LM5140-Q1: LM5140-Q1,15Pin is breakdown

ZHI HAO GAO

Part Number: LM5140-Q1

when device powed on ，the 15pin of chip （LM5140-Q1）is breakdown，it‘’s short to the ground，butPin16 is OK，i dont kown the reason and how to resolve it，pin15 andpin16 are VCC

besides,the power discrete device is GaN(epc2112),f=2.2MHz

over 6 years ago

0 ZHI HAO GAO over 6 years ago

Prodigy 30 points

this is schematicGnAEpc2014.pdf

0 Arief Hernadi over 6 years ago in reply to ZHI HAO GAO

TI__Mastermind 23845 points

Hi,

Is the capacitor C1 or C2 also shorted to GND?

Also is the diode gets damaged?

Do you have a VCC pin scope waveform during startup and see if there is no overvoltage or undervoltage on the VCC pin?

Thanks

-Arief

0 ZHI HAO GAO over 6 years ago in reply to Arief Hernadi

Prodigy 30 points

the cap(c1 c2) is Ok,,not shorted ,the diode OK ,too.

sometimes ,the vcc is up to 7V,beause some broads are damaged,the waveform will be provided later.

0 Arief Hernadi over 6 years ago in reply to ZHI HAO GAO

TI__Mastermind 23845 points

Ok,

I will add also the product expert in this thread in terms of using this IC with GaN

Thanks

-Arief

0 Timothy Hegarty over 6 years ago in reply to Arief Hernadi

TI__Guru 73402 points

Hi Zhi,

These EPC FETs are sensitive to gate overvoltage. I recommend putting a 5.1V Zener across each boot cap. Also, you will likely need an antiparallel Schottky from GND to SW of each channel as the GaN FET does not have a body diode (causing the SW voltage to swing substantially negative).

Please complete the LM5140-Q1 quickstart calculator for this design and send for review.

http://www.ti.com/tool/lm5140adesign-calc

Regards,

Tim

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LM5140-Q1: LM5140-Q1,15Pin is breakdown