Hi,
Thanks everyone. Can you also help me to answer the queries related to the component spacing?
Rgds
Prashant
--- On Wed, 21/10/09, Stadem, Richard D. <[log in to unmask]> wrote:
From: Stadem, Richard D. <[log in to unmask]>
Subject: Re: [TN] PWB Layout spacing queries
To: [log in to unmask]
Date: Wednesday, 21 October, 2009, 8:51 PM
Reuven
I could not agree with you more. Systems such as the Hakko IR pre-heater station and the Hakko Hot Air system are the perfect solution.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Reuven Rokah
Sent: Wednesday, October 21, 2009 9:10 AM
To: [log in to unmask]
Subject: Re: [TN] PWB Layout spacing queries
Hi Prashant,
Controlled IR soldering tool (with thermocouple and bottom PCB pre heating) is the best for such small BTC / QFNs components (without air pressure).
Best Regards
Reuven ROKAH
Think green before printing this mail... Thanks
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of prashant chopra
Sent: Wednesday, October 21, 2009 2:43 PM
To: [log in to unmask]
Subject: [TN] PWB Layout spacing queries
Hi,
I have a couple of queries with regard to the component spacing ---
1. What should be the minimum spacing between the QFP and the nearest chip components? (Assuming that the in case of failures the QFP will be reworked manually using the soldering iron).
2. What should be the minimum spacing between the QFN package and the nearest chip component? ( I am attaching a datasheet of QFN above).
3. What should be the minimum spacing between the 0402 component and the other nearest 0402 component or chip component?
Also, I have one query reagrding the QFN rework process (datasheet attached above) --
1. Ideally, in case of replacing the old QFN, the rework procedure should be similar to the BGA rework procees and using the rework station and nozzle. But, one of our manufactuirng location is not having the rework station. They rework it manually, using the hot air gun to remove the component. Then they place the new QFN component and solder the small portion visible on the side edges (as shown in side view in data sheet) using the soldering iron. But I believe, this will not allow much solder to flow below the part and form contact there as major portion of the pad is below the body of the QFN. Is this process reliable? Will it have any impact on the performance over a period of time? is there any other reliable manual process which can be used for this rework?
Appreciate all your help and response. Thanks in advance.
Rgds
Prashant
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