Dear TI expert,
As shown in TPS70933DBV datasheet, there is an internal 6.5V Zener diode, do you have the allowed current of 6.5V Zener diode ?
Hope to get your feedback ASAP.
Thanks in advance.
Xiangdong.
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Dear TI expert,
As shown in TPS70933DBV datasheet, there is an internal 6.5V Zener diode, do you have the allowed current of 6.5V Zener diode ?
Hope to get your feedback ASAP.
Thanks in advance.
Xiangdong.
Hi Xiangdong,
Do you know what Voltage they are using on this EN pin?
Please make sure that the EN current does not exceed 1.5uA, as stated by the datasheet, excessive current will destroy the device.
Best,
Edgar Acosta
Hi Edgar Acosta,
Thanks. I make a destroyed test to check the failure mode, as shown below.
And I found that the EN is about 12V, but the output is still 3.3V. I don't know why is not ~6.5V or 7V ?
And then remove 1K resistor , EN pin is still workable.
Hi Xiangdong,
To answer why you are getting 3.3V instead of 6.5 or 7V, the device is a fixed output voltage LDO and its output is a 3.3V, therefore, assuming we are not trying to create failure, you will get a 3.3V output.
When you remove the 1K resistor, are you still tying EN to IN?
Best,
Edgar Acosta
Hi Edgar Acosta,
Thanks.
I didn't connect EN to IN directly, but use 1K resistor, and the EN pin is ~12V. I don't know why EN is not ~6.5V or 7V , but ~12V.
When I remove 1K resistor btw EN and IN.
- I use a pull-down resistor to connect EN to GND, the output is ~0V.
- I use a pull-up resistor to connect EN to 15V, the output is 3.3V.
That's why I said EN is still workable.
BRs,
Xiangdong.
Hi Xiangdong,
It looks like the zener diode survived, however, this might not be repeatable. Let me see if I can find more information in regards this. Please allow 1-2 days for a response.
Best,
Edgar Acosta
Hi Edgar Acosta,
Thank you for your support. Hope get your new response.
BRs,
Xiangdong
Hi Xiangdong,
Have you tried this destructive test with several devices? Also, is it possible to provide some scope shots when the tests are being done?
This could be a case were the Zener survived, however, it does not imply that it is repeatable across devices.
Best,
Edgar Acosta
Hi Edgar Acosta,
Thanks for your information. I had tried this destructive test more than 5 pcs. But only used multi-meter to measure the EN pin and output.
Unfortunately, I am work from home and can get these scopes in these days. I will try to send these scopes if possible.
BRs,
Xiangdong.
Hi Xiangdong,
Thank you for sharing this information. Have all the 5 parts survived? Also, have all of them shown the same behavior i.e all of them showing 12V @ EN?
Best,
Edgar Acosta
Hi Edgar Acosta,
Yes, 5 parts are survived. Related Vin and EN signal show below.
BRs.
Xiangdong.
Hi Xiangdong,
Thank you for sharing the scope shots.
We normally are very conservative with the numbers we place in our data sheets, meaning, that we give some headroom for abnormal situations. Having said that, we strictly recommend customers to operate within the Recommended Operation Conditions, as we cannot guarantee proper functionality beyond what is specified in our Data Sheet. Furthermore, operating the device beyond the Abs max values will degrade and/or damage the part.
If the intent is to destroy the device, try increasing the Voltage and/or the current flowing through Enable Pin, until the device stops functioning.
Best,
Edgar Acosta
Hi Edgar Acosta,
Thank you for your feedback.
Of course, we will follow the
Datasheet.
BRs,
Xiangdong