LM317A: Mounting of TO-220

Atsushi Takahashi

Expert 1415 points

Part Number: LM317A

Tool/software:

Hi Team,

I'd like some advice on mounting this product.

Generally, I think it would be mounted at side A(See attached) to the PCB's through-hole.

However, the through-hole on the customer's PCB is large, so they are thinking of mounting it at side B.

In this way, the mold and PCB will be in close contact.

Is this mounting method a problem?

Best Regard,

11 months ago

0 Srikanth Lolla Venkata 11 months ago

TI__Genius 12960 points

Hi Atsushi,

I do not see any concern with the leads sent all the way down. Thanks!

Regards,

Srikanth

0 Atsushi Takahashi 11 months ago in reply to Srikanth Lolla Venkata

Expert 1415 points

Hi Srikanth-san,

Thank you for your reply.

I have two additional questions.

1) Are the mounting conditions (time, temperature, etc.) the same whether mounting with side A or side B?

2) Is hand soldering recommended for this device? If yes, please tell me the conditions (time, temperature, etc.).

0 Srikanth Lolla Venkata 11 months ago in reply to Atsushi Takahashi

TI__Genius 12960 points

Hello Takahashi-San,

I apologize for the delay in getting back to you, I was out of office last week. I cannot think of a reason why the mounting conditions should be different. Texas Instruments offers some recommendations for wave and reflow soldering and they are detailed in the following two app notes:

(1 ) App Note 1.

(2) App Not 2

Thanks!

Regards,

Srikanth

0 Atsushi Takahashi 11 months ago in reply to Srikanth Lolla Venkata

Expert 1415 points

Hi Srikanth-san,

Thank you for your reply.

I checked the application note you sent, however, it doesn't mention hand soldering. Does it mean that TI doesn't recommended hand soldering?

0 Srikanth Lolla Venkata 11 months ago in reply to Atsushi Takahashi

TI__Genius 12960 points

Hi Atsushi-San,

Please give me 1 business day, I will confirm with our packaging team if there are any recommendations for hand soldering.

Regards,

Srikanth

0 Srikanth Lolla Venkata 11 months ago in reply to Srikanth Lolla Venkata

TI__Genius 12960 points

Hi Atsushi-San,

Our packaging team does not recommend hand soldering for the TO-220 package, since it is very difficult to control the temperature. If it must be hand soldered, please use X-ray to inspect the fill % post soldering. Thanks!

Regards,

Srikanth

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LM317A: Mounting of TO-220