Lead Temperature due to Soldering?

[ohmrun]

The absolute maximum ratings for an integrated circuit states that the lead temperature should not exceed 260 C. And in parenthesis it states "Soldering, 10 seconds". Does this mean that the lead can be at 260 C for 10 seconds? Does it imply that it can be soldered with a higher temperature tip for a shorter time and if so, is there a rule of thumb for that time/temperature combination?
Thanks

 

[radomir]

Unfortuntely there is no rule of thumb because each alloy has its own thermal conductivity ("heating inertia&quot and wire gauge play also a rolle in temperature raise ratio. Definitely those wires can stand 260 deg C indefinitely (theoretically unlimited period of time). I suppose that soldering temperature is higher, therefore probably those gentlemen and gentle-womem (manufacturers) have tested the whole thing and have specified a safe time period (which is probably half of the possible one). Just my wild guess but who knows maybe I am right.

You may also try to cool adjacent portion of the integrated circuit (I suppose bord) while soldering but somehow not cooling the soldering location (use of some heat sink). That will give you at least those 20 seconds to carry out the soldering. Or solder intermittently if possible.

 

[IRstuff]

At this point in time, there should be no reason to take more than about 3-5 seconds per joint. If not, it may be time to get a new solderer ;-), either that, or you are not using the right kind of solder/flux. The main key is proper preparation of the joint components with cleaning/fluxing.

While some of the materials can withstand 260C indefinitely, not all the materials can do that, particularly, plastic packaging, some organic overcoats, etc.

Moreover, even 260C is suffciently high enough to potentially cause/accelerate junction spiking on inputs and outputs.

 

[ohmrun]

The reason for asking the question is that if I use a soldering iron with a 700 F or 800 F (370 C or 425 C) tip, for about 2 seconds, what happens? Will I exceed the equivalent of 260 C for 10 seconds?

 

[dvd]

why don't you ask the manufacturer exactly what they mean?

 

[saxon]

mryan, What this standard is imposing is a maximum allowable temp. and time that the lead and hence the electronic component can see. Otherwise the compnent will in all probablity fry. If you can't maintain this std., try a removable lead heat sink between the joint and the components. be particuliarly careful with transistors and diodes.

saxon.