512Mb flash S25FL512SAGMFI013 failure

[anuragps]

Hi,

I am using  SPI Serial Flash Memory, 512Mbit, SO16 package in one of my design. I am finding many chips getting faulty in 5 to 6 months of operation in field as all access fail post that.

Below is the pinmap of device where pin 4 and 12 are designated as DNU pins. Due to wrong component mounting, these boards had 4.7K pullup to 3.3V rail on these 2 pins.

Can these external pullups on DNU pins impact MTBF cycle of device?

Thanks

Anurag

Tejas Networks

[Yuvraj]

Hi,

Thank you for contacting Infineon Technologies.

Yes, if DNU pins are connected to any signals it might affect the performance of FLASH.

DNU (Do Not Use) pins should be left unconnected and you should avoid connecting these pins to any signals.

Thanks and Regards,

Yuvraj 

[anuragps]

Hi Yuvraj,

Thanks for the reply. If we say performance does it mean functionality or causing physical damage to the chip itself?

Thanks

Anurag

[Yuvraj]

Hi,

Performance means it affects the functionality of FLASH.

Regards,

Yuvraj

[anuragps]

Hi Yuvraj,

As i mentioned in original query, We are finding chip going permanent faulty after 5-6 months of operation. It is not data corruption. This time no read/write access happens. It stops responding at all. Can you check with engineering team if DNU pullups on pin4 and 12 can have this behavior too? Also just one correction, we are using part S25FL512SAGMFIR11 which is with reset input.

Thanks

Anurag

[Yuvraj]

Hi,

Sorry for our previous answer.

As what we confirmed with bonding diagram so these to pin#4, #12 does not boned to any pad so the failure should not related with what customer mounted on these two pin

Regards,

Yuvraj

[anuragps]

Hi Yuvraj,

As per pin bonding diagram, pin 4 and 12 seem NC only. But somehow we have not seen failure on the lots not having these pullups.

Can faulty samples be analyzed for RCA? We can send few of them.

Thanks

Anurag 

[Yuvraj]

Hi,

As we mentioned previously pins 4 and 12 will not cause this issue.

Please let me how you are recreating this issue?

Are you able to reprogram the flash, are you able to read device ID?

Please explain more on what kind of failure (data corruption, device not getting detected or data write) you are getting.

Regards,

Yuvraj 
 

[anuragps]

Hi Yuvraj,

We are not able to recreate issue. These are the boards returning from field as faulty. We are using this as processor boot memory. When we access chip via SPI, there is no toggle on MISO from flash. No access happens here.

Thanks

Anurag

[Yuvraj]

Hi Anurag,

Are you able to read the device ID?

Regards,

Yuvraj

[anuragps]

Hi Yuvraj,

We don't get any output from flash including chip ID.

Thanks

Anurag

[Yuvraj · Accepted solution]

Hi Anurag,

If you want to have FA on the device, please contact your distributor where you got these devices.
The distributor will raise the FA case with Infineon.

Regards,

Yuvraj