Reflow damaging opto FET
T Chap
Posts: 4,223
http://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=H11F1SM-ND&x=28&y=20
On more than a few occasions this part has been damaged in the oven. It is the only part out of hundreds of boards over the years that I have experienced damage with. I cannot say for sure that the temperature rate of change up or down is being adhered to, but in terms of max temp and duration, I am not exceeding any limits on the datasheet.
Here is the issue that appears in maybe 1 out of 5 boards from the oven on this part:
On the transistor side of the IC, it has two non specific "output terminals" such that AC or DC can flow in any direction. The part is being used in a voltage divider circuit, driven by PWM off the Prop. Pin 6 has 6.5VDC. When the part is working fine, Pin 4 which is one of the terminals will normally have 1.6VDC on it under a certain test. When the part is damaged, it may be around 1VDC. This weekend I experienced the part getting damaged again, and replaced the part with new one with a hot air rework station, it did not get excessively hot in my opinion, but still damaged another new part again installing it with hot air. This time the voltage was 1.3VDC under the test. So, I finally used a pencil on a third new IC and the pin 4 was back to normal at 1.6VDC under the exact same test.
I can easily solve this problem by soldering it with a pencil for future production, but it is really puzzling me how the heat is affecting the part in this very consistent way. Anyone have an experience with this behavior?
On more than a few occasions this part has been damaged in the oven. It is the only part out of hundreds of boards over the years that I have experienced damage with. I cannot say for sure that the temperature rate of change up or down is being adhered to, but in terms of max temp and duration, I am not exceeding any limits on the datasheet.
Here is the issue that appears in maybe 1 out of 5 boards from the oven on this part:
On the transistor side of the IC, it has two non specific "output terminals" such that AC or DC can flow in any direction. The part is being used in a voltage divider circuit, driven by PWM off the Prop. Pin 6 has 6.5VDC. When the part is working fine, Pin 4 which is one of the terminals will normally have 1.6VDC on it under a certain test. When the part is damaged, it may be around 1VDC. This weekend I experienced the part getting damaged again, and replaced the part with new one with a hot air rework station, it did not get excessively hot in my opinion, but still damaged another new part again installing it with hot air. This time the voltage was 1.3VDC under the test. So, I finally used a pencil on a third new IC and the pin 4 was back to normal at 1.6VDC under the exact same test.
I can easily solve this problem by soldering it with a pencil for future production, but it is really puzzling me how the heat is affecting the part in this very consistent way. Anyone have an experience with this behavior?
Comments
how long you can solider at what temp all other data sheet tell you this Info on this part #
I post the data sheet that was written in 2002 for you
before 2002
The part # H11F1W
After 2003 This data sheet was written in 2003
The part # H11F1M
I have to wonder if they are making these chips different some how