SE555-SP: RGA failure and anomaly

Hi Yohei,

What is the dielectric type and voltage for capacitor C31?  Also, you mentioned "external condensers", is this represented in the schematic as one of the components?  Can you obtain a waveform at the "THRESH" and "OUT" pins?

Regarding specifically topic #1 and #2 (sealed under atmospheric pressure/date code), this information is not typically supported on the e2e forum.  We support product functionality questions, but issues related to packaging/assembly/lot information must be directed through the local field support/sales team.  Please contact the local sales office to address these questions.  

We will do what we can to support the debug from the electrical performance, though.  Please let me know the answers to the first questions and let's see if we can figure it out from there.

Regards,
Mike

Hi Mike,

Thank you so much for your kind reply.

Please allow me to check with a customer regarding dielectric type and voltage for capacitor C31.

I'll also check regarding the external condensers as well and come back you as soon as advised.

For questions #1 and 2, I did ask to TI support and they advise me to post the questions here on E2E...

It'll be grateful if you could kindly provide us where I should go for questions #1 and 2.

Thank you again for your kind support.

Kind Regards,

Yohei

Hi Yohei,

We will have to investigate further where to get the requested information, I will get back to you by the end of this week.

Regards,
Mike

Hi Mike,

Thank you so much for your kind reply and warm consideration.

Yes, it'll be great if you could kindly find out and advise where to go for question 1 and 2...

I have asked our Japan team for your request and will be get back to you in ASAP as I am advised.

Thank you again!

Kind Regards,

Yohei

Hi Mike,

Hope you're well.

Please allow me to attach the files from customer and comments...

Frequency with part names.pdf

 1) C31 Condenser.

     Rated Voltage=50V

     Please kindly refer to the attached PDF for part names.

2) External Resister and Condenser

     We used 1pc each. Please kindly refer to the attached PDF for circuit design. 

 3) Wave forms for THRESH(Pin6) and OUT(Pin3)

     Please kindly refer the attached files.

The one we assembled for EM which mentioned previously, we used P/N : JM38510/10901BPA and peripheral circuit was the same for this time.

Also, we used condenser used in EM to FM just in case but unfortunately we couldn't solve its malfunction.

We used same type/lot resister for both EM and FM.

Hope it helps...

Thank you for your kind support.

Kind Regards,

Yohei

Hi Yohei,

The manufacturer has a specification of +/10% on the timing capacitor that is used in the circuit. This combined with the resistor tolerances of 1% per resistor and the variation of threshold and trigger values can explain a lot of the variation that is being seen with the expected frequency value not matching the measured value. We recommend to use high quality COG/NPO capacitors for the timing capacitor. In addition to tolerance of the capacitor, X7R capacitors do not have a good voltage coefficient. COG/NPO capacitors are also better in regards to the voltage coefficient. 

Is this issue seen on many boards and devices? Is it possible to try replacing the capacitor with a higher quality capacitor to see if this improves?

Best Regards, 

Chris Featherstone 

Hi Chris,

Good evening and thank you so much for your kind reply.

I have forwarded your comments to our Japan team to check with the customer.

I will get back to as soon as advised.

Thank you again and it'll be grateful if you could kindly provide your continuous support.

Hi Mike,

Good evening.

Chris kindly relied back to me and I will gather more information and will get back to both of you once advised from our Japan team.

In meantime, it'll be great if you could kindly provide your support for the questions 1 and 2...

1. Will this device sealed under atmospheric pressure or under reduced pressure?

    (RGA is tested as if the device is sealed under atmospheric pressure)

2. Are there any reports of anomaly or malfunction for this date code (1935A)

I'm so sorry for taking your time for this but I do really need your support to get the customer project going.

Thank you!

Kind Regards,

Yohei

Hi Chris,

Good morning from Southern California.

Please allow me to ask a following question regarding your comment kindly provided previously.

The customer used same condenser and ended up with a different results.

So in other words, the devices are not defected at all but the results may differ by using EM and FM devices since both have a slightly different specs...

It'll be grateful if you could kindly share your knowledge.

Thank you for your kind support.

Kind Regards,

Yohei

SE555M_MIL.pdfSE555-SP.pdf

Hi Yohei,

Sorry, but, I'm not following here.  When you say "customer used the same condenser and ended up with a different results" - we don't know exactly what you mean by the "condenser" - is this the application the device is used in?  So they tried a different SE555 with the same application, and the results were different?  Did they measure the frequency for both cases?

Also, we don't know what is meant by "EM" and "FM" devices-  are those different versions of 555 timers?

Yes, we do think that the 555 timer will show some variation.  Keep in mind the spec. for trigger threshold can span from 1.3 to 1.8 V - this is a variation of 16% from a nominal of 1.55 V.  So, the 555 timer alone will show variation in the frequency between different devices and lots.  In addition, using a 10% capacitor adds further variation. The customer should keep this in mind, that with this much range in the tolerance between just these two components, there is a realistic probability that the frequency variation can be as high as 20%.

Regards,
Mike

Hi Mike,

Thank you so much for the follow up.

The "same condenser" that I tried to explain was the customer used same condenser in their design but used the two different devices (SE555M and SE555SP) to see how it goes and ended up in different results (I believe the customer measured frequencies in both cases)

Therefore, we though the differences between two results were caused by two different devices since they have a slightly different specs.

EM (Experimental Model) that I referred was for SE555M, which is mil-spec and SE555-SP as FM (flight Model) since this one is for space use.

Hope my explanation makes sense,,,

Thank you.

Kind Regards,

Yohei

3652.Frequency with part names.pdf

Yohei,

Thank you for the clarification. We still need more time to look into questions 1 and 2 as these are not typically answered by the Applications Team. We believe that most of the variation the customer is seeing is due to the large tolerance value on the capacitor in the design. We will continue to try and find answers for questions 1 and 2. 

Best Regards, 

Chris Featherstone

Hello Chris,

Thank you so much for your kind reply.

Yes, it'll be great if you could kindly provide your continuous support for question 1 and 2.

Also, would you please kindly provide your knowledge for SE555M and SE555SP ABA test result (or am I expecting follow up from Mike?)

Thank you again for your kind support.

Kind Regards,

Yohei

Yohei,

We are still trying to get answers for questions 1 and 2.  I'll be pursuing this, we are asking internally.  Chris will help with technical support.

I do think the two results can be caused by two different devices.  This could be a result of differences in the threshold voltages.  In the document you've shown, there is only one "measured" value, though - can you send us the "measured" value for both devices and scope shots?  I see the scope shot for the second device but not the first.  If there is differences in the threshold voltages, we should be able to see that the ramp voltages have different maximum and minimum values.

Regards,
Mike

Hello Mike,

Thank you so much for your reply.

Regarding question 1 and 2, roger that!

I have sent your comment to our Japan team to check with a customer for your request regarding the measured values.

I will get back to you in ASAP when I receive any feedback.

Thank you again for your kind support.

Kind Regards,

Yohei

Hello Mike,

Just spoken to our Japan team regarding your request for the scope shot.

Are you referring to the scope shots for Pin-3 and Pin-6 of SE555M (Military Grade) since we have submitted scope shots for SE555SP (Space Garde)?

It'll be grateful if you could kindly provide your comment since customer dead line is closing by which is 6/15/2022...

Sorry for the push and thank you for your kind support.

Kind Regards,

Yohei

Hello Yohei,

Yes, it would be helpful to see measured values of both devices in order to see if the trigger and threshold values are different. This can be done by measuring both the timing capacitor and the output waveforms together on the same plot. Specifically we would want to see 

1. An oscilloscope capture of the SE555M timing cap and output with cursors measuring the voltage level at the top and bottom of the timing capacitor waveform. 
2. Same as #1 for the SE555SP

An example is shown below. The cursors for the measurement should be placed on the peak and bottom the timing capacitor waveform for both measurement 1 and 2. I have highlighted these points of interest in red below. This will highlight the level of of both trigger and threshold voltage trip points for each device and we can see the difference between the devices. 

Best Regards, 

Chris Featherstone

Hello Chris,

Thank you so much for your kind reply.

I have forwarded your comment and request to our Japan team.

I will come back to you in ASAP as I am advised.

Thank you again for your kind support!

Kind Regards,

Yohei

Hello Chris,

I have sent the request to customer for the scope shots for both MIL and Space parts and will get back to you as soon as advised.

In meantime, would you please kindly advise for questions 1 and 2 below?

1) Will this device sealed under atmospheric pressure or under reduced pressure?

    (RGA is tested as if the device is sealed under atmospheric pressure)

2) Are there any reports of anomaly or malfunction for this date code (1935A)

Sorry for the push... but it'll be great if you could kindly provide your support!

Kind Regards,

Yohei

Hello Chris,

Please allow me to attach two files received from customer for the scope shots of both MIL and Space parts.

Hope it helps.

Also, we were informed from customer that we need to resolve all the questions (including question 1 and 2) by 6/20 since the customer is to report to  JAXA.

1. Will this device sealed under atmospheric pressure or under reduced pressure?

    (RGA is tested as if the device is sealed under atmospheric pressure)

2. Are there any reports of anomaly or malfunction for this date code (1935A)

Sorry for the push but we really do need your kind support to conclude the case till then.

JM38510/10901BPA
Power Supply voltage 4.903V
Pin6 MaxV 3.34V
Pin6 MinV 1.53V

5962-9855501VPA
Power Supply voltage 4.994V
Pin6 MaxV 3.41V
Pin6 MinV 1.59V

Resistance at R4 is confirmed 221Ω with multimeter.

Thank you for your kind support.

Kind Regards,

Yohei 

Yohei,

Looking at the supply voltage difference it looks like these measurements were on two different boards? Either way there is a 2.07% difference for the threshold values and another 3.85% difference for the trigger values. This part to part variation combined with component error would explain the difference that is seen. 

Best Regards, 

Chris Featherstone

Hi Chris,

Thank you so much for your comment.

I have forwarded your comment to Japan team.

Please allow me to get back to you once I receive feedback form them.

Thank you again for your kind support.

Kind Regards,

Yohei

Hello Chris and Mike,

Hope you're well.

Sorry for the push but it'll be great if you could kindly provide your support for the questions below as well.

1. Will this device sealed under atmospheric pressure or under reduced pressure?

    (RGA is tested as if the device is sealed under atmospheric pressure)

2. Are there any reports of anomaly or malfunction for this date code (1935A)

I'm truly sorry for the push and big thanks for all the kind support.

Kind Regards,

Yohei

Hello Chris and Mike,

Hope you're well.

Sorry for the push but would it be possible for you to kindly provide your support for the questions below?

1. Will this device sealed under atmospheric pressure or under reduced pressure?

    (RGA is tested as if the device is sealed under atmospheric pressure)

2. Are there any reports of anomaly or malfunction for this date code (1935A)

Once again, sorry for the push but really needing your support so that customer could proceed their project...

Thank you so much for your kind support.

Kind Regards,

Yohei

Hi Yohei,

This morning I discussed with an expert about the package technology.  He clarified answer #1: the device is NOT sealed inside a chamber with reduced pressure.  The seal is formed by melting of a glass coating (frit) at high temperatures with dry airflow surrounding the device.  Once the device cools, the reduced temperature then creates reduced pressure in the sealed package chamber.  But, the oven that this occurs in is open, meaning that it only operates at room atmosphere/pressure.

We are still looking into item #2, and will get back to you ASAP.

Regards,
Mike

Hello Mike,

Thank you so much for kindly discussing with your team and comments.

Please allow me to get the comments back to customer via our Japan team.

It'll be great if you could kindly advise for question #2.

Thank you so much again for your kind support and looking forward to hearing from you soon.

Kind Regards,

Yohei

Hello Mike,

Please allow me to ask you additional question.

We have received RGA report from customer with another question regarding hydrogen level.

RGA report is stating 0.09vol.% of hydrogen detected and customer is wondering how and how much hydrogen may be sealed inside the cavity during the assembly process.

As you know, oxygen + hydrogen = water, which may lead to moisture level increase inside the cavity and this is the reason for their question.

Of course we are not looking for the exact amount of hydrogen sealed inside the cavity, but it'll be great if you could kindly provide us comment such as "hydrogen level is less than 0.1vol.%" and which process may have a possibility for hydrogen sealed inside the cavity.

I'm so sorry to trouble you but hope I could have your kind support.

Kind Regards,

Yohei

Hi Yohei,

Unfortunately we can't support any request for further information on that topic. There is "dry" air used when the assembly occurs, and steps are taken to try to minimize moisture in the package, but we can't ensure any level of hydrogen inside the package.  Sorry we can't be of more help here.

Regards,
Mike

Hello Mike,

Thank you so much for kindly providing your comment for new question.

It'll be great if you could kindly provide your support for question #2 regarding anomalies and malfunction cases for this date code 1935A.

Thank you again for your warm consideration.

Kind Regards,

Yohei

Hi Mike,

I'm so sorry for belated reply.

Thank you so much for kindly providing information.

I have forwarded information to our Japan team and they are currently working with a customer.

I'll get back to you as soon as I receive a word for next action.

Thank you again for your kind support.

Kind Regards,

Yohei

Hi Yohei, 

Ok, let me know if more questions com up.

Regards,
Mike

Hi Mike,

Hope you're well.

I did receive more questions as below and hope you could kindly provide your support.

1) Do TI recognized this DC:1935A part a good part (very obvious it is a good part since TI have shipped it with C of C but it'll be great if you could kindly confirm)

2) Please kindly provide the volume inside the cavity (if the cavity volume is below 0.01cc, we could apply correction factor for RGA to pass the test)

3) Please kindly provide the oven temperature when sealing the device (you've kindly advised no further information can't be provided but oven temperature is needed in order to use the correction factor for RGA)

Below are the calculation.

RGA Result : 0.87vol.%

MIL-STD-883 TM 1018 criteria : below 0.5vol.%

MIL-STD-883 TM 1018 appendix (attached file) correction facor

   Ct = (Tr + 273)/(Ts + 273)

   Tr = Room Temp, Ts = Sealing Temp.

   Vapor (corrected) = Vapor (measured) X Ct

<Calculation Result>

If room temp. 25C, sealing temp 400C,

Ct = (25 + 273)/(400 + 273) = 0.443

Vapor (corrected)= 0.87vol% ×　0.443 = 0.39vol%

RGA result of 0.39vol.% is below 0.5vol.% (Meeting MIL-STD-883 TM 1018 criteria)

So sorry for asking you a lot of questions but hope you could kindly provide your support.

Thank you.

Kind Regards,

YoheiMIL-STD-883K_CHG-3-1_method1018.10抜粋.pdf

Yohei,

I don't know how much of this information we have available but I will see what I can find.   I will target to try to get information back to you by Friday but many people are out due to holidays, so it could be longer.

Regards,
Mike

Hi Mike,

Thank you or your kind reply and warm consideration.

Yes, it'll be great if you could kindly provide information once you receive comments from the team.

Thank you so much again for your kind support and please have a great rest of your day.

Kind Regards,

Yohei

Hi Mike,

Hope you're well.

Have you received any word form the team?

It'll be grateful if you could kindly provide us comments if there are any.

I'm truly sorry for the push...

Thank you for your kind support.

Kind Regards,

Yohei

Hello,

Michael is currently the primary contact for your SE555-SP RGA inquiry and is currently on personal time. In his absence, I will try to point you into a direction that may answer your questions about the criteria met under the QML Class V specification. 

Here is a link to the SMD which lays out the compliance of the part: https://landandmaritimeapps.dla.mil/Downloads/MilSpec/Smd/98555.pdf

Here is a link to what the TI QML Class V covers: https://www.ti.com/lit/an/sboa141a/sboa141a.pdf?ts=1657219444974&ref_url=https%253A%252F%252Fwww.google.com%252F

If you look on page 5 the internal water vapor test is done to MIL-STD-883 1018 standards.

Michael is scheduled to return in approximately two weeks. If you would be able to wait for his reply to your latest questions that would be greatly appreciated.

Regards,

Cas

Hello Cas,

Hope you're well and thank you so much for your kind reply as well as information.

The problem we have is that the part exceeded MIL-STD-883 TM1018 at the RGA test and we are currently looking for the volume inside the cavity and oven temperature at the sealing process so we could use correction factor for RGA.

It'll be great if you could kindly provide your support for below since Mike is on personal leave...

1) Do TI recognized this DC:1935A part a good part (very obvious it is a good part since TI have shipped it with C of C but it'll be great if you could kindly confirm)

2) Please kindly provide the volume inside the cavity (if the cavity volume is below 0.01cc, we could apply correction factor for RGA to pass the test)

3) Please kindly provide the oven temperature when sealing the device (you've kindly advised no further information can't be provided but oven temperature is needed in order to use the correction factor for RGA)

Below are the calculation.

RGA Result : 0.87vol.%

MIL-STD-883 TM 1018 criteria : below 0.5vol.%

MIL-STD-883 TM 1018 appendix (attached file) correction facor

   Ct = (Tr + 273)/(Ts + 273)

   Tr = Room Temp, Ts = Sealing Temp.

   Vapor (corrected) = Vapor (measured) X Ct

<Calculation Result>

If room temp. 25C, sealing temp 400C,

Ct = (25 + 273)/(400 + 273) = 0.443

Vapor (corrected)= 0.87vol% ×　0.443 = 0.39vol%

RGA result of 0.39vol.% is below 0.5vol.% (Meeting MIL-STD-883 TM 1018 criteria)

Thank you again for your kind support.

Kind Regards,

Yohei

Hi Yohei, 

I will be replying to your inquiry since Mike is out of the office. 

SE555-SP should have MSL-1 specification, even though our material content website did not specify it in details. These parts should be all encapsulated from a single fab testing house. As MSL-1 encapsulant, the epoxy molding compound should have the minimum or low moisture absorption properties.  

-RGA Result- 0.87vol% against RGA requirement 0.5vol% (MIL-STD-883, TM1018)

0.87vol% implies that the SE555-SP part has the internal moisture content above 5000ppm. Can you tell us how the product is stored, tested and exposed in actual conditions? It seems that the figures are a bit high. RGA is a different technique to gauge the internal moisture content from MSL, which was developed in the late 1960. Are we talking about a fresh SE555-SP IC, in RGA measurement out of a manufacture sealed package?

If the SE555-SP has indeed high moisture level content, engineers can follow IPC/JEDEC J-STD-020C bake procedure to remove moisture from the package. It is typically down at 125C +5C/-0C for a period of 24 hours minimum. 

https://www.ipc.org/TOC/IPC-JEDEC-J-STD-020E.pdf

Even with MSL-1 rating, it still has to follow JEDEC storage recommendation for the class of the encapsulant,  

If this is a different moisture level concern, please let us know. 

MIL-STD-883 TM 1018 appendix (attached file) correction factor --> If room temp. 25C, sealing temp 400C

Please let us know the above inquiry, and I will help you to calculate the correction factor, if necessary. 

IC's epoxy molding compounds are unable to withstand 400C's sealing temperature. I do not know the specific curing temperature over the production line, but it is likely near 125C-150C range (guess). I can find it out for you if it is required. 

Please let us know if you have additional questions.  

Best,

Raymond

Hi Raymond,

Thank you so much for kindly providing your knowledge as well as warm consideration.

Please allow me to check with our Japan team for question 1: how the product is stored, tested and exposed in actual conditions.

For question 2: Are we talking about a fresh SE555-SP IC, in RGA measurement out of a manufacture sealed package?, Yes, the RGA has done with in DPA so we are talking about a fresh sealed packaged SE555-SP IC.

Also, it'll be grateful if you could kindly accept the request for oven temperature.

I will come back to you once I receive a comment from Japan team for question 1.

Thank you again for your kind support and warm consideration.

Kind Regards,

Yohei 

Hi Yohei,

Also, it'll be grateful if you could kindly accept the request for oven temperature.

Please see the captured image and attached file. 

J-STD-020C Proposed Std Jan04.pdf

If you have additional questions, please let us know. 

Best,

Raymond

Hi Raymond,

Thank you so much for your quick reply.

I think I made a confusion and I'm sorry.

I meant to ask you for the oven temperature for your kind offer below.

"I do not know the specific curing temperature over the production line, but it is likely near 125C-150C range (guess). I can find it out for you if it is required."

Would it be possible for you to kindly check and advise the specific oven temperature of the production line?

Thank you again for your kind support.

Kind Regards

Yohei 

Hi Yohei, 

Would it be possible for you to kindly check and advise the specific oven temperature of the production line?

Ok, I will check it with process engineer next week. 

The typical Tg of the epoxy molding compounds are at approx. 130C. At 400C, most epoxy compounds will start to decompose. 

Best,

Raymond

Hi Yohei,

SE555-SP is in Ceramic Dual Inline Package (CDIP). It was my mistake to assume that sealant is epoxy molding compound.  

Since SE555-SP is in CDIP package, it should not have moisture absorption issues. So I was wondering why it failed RGA test, which is a moisture absorption test. 

I do not have sealing temperature for the CDIP. Since it is ceramic, it is likely sealed with low Tg glass, which the sealing temperature will be high (I do not found the figure yet).  The ceramic sealing temperature close to 400C is possible, but I do not understand the RGA test result.  

Best,

Raymond

Hi Raymond,

Thank you for your comment.

As I have requested sealing oven temperature to Mike, would it be possible for you to kindly check the oven temperature when the device is sealed so we could use correction factor to re-calculate RGA result?

Thank you so much again for your kind support.

Kind Regards,

Yohei

Hi Yohei,

The low Tg glass sealing temperature in SE555-SP is not specified in our database. We have to go to the manufacturing to request the information, which it will take some time to obtain the information.  

The sealing temperature for CDIP should be anywhere between 350C to 435C range as shown in Nippon Low Tg Glass datasheet. There are other companies such as Schott and YEK Glass companies etc.. The working temperature of the sealant materials are generally above 300C (from what I see for the CDIP hermetic sealing application). 

Even we assume the sealing temperature is 300C, the vapor correction factor is calculated to be at approx. 0.452vol% < 0.5vol% (you may back calculate the sealing temperature and you will realize that the SE555-SP's corrected RGA figures meet MIL-STD-883 TM 1018 criteria). 

I will post the actual sealing temperature data once we are able to obtain the information from the manufacturing. 

Best,

Raymond

Hi Raymond,

Thank you so much for the information and it'll be great if you could kindly request the oven temperature to manufacturing.

Alos, would it be possible for you to kindly provide your comment for 2 previously submitted questions?

1) Do TI recognized this DC:1935A part a good part (very obvious it is a good part since TI have shipped it with C of C but it'll be great if you could kindly confirm)

2) Please kindly provide the volume inside the cavity (if the cavity volume is below 0.01cc, we could apply correction factor for RGA to pass the test)

In meantime, please allow me to forward the information kindly provided to our Japan team.

Thank you again and it'll be grateful if you could kindly provide your comment if there are any news.

Kind Regards,

Yohei

Hi Yohei,

Ok, I will request the information from the manufacturing, but it may take more than couple days (could be up to a week). I will post the information once I have the reply. 

Best,

Raymond

Hi Raymond,

Thank you!

Kind Regards,

Yohei

Hi Yohei,

I am getting a partial reply for your inquiry. 

The Glass lid seal profile is high temp is 430-440 Degree’s C . The glass transition temp should be around 390-400C

I will update the cavity of SE555-SP in CDIP. . 

Best,

Raymond

Hi Raymond,

Thank you so much for your kind reply and please allow me to forward the information to our Japan team.

It'll be great if you could kindly advise the cavity volume once confirmed.

Thank you again for your kind support!

Kind Regards,

Yohei