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TPS7H1101A-SP: Soldering Process(ROHS or NON-ROHS) and placement of component during automatic soldering

LALIT VERMA
Expert 1645 points
Part Number: TPS7H1101A-SP

Hello,

We are using engineering model (TPS7H1101HKR/EM) of TPS7H1101A-SP SPACE GRADE LDO and will be going for assembly in one or two weeks.

The package of TPS7H1101HKR/EM is ceramic dual flat pack. The pins and bottom themal pad are not aligned and in order to make contact between pins and PCB, the pins need to be bend otherwise ,thermal pad in the bottom of IC will make contact with PCB and pins will be floating during reflow process.

Along with TPS7H1101HKR/EM, we are also using engineering model of SPACE GRADE components given below

Part Number

Description 

LMX2615W-MPR

Clock Synthesizer

TMP461HKU/EM

Temperature Sensor

TPS50601HKH/EM

DC-DC  Switching Regulator

TPS7H3301HKR/EM

DDR Termination Regulator

and all this components have ceramic flat pack same as that of TPS7H1101HKR/EM.

I have seen a video from Fancort Industries, and they are bending the pins using some machines.

Here is the link https://youtu.be/hwblw74KTUA .

So, I have following questions :

  1.       Is there any method of bending pins manually without using machines so that they can make contact with board during assembly process?
  2.       Which soldering process to be used- ROHS or NON-ROHS?

Infact will you guys,please fill the below parameters related to soldering process as I am not able to find these in datasheets:

Parameters

TI's Response

Soldering Process(ROHS or NON-ROHS)

 

MSL Level

 

Baking Time

 

Baking Temperature

 

Peak Soldering Temperature

 

Minimum Preheat Temperature and time

 

Maximum Preheat Temperature and time

 

Ramp-Up Time

 

Ramp-Down Time

 

 

It will be better if you guys can share SOLDERING PROFILE GRAPH indicating all these parameters.

And I am guessing same soldering profile can be used with all the components listed above. Am I right about that?

An early response will be highly appreciated as we are planning for assembly in one or two weeks.

 

Thanks & Regards,

Lalit

  • 0
    TI__Mastermind 25235 points

    Hey Lalit,

    We are trying to find as much data as we can for you.

    In the mean time please know that the devices will need to be trimmed and formed somehow.

    We have a recommendation available, but how they get trimmed and formed is up to the customer (likely by machine).

    16HKR.pdf

    Thanks,

    Daniel

  • 0 in reply to Daniel Hartung
    Expert 1645 points

    Hi Daniel,

    Thanks for the quick reply.

    Along with the information related to soldering processes like MSL, peak soldering temp. etc, I also have a another query.

    In TPS7H1101A-SP, it is mentioned that the pins of IC are gold plated. So ,do I need to get the pins of IC solder dipped or tinned prior to mounting the IC on PCB.

    Thanks,

    Lalit

  • 0 in reply to LALIT VERMA
    TI__Mastermind 25235 points
    Hey Lalit,

    This is our standard reply for all soldering profile questions:

    • At the board level, solder reflow profiles are dependent on numerous factors including, but not limited to, solder type, flux, package type, number of components, board layers, board size, reflow oven type and accuracy as well as pre and post cleaning processes. Because of the number of variables it is not possible to provide a single reflow profile that is representative of every board using a specific package type. Typically manufacturing houses have reflow profiles in place and modify them for specific hardware.

    • TI suggests using the flux manufacturer’s recommended profile as a starting point. In general ceramic parts are compatible with ramp-rates of less than or equal to 5°C/second with a maximum temperature of 265°C. Variations of course need to be comprehended based on time required to volatize the flux prior to the solder reaching liquidus.

    • Metal lid packages use a 80%Au20%Sn gold-tin solder preform to attach the lid. Gold-tin solder will begin to soften at 270°C and has a eutectic point of 280°C. The package body temperature must not be allowed to exceed 265°C at any time or permanent damage will occur due to compromising the package’s hermetic seal. Note that though-hole hermetic device specify a maximum temperature for soldering as a lead-temperature of 300°C for 10 seconds. This is not a reflow temperature.

    • When using gold-plated leads or pads with MIL-SPEC plating thickness (60 µ-in to 225 µ-in), it is strongly recommended that the units be pre-tinned (solder-dipped) before board mounting to scavenge the gold from the leads or pads. If this is not done there is a chance of gold-embrittlement of the board-level solder-joints. A flowing solder-pot or two passes in a static solder-part is recommended.

    Hopefully this clears up some of your questions.

    Thanks,
    Daniel
  • 0 in reply to Daniel Hartung
    Expert 1645 points

    Hi Daniel,

    Thanks for the useful information.

    In datasheet of TPS7H1101HKR/EM, page 29, in Package information table MSL level for TPS7H1101HKR/EM is written as N/A.

    Is this because of ceramic packaging, which is not sensitive to moisture?

    • And does it mean, we don't need to bake the TPS7H1101HKR/EM before soldering the TPS7H1101HKR/EM on PCB?

    Also for LMX2615(Clock synthesizer), under Package information Table in datasheet, MSL level is not mentioned and requested to "Call TI" for MSL level.

    • So, does LMX2615 requires baking prior to soldering on PCB and if so please provide the MSL level for LMX2615 and also baking temperature and baking time.

     

    Also one more thing, we are planning to go with NON-ROHS soldering profile with peak temperature in between of 220 oC and 225 oC, as there are some other components on our board which are not ROHS compatible. Is it ok with TPS7H1101HKR/EM and other TIs components we are using in our project as mentioned earlier?

     

    Thanks,

    Lalit

  • 0 in reply to LALIT VERMA
    TI__Mastermind 25235 points
    Hey Lalit,

    Ceramic packages are not sensitive to moisture and thus do not need to be baked ahead of time.

    I need some time to see what we say about the peak temperature.

    Thanks,
    Daniel
  • 0 in reply to Daniel Hartung
    TI__Mastermind 25235 points

    Hey Lalit,

    On the peak temperature thing I guide you to read part two of what I said:

    TI suggests using the flux manufacturer’s recommended profile as a starting point. In general ceramic parts are compatible with ramp-rates of less than or equal to 5°C/second with a maximum temperature of 265°C. Variations of course need to be comprehended based on time required to volatize the flux prior to the solder reaching liquidus.

    Thanks,

    Daniel

  • 0 in reply to Daniel Hartung
    Expert 1645 points

    Hi Daniel,

    Thanks for this information.

    I have some more questions for you.

    Does TI has some recommendations of solder-paste for NON-ROHS profile and also cleaning of PCBs after reflow?

    Which solder paste , would be better to used with TI components mentioned in the question, like Rosin flux based, water soluble flux based or no clean flux based?

    Also which cleaning process should be used after reflow , like  Isopropylic Alcohol based or de-ionized water based or any other cleaning process TI recommends?

    Kind Regards,

    Lalit

  • 0 in reply to LALIT VERMA
    TI__Mastermind 25235 points

    Hey Lalit,

    This more refers to the first part of the response:

    • At the board level, solder reflow profiles are dependent on numerous factors including, but not limited to, solder type, flux, package type, number of components, board layers, board size, reflow oven type and accuracy as well as pre and post cleaning processes. Because of the number of variables it is not possible to provide a single reflow profile that is representative of every board using a specific package type. Typically manufacturing houses have reflow profiles in place and modify them for specific hardware.

    Pretty much there are too many variables for us to analyze to give a guaranteed answer.

    Does the manufacturing house you have not have a profile for this type of device in place?

    Thanks,

    Daniel 

  • 0 in reply to Daniel Hartung
    TI__Mastermind 25235 points
    Hey Lalit,

    Has this been resolved?