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Testing ICs at high temperatures
World Abstracts on Microelectronics and Reliability investigated. It has been assumed that a failure in L~ brings about the complete break-down of the system whereas a failure of two components in class L 2 causes the system to work in a state of reduced efficiency. The repair of the failed components in class L 1 and L 2 is carried out under the Preemptive Resume Repair Discipline. Laplace Transforms of various state probabilities, viz. the system is in up state, reduced efficiency state and down state, have been obtained. In the end, asymptotic behaviour of the complex system, has also been examined.
ProbabUistic analysis of a 2-unit cold-standby system with a single repair facility. S. K. SRINIVASANand M. N. GOPALAN. IEEE Trans. Reliab. R-22, 250 (Ded. 1973). The reliability and the availability characteristics of a 2-unit cold standby system with a single repair facility are analyzed under the assumption that the failure and the repair times are both generally distributed. System breakdown occurs when the operating unit fails while the other unit is undergoing repair. The system is characterized by the probability of being up or down. Integral equations corresponding to different initial conditions are set up by identifying suitable regenerative stochastic processes. The probability of the first passage to the down-state starting from specified initial conditions is obtained by the same method. An explicit expression for a Laplace Transform of the probability density function (pdf) of the downtime during an arbitrary time interval is obtained when the repair time is exponentially distributed. A general method is suggested for the calculation of the m o m e n t s of the downtime when the repair time is arbitrarily distributed. A method of redundancy allocation. K. B. MISRA. Microelectron. & Reliab. 12, 389 (1973). A simple and new method is provided for allocating redundancies to various stages of a system, to maximize the system reliability under some given c o n s t r a i n t s The approach suggested does not require tedious and long computations. The approach may be helpful to system designers to arrive at the solution quickly with little algebraic manipulation. The feasibility of developing standard redundancy allocation charts in the case of simple forms of the constraints is indicated. A fast method for redundancy allocation. K. B. MISRA. Microelectron. & Reliab. 12, 385 (1973). A fast method for redundanc) allocation for a series system is described in this paper. The approach makes use of some of the special
77
features of the problem and thereby reduces it to the solution of a set of inequalities. Two illustrative problems-- one with linear and the other with the non-linear constraints are given as examples. The type of constraints and the number of stages do not set a limitation on the choice of this approach as with the existing methods. Reliability of a Quasi-Redundant electronic system with "Standby" in the main unit. S. SAWHNEY. Microelectron & Reliab. 12, 289 (1973). The reliability of a quasi-redundant electronic system with a standby in the main Unit has been studied. It is assumed that failure and repair time distribution of each unit is negative exponential with parameters 2 and ]t respectively. Laplace transforms have been used in solving the difference-differential equations. Stand-by redundancy complex system's reliability. R. C. GARG and C. M. SHARMA. Microelectron. & Reliab. 12, 321 (1973). In this paper the behaviour of a complex system having two classes of components has been investigated. The configuration of the system is such that in one class the components are connected in series and in the other class in stand-by redundancy. Further, it has been assumed that repair of the failed components of both the classes is carried under the head of line repair discipline. The Laplace transforms of various state probabilities have been obtained. Asymptotic behaviour of such a system has also been examined. In the end a particular case has been derived. Distribution of time to non-availability of a reliability system. N. SINGH. Microelectron. & Reliab. 12, 337 (1973). The author derives in this paper the distribution of thc time to non-availability of a system which under-goes thc following states, viz. (i) operative (ii) failed, and (iii) repair. Special cases are discussed and tables are provided at the end. Analytic study of a stand-by redundant equipment with switching and shelf life failures. S. PRAKASH. Microelectron. & Reliab. 12, 329 (1973). An analytic study of a stand-by redundant equipment consisting of two components with imperfect switching-over device, has been carried out under the assumption that the stand-by component ma~ fail during its shelf life. Time dependent probabilities of various states of the equipment have been obtained. The bchaviour of the equipment under steady state has also been examined.
4. M I C R O E L E C T R O N I C S - - G E N E R A L Custom LSI fades into background. O. SIDERIS. Electronics system-control and random-logic functions will be served in 74 (10 Jan. 1974). While M O S houses willing to accept the last half of the decade by LSI microprocessors or contracts for 5000 or 10,000 custom arrays a year are few and programed logic arrays, according to some companies. far between, that doesn't mean the average equipment manufacturer will be LSl-poor in the future. As the swing Testing ICs at high temperatures. Electronics, 134 17 Feb. accelerates toward standard products, there is general 1974). Production-type handler permits rapid checkout of agreement that the need for custom memory and logic is M O S RAMs and other circuits in DIPs to spot failure modes easing up. And most of the requirements for specialized in high-density applications. 5. M I C R O E L E C T R O N I C S
DESIGN
Digital-IC models for computer-aided design. Part 2: TTL flip-flops. J. R. GREENBAUM and W. A. MILLER. Electronics 107 (20 Dec. 1973). Flip-flops are medium-scale integrated circuits that can be modeled very simply, just like N A N D gates [Electronics, Dec. 6, p. 121], by developing a black-box
MR--Vol. 13. No. 2--B
AND CONSTRUCTION
equivalent circuit. The model given here for a D-type flip-flop is based on the T T L 9774 dual flip-flop, and the model for a J-K master slave device is based on another TTL unit, the radiation-hardened RSN54L72 flip-flop.
ProbabUistic analysis of a 2-unit cold-standby system with a single repair facility. S. K. SRINIVASANand M. N. GOPALAN. IEEE Trans. Reliab. R-22, 250 (Ded. 1973). The reliability and the availability characteristics of a 2-unit cold standby system with a single repair facility are analyzed under the assumption that the failure and the repair times are both generally distributed. System breakdown occurs when the operating unit fails while the other unit is undergoing repair. The system is characterized by the probability of being up or down. Integral equations corresponding to different initial conditions are set up by identifying suitable regenerative stochastic processes. The probability of the first passage to the down-state starting from specified initial conditions is obtained by the same method. An explicit expression for a Laplace Transform of the probability density function (pdf) of the downtime during an arbitrary time interval is obtained when the repair time is exponentially distributed. A general method is suggested for the calculation of the m o m e n t s of the downtime when the repair time is arbitrarily distributed. A method of redundancy allocation. K. B. MISRA. Microelectron. & Reliab. 12, 389 (1973). A simple and new method is provided for allocating redundancies to various stages of a system, to maximize the system reliability under some given c o n s t r a i n t s The approach suggested does not require tedious and long computations. The approach may be helpful to system designers to arrive at the solution quickly with little algebraic manipulation. The feasibility of developing standard redundancy allocation charts in the case of simple forms of the constraints is indicated. A fast method for redundancy allocation. K. B. MISRA. Microelectron. & Reliab. 12, 385 (1973). A fast method for redundanc) allocation for a series system is described in this paper. The approach makes use of some of the special
77
features of the problem and thereby reduces it to the solution of a set of inequalities. Two illustrative problems-- one with linear and the other with the non-linear constraints are given as examples. The type of constraints and the number of stages do not set a limitation on the choice of this approach as with the existing methods. Reliability of a Quasi-Redundant electronic system with "Standby" in the main unit. S. SAWHNEY. Microelectron & Reliab. 12, 289 (1973). The reliability of a quasi-redundant electronic system with a standby in the main Unit has been studied. It is assumed that failure and repair time distribution of each unit is negative exponential with parameters 2 and ]t respectively. Laplace transforms have been used in solving the difference-differential equations. Stand-by redundancy complex system's reliability. R. C. GARG and C. M. SHARMA. Microelectron. & Reliab. 12, 321 (1973). In this paper the behaviour of a complex system having two classes of components has been investigated. The configuration of the system is such that in one class the components are connected in series and in the other class in stand-by redundancy. Further, it has been assumed that repair of the failed components of both the classes is carried under the head of line repair discipline. The Laplace transforms of various state probabilities have been obtained. Asymptotic behaviour of such a system has also been examined. In the end a particular case has been derived. Distribution of time to non-availability of a reliability system. N. SINGH. Microelectron. & Reliab. 12, 337 (1973). The author derives in this paper the distribution of thc time to non-availability of a system which under-goes thc following states, viz. (i) operative (ii) failed, and (iii) repair. Special cases are discussed and tables are provided at the end. Analytic study of a stand-by redundant equipment with switching and shelf life failures. S. PRAKASH. Microelectron. & Reliab. 12, 329 (1973). An analytic study of a stand-by redundant equipment consisting of two components with imperfect switching-over device, has been carried out under the assumption that the stand-by component ma~ fail during its shelf life. Time dependent probabilities of various states of the equipment have been obtained. The bchaviour of the equipment under steady state has also been examined.
4. M I C R O E L E C T R O N I C S - - G E N E R A L Custom LSI fades into background. O. SIDERIS. Electronics system-control and random-logic functions will be served in 74 (10 Jan. 1974). While M O S houses willing to accept the last half of the decade by LSI microprocessors or contracts for 5000 or 10,000 custom arrays a year are few and programed logic arrays, according to some companies. far between, that doesn't mean the average equipment manufacturer will be LSl-poor in the future. As the swing Testing ICs at high temperatures. Electronics, 134 17 Feb. accelerates toward standard products, there is general 1974). Production-type handler permits rapid checkout of agreement that the need for custom memory and logic is M O S RAMs and other circuits in DIPs to spot failure modes easing up. And most of the requirements for specialized in high-density applications. 5. M I C R O E L E C T R O N I C S
DESIGN
Digital-IC models for computer-aided design. Part 2: TTL flip-flops. J. R. GREENBAUM and W. A. MILLER. Electronics 107 (20 Dec. 1973). Flip-flops are medium-scale integrated circuits that can be modeled very simply, just like N A N D gates [Electronics, Dec. 6, p. 121], by developing a black-box
MR--Vol. 13. No. 2--B
AND CONSTRUCTION
equivalent circuit. The model given here for a D-type flip-flop is based on the T T L 9774 dual flip-flop, and the model for a J-K master slave device is based on another TTL unit, the radiation-hardened RSN54L72 flip-flop.