LMR36503-Q1: Pin FMA Inquiry - VCC to BOOT short

Andy Snawerdt

Part Number: LMR36503-Q1
Other Parts Discussed in Thread: LMR36503, LMR36503EVM

Hi Team,

For a VCC to BOOT short, we state that device damage would occur as shown in Table 4-4 below. This device is being used in a BMS system which has a safety goal for prevention of thermal runaway events. Can we confirm that a VCC to BOOT short has no risk of this?

Thanks!

Andy

over 3 years ago

0 Denislav Petkov over 3 years ago

TI__Mastermind 19891 points

Hello Andy,

Can you define what they mean by thermal runaway? Temperature has to stay under certain threshold? No sparks/fires?

Thanks,
Denislav

0 Andy Snawerdt over 3 years ago

TI__Intellectual 2300 points

Hi Denislav,

No sparks/fires.

Regards,

Andy

0 Richard Fu22 over 3 years ago in reply to Andy Snawerdt

TI__Mastermind 31315 points

Hi Andy,

This table discusses functional safety, which refers to whether the part will operate as defined. In this case, with Boot short to VCC, the device will likely be damaged, so you lose the capability to generate the output voltage from the LMR36503. The customer will be responsible in deciding if this will cause a spark/fire.

Regards,

Richard

0 Andy Snawerdt over 3 years ago in reply to Richard Fu22

TI__Intellectual 2300 points

Hi Richard,

Understood that the output voltage will fall, and that it's on the customer to determine whether that would have a system level impact of causing a spark/fire.

This question was more as to whether or not the immediate act of a BOOT to VCC short would cause a short spark.

Regards,

Andy

0 Richard Fu22 over 3 years ago in reply to Andy Snawerdt

TI__Mastermind 31315 points

Hi Andy,

I think whether the part will cause a short spark will be determined on how the VCC pin will be damaged. We can run a test on this and take a look into it. Please expect results in a few days.

Regards,

Richard

+1 Richard Fu22 over 3 years ago in reply to Richard Fu22

TI__Mastermind 31315 points

Hi Andy,

A test has been run. The BOOT and VCC has been shorted on an LMR36503EVM. The device got hot, but there were no fires.

Regards,

Richard

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LMR36503-Q1: Pin FMA Inquiry - VCC to BOOT short