q u i r e m e n t s for a ballistic missile weapon s y s t e m a n d t h e factors involved. T h e p r o c e d u r e s which ballistic missile contractors follow in attaining the required reliability are also given. T e c h n i q u e s i n t h e d e m o n s t r a t i o n o f r e l i a b i l i t y a t t a i n m e n t . * E. D. K.~R.~UOL and J. S. YOL'TCrtEFF, Planet. Space Sci. 7, 230-241 (1961). Describes the analytical t e c h n i q u e s w h i c h are being utilized in the d e m o n s t r a t i o n o f e q u i p m e n t reliability in a re-entry vehicle s y s t e m d e v e l o p m e n t p r o g r a m m e . A n a l y s i s o f r a n d o m f a i l u r e s . * G. P. Axt>zRso.-,- a n d L. E. PETee,SO.X', Planet. Space Sci. 7, 242-253 (1961). T h i s paper shows h o w the analysis of r a n d o m failures has been used in p r o d u c t i m p r o v e m e n t at R e m i n g t o n R a n d Univac, and s o m e of the t e c h n i q u e s empIo.ved in the analysis of c o m p u t e r sealed chassis and c o m p o n e n t part failures are described. P r o g r e s s i v e s t r e s s ~ a n e w a c c e l e r a t e d a p p r o a c h to v o l t a g e e n d u r a n c e , x,V. T . STaRR a n d H. S. ESDICOT-r, Trans. A.I.E.E. 55, Pt. I l L pp. 515-522 (1961). T h e paper analyses an accelerated e n d u r a n c e test that uses stresses which increase with time. T e s t results are s h o w n for M y l a r and a s p h a l t - m i c a composite, A n a p p e n d i x reviews t h e use of progressive stress testing in other fields. A s t a t u s r e p o r t o n e q u i p m e n t r e l i a b i l l t y - - a n e w a p p r o a c h is i n d i c a t e d . L. LaXDe,E',', .llissiles and Space 7, 20-23 (1961). T h e Atlas c o m p u t e r s have a m e a n - t i m e - b e t w e e n - f a i l u r e s of over 250 hr, m o r e than five times the contractual r e q u i r e m e n t . It is c o n c l u d e d that: solid state circuitry operates better with no s h u t d o w n s a n d can be extremely reliable; m a i n t e n a n c e degrades reliability to s o m e degree; diagnostic p r o c e d u r e s are best for preventive maintenance. Reliability in space, d u e largely to space/weight limitations a n d to the adverse e n v i r o n m e n t , presents more difficult problems. T h e m o s t p r o m i s i n g field is that of d e t e r m i n i n g the m e c h a n i s m of failure in each case and then finding ways to m e a s u r e a n d reduce it. T h i s will p e r m i t m o r e accurate accclerated testing of c o m p o n e n t s . Molecular electronics does not s e e m to be the a n s w e r at present. R e a c t i o n s w i t h d i p - s o l d e r i n g o f p r i n t e d c i r c u i t s . * (In G e r m a n . ) G. L.~,b'B.XtZVER, Radio 3[entor 27, No. 12, 1010-1015 (1961). T h e factors w h i c h govern dip-soldering" of p r i n t e d circuits are discussed. E x p e r i m e n t a l data o f d i p p i n g time against t e m p e r a t u r e and m e a s u r e m e n t s of the t e m p e r a t u r e rise with time, are described.
RELIABILITY OF COMPONENTS,
TUBES AND TRANSISTORS
E f f e c t s o f t e m p e r a t u r e o n h i g h - f r e q u e n c y t r a n s i s t o r s . C. R. Grc~v and T . C. SOWERS, Electro-Technology, July 1962. Variations in the parameters, power gain, b a n d w i d t h , noise figure, p o w e r o u t p u t and f r e q u e n c y shift are caused by t e m p e r a t u r e changes in the h i g h - f r e q u e n c y g e r m a n i u m diffused-base transistor. A n u m b e r of m e a s u r e m e n t s have been m a d e w h i c h relate h i g h - f r e q u e n c y transistor p a r a m e t e r s to a m b i e n t t e m p e r a t u r e ranges f r o m - - 6 0 ° to 80~C. M e a s u r e m e n t o f s e m i c o n d u c t o r c o m p o n e n t p a r t s i n m a n u f a c t u r e . (In G e r m a n . ) G. F.~BE.XDER, Nachrichtentechnik 13, No. 1, p. 16 (1963). A m a n u f a c t u r e of desired types of s e m i c o n d u c t o r c o m p o n e n t parts is still impossible today. Therefore, the different types m u s t be obtained o u t of a whole m a n u f a c t u r e d series by m e a s u r e m e n t . T h i s requires special h i g h - s p e e d m e a s u r i n g i n s t r u m e n t s , w h o s e function is described in the article. D e s i g n a n d c o n s t r u c t i o n o f a n a u t o m a t i c t r a n s i s t o r t e s t i n g a n d s o r t i n g m a c h i n e . (In G e r m a n . ) H. TILCX~R, .Vachrichtentechnik 13, "No. 1, p. 23 (1963). A n a u t o m a t i c m a c h i n e is described w h i c h is designed to test L . F . transistors of low power. T h e m a c h i n e possesses a capacity of 1000 pieces;hr and classes according to types and causes of rejection. T h e highest possible n u m b e r of yes-no m e a s u r e m e n t s is 28 with 36 types including rejects. T h e e l e c t r i c a l p r o t e c t i o n o f s e m i c o n d u c t o r d e v i c e s i n t h e l i g h t o f a v a i l a b l e d a t a . G. D. PER~qI>'S, Brit. Communicat. Electron., July 1962. A short rdsum6 of the different kinds of faults w h i c h o c c u r and the necessary data to enable the circuit protection engineer to make his own calculations a n d choose appropriate protective devices. c o m p o n e n t a n a l y s i s u t i l i z i n g s h o r t - t e r m m a t e r i a l s a n d d e s i g n s t u d i e s . \V. E. DCNKV-L, Proc. Sth National Syrup. on Reliability and Quality Control, W a s h i n g t o n , D.C., Jan. 1962, pp. 520-523. Describes h o w
Long-term
tests of short duration can be used to predict the life of electronic c o m p o n e n t s u s i n g accelerated life tests. * Based on Electrical Engineering Abstracts by kind permigsion of T h e I n s t i t u t i o n of Electrical Engineers.