PRINTED WIRING ASSEMBLIES : RELIABILITY STRESS SCREENING
Page 1 Scope . . . . . . . . . . . . . . . . . . . . . . . . 2 2 Field of application . . . . . . . . . . . . . . . . . . . 2 3 Reference . . . . . . . . . . . . . . . . . . . . . . . 2 4 Definitions . . . . . . . . . . . . . . . . . . . . . . . . 2 5 Sampling . . . . . . . . . . . . . . . . . . . . . . . 3 5.1 Sample preparation . . . . . . . . . . . . . . . . . 3 5.2 RSS time planning . . . . . . . . . . . . . . . . . 4 5.3 Reduced RSS process determination . . . . . . . 4 6 Method of RSS . . . . . . . . . . . . . . . . . . . . 4 6.1 Principle . . . . . . . . . . . . . . . . . . . . . . . 4 6.1.1 Initial RSS test . . . . . . . . . . . . . . . . . 4 6.1.2 Optimum RSS process duration . . . . . . . 4 6.1.3 Function test . . . . . . . . . . . . . . . . . . 4 6.1.4 Pass/failure criteria . . . . . . . . . . . . . . 4 6.1.5 Failure analysis . . . . . . . . . . . . . . . . 5 6.1.6 Selection of stress types and stress levels . . . 5 6.2 Applicable stress types . . . . . . . . . . . . . . . 5 6.2.1 Constant high temperature . . . . . . . . . . 5 6.2.1.1 Passive “bake” process . . . . . . . . 5 6.2.1.2 “Bake” process with applied voltage . . . 6 6.2.1.3 “Bake” process with power dissipation . . 6 6.2.2 Low/high temperature cycling . . . . . . . . . 6 6.2.2.1 Passive temperature cycling . . . . . 6 6.2.2.2 Temperature cycling with power dissipation . . . . . . . . . . . . . . . . 6 6.2.3 Vibration and other mechanical stress . . . . 7 6.2.3.1 Fixed frequency sinusoidal vibration . . . 7 6.2.3.2 Swept frequency sinusoidal vibration . . 8 6.2.3.3 Random vibration . . . . . . . . . . . 8 6.2.3.4 Bump . . . . . . . . . . . . . . . . . 8 6.2.3.5 Other mechanical stresses . . . . . . 8 6.2.4 Combination of temperature cycling and random vibration . . . . . . . . . . . . . . . . . . . . 8 6.2.5 Humidity . . . . . . . . . . . . . . . . . . . . 9 6.2.5.1 Constant high humidity and temperature . . . . . . 9 6.2.5.2 High humidity and temperature cycling . . . . . . 9 6.2.6 Operational stress . . . . . . . . . . . . . . . 9 6.2.6.1 Constant operational stress . . . . . . 9 UDC 621.38
Reliability of plastic-encapsulated logic circuits
Families of plastic-encapsulated logic circuits have been subjected to a qualification procedure. The aim was to qualify them for use in telecommunication equipment in a central office environment. The qualification was based on a large number of reliability tests performed by the Ericsson failure analysis laboratory and by the vendors themselves. Reliability monitoring data from the testing of more than 150,000 devices during the period 1984 to 1985 have been analysed. Life tests, such as ‘high temperature operating life’, ‘high humidity operating life’, and temperature cycling have been performed. A comparison between life-test data and field data from telephone exchanges in service has also been made. An average activation energy of 0.5 eV has been shown to be useful in such a comparison for the best LS vendors and 0.3 eV for the best HCMOS vendors.
State estimation for integrated vehicle dynamics control
This paper discusses a vehicle controller and a state estimator that was implemented and tested in a vehicle equipped with a combined braking and chassis control system to improve handling. The vehicle dynamics controller consists of a feed forward body roll compensation and a feedback stability controller. The estimator is based on a non-linear vehicle model combined with an extended Kalman filter. The Kalman filter is also connected to an algorithm, which estimates the tyre-road friction coefficient. The developed estimator was tested in a vehicle. Good results were achieved for normal and extreme driving manoeuvers.