TPS26600-02EVM: Chips getting destroyed with 52V and 1.4A after 1 hour

Claudio Leombruni

Part Number: TPS26600-02EVM

Hi
I'm testing the TPS26600-02EVM. I had to change R2/R14 to 1M, R3/R15 to 39k and R8/R20 to 22k because we have to use the board with 48V (20V...55V).

J6/J13, J7/J14: OFF

J4/J11: OFF (Circuit Breaker Mode)

J5/J12: 3-4 (1.5A)

J1/J8, J2/J6: ON

Input: 52V (max 2A power supply)

Output: electronic load (set to 1.3A)

Every thing worked very well, but after about 1 hour the chip was making a "bang" and was destroyed. So I tried also the second channel with the RHF-case, but also this chip was after about 30min destroyed! What I'm doing wrong?

Now I measuring 52V on RTN Plane! Is the problem the electronic load? Need the chip a resistor as load?

We need 7 TPS26600PWP on each device and we start to produce on Jan 18 the first 300 devices.

Thanks for the help

regards
Claudio Leombruni

over 7 years ago

0 Karikalan Selvaraj over 7 years ago

TI__Genius 16305 points

Hi Claudio,
Thanks for posting this question, I am looking into it and will get back at the earliest.
Regards,
Kari.

0 Karikalan Selvaraj over 7 years ago in reply to Karikalan Selvaraj

TI__Genius 16305 points

Hi Claudio,

From the picture, it looks like OUT pin is damaged (OUT-RTN) and that is why RTN plane is seeingg 52V.
Did you use the electronic load in Constant Current mode? This could make out swing negative and damage the IC.

Regards,
Kari.

0 Claudio Leombruni over 7 years ago in reply to Karikalan Selvaraj

Prodigy 30 points

Hi Kari

Yes, the electronic load is on constant current mode. But I did not touch/change anything for 30min and it was getting damaged. Now I ordered new parts and I connect a 50Ohm/50W resistor, let's see what's happening now. I let you know.
Regards
Claudio

0 Claudio Leombruni over 7 years ago in reply to Claudio Leombruni

Prodigy 30 points

Hi Kari

Now with a resistor it works for more than 24h. But was is exactly the Problem with the electronic load in CC mode? Is it save to use the CR or CP Mode?

Thanks

Claudio

0 Karikalan Selvaraj over 7 years ago in reply to Claudio Leombruni

TI__Genius 16305 points

Hi Claudio,

With electronic load in CC mode, device absolute maximum rating can exceed and in the EVM User's Guide, it is recommended to use electronic load in CR mode and not in CC mode.

Yes it is safe to use in CR mode.

Regards

Kari.

0 Lim Sheng Yu68 over 7 years ago in reply to Karikalan Selvaraj

Prodigy 10 points

Hi Kari,

Actually I faced the similar failure as well. My input voltage is 48V. My current limit is 2A. When I performing short circuit test by using electronic load, the IC get burned and it looks exactly like picture posted by Claudio. When I measure Vin to RTN, it is shorted. The short circuit spike current will can ramp up to 50A and last for 30us.

I have tried about 10 times, and I burned 10 IC's. I am wandering is it the spike power kill the IC or is it some inductive kick back kill the IC?

Thanks.

Regards,
Lim

0 Karikalan Selvaraj over 7 years ago in reply to Lim Sheng Yu68

TI__Genius 16305 points

Hi
This could be related but could you share the schematic.
Is there a schottky from OUT to GND, this is recommended (as in EVM).

Regards,
Kari.

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TPS26600-02EVM: Chips getting destroyed with 52V and 1.4A after 1 hour