you may have restrictions on your reflow profile.  The different color of
LED normally have different requirement in terms of thermal extreme (due to
the material used for LED die).  If you got all color, your profile is going
to be tricky (if you have other devices on board, such as controller,
normally in format of qfp).  you may have to get the SMT regular stuff
reflowed 1st, and put on the LED next using specific profile (your manager
wouldn't happy to hear that... cycle time extension).  Here is one of the
required profile for all color LED for your reference only.  Good luck.
http://www.fairchildsemi.com/ds/QT/QTLP650D-RGB.pdf
my 1.57 cent (hehehe, I am close to 2 cents now)...
                                       jk

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Prasad AN
Sent: Wednesday, September 29, 2004 10:42 PM
To: [log in to unmask]
Subject: Re: [TN] Reliability issue in 0402 soldering


Hi JK

The colors are around 470 of RED, 100- Green and remaining is Blue

Thanks with Warm regards

A.N.Prasad


-----Original Message-----
From: Joyce Koo [mailto:[log in to unmask]]
Sent: Wednesday, September 29, 2004 6:50 PM
To: TechNet E-Mail Forum; Prasad AN
Subject: RE: [TN] Reliability issue in 0402 soldering

what is the color of your LED?
             jk

-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Prasad AN
Sent: Wednesday, September 29, 2004 4:14 AM
To: [log in to unmask]
Subject: [TN] Reliability issue in 0402 soldering


Hi all

We are assembling around 750 # of 0402 size LEDs in small PCB of size 65mm X
65mm.

The problem we are having after reflow, when PCB is tested all the LEDs are
glowing.

But after some time the problem starts with 3-4 LEDs not glowing.

The PCB surface is of  Tin plating.

Let me know is the PCB surface is suitable for this type of board. If not
what type of surface is recommended for PCB with only 0402 LEDs.


Thanks with Warm regards

A.N.Prasad




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