TPS53353: Vreg

JDJ

Part Number: TPS53353
Other Parts Discussed in Thread: TPS53355,

From the datasheet, it appears that the Vreg pin should be 5V and will start ramping up when the input voltage is above 2V and is independent of enable pin shown in the graph below.

I am having problems with the Vreg not trying to ramp before the enable pin as shown below.

over 5 years ago

0 JDJ over 5 years ago

TI__Expert 3971 points

I forgot to mention for the above scope grab:

Yellow- 12V

Blue - Vreg

Purple -Enable

Thanks

0 Yuchang Zhang over 5 years ago in reply to JDJ

TI__Mastermind 18510 points

Hi, Which board you used for the test, EVM or customer's board? when the VDD ramp up, same with Vin or..?

Yuchang

0 Yuchang Zhang over 5 years ago in reply to Yuchang Zhang

TI__Mastermind 18510 points

Hi, From the block and some waveform, seems the description is not right, I will forward to lead engineer to double confirm.

Yuchang

0 JDJ over 5 years ago in reply to Yuchang Zhang

TI__Expert 3971 points

Hi Yuchang,

VDD is shorted with Vin which is similar to the EVM.

0 Anthony F over 5 years ago in reply to JDJ

TI__Mastermind 35165 points

Hi Jack,

I have confirmed the startup behavior of the VREG measured here is expected for this device. The VREG LDO requires EN before it comes up. It appears this section in the datasheet was unfortunately incorrectly re-used from a datasheet of a similar device. I have put a note to fix the TPS53353 and TPS53355 datasheets the next time we update them.

Anthony

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TPS53353: Vreg