Next stop on the avenue of package thermal modelling is 2 resistor CTMs (compact thermal models). Specifically Theta_jb and Theta_jc, the thermal resistance between junction and board and junction and case respectively. Unlike their lowly 1R cousins these two resistances do not purport to include the effects of the package environment (well almost not) as such they should in … [Read more...]

Just a quick post to let you know yours truly will be giving a presentation on: Thermal Design: A Key Part of the Electronics Design Flow At the UK Solutions Expo at the Heritage Motor Centre in Gaydon on 12th November. Miniaturization continues to increase power densities at all packaging levels, forcing design teams to identify new methods of cooling. The challenge remains … [Read more...]

The simplest of compact thermal models (CTMs) is a one resistor type. Of these the most widely quoted is Theta_ja (ok, ok, and Theta_jma, more on that variant later). Knowing the power dissipation of the component as well as the ambient temperature is in theory all that is required to determine the junction temperature from the supplied Theta_ja resistance value. You would … [Read more...]

I read in the news this last week that Sir Tim Berners-Lee, a Brit and the inventor of the World Wide Web, has confessed that the // in a web address were actually “unnecessary”… and it seems that polar ice will be gone in the summer, perhaps by as early as 2020, opening the arctic ocean to shipping. At the same time I’m writing this on my laptop, the fan’s just … [Read more...]

Lumped block package representation makes the best use of limited available data to simulate for an ‘indication’ of case temperature. Some indication is better than none but I wouldn’t bet on it, really, I wouldn’t. Accurate case and junction temperature prediction can only be realised with either a fully 3D detailed representation or an abstracted CTM … [Read more...]