TPS40055: What is the diffirent point between TPS40055 and TPS40051?

Kazuya Nakai59

Guru 20450 points

Part Number: TPS40055
Other Parts Discussed in Thread: TPS40051

Hello guys,

One of our customers is using TPS40051 now for their current products and they are considering replacing the device with TPS40055 because TPS40055 current limitter accuracy(Vos:Offset voltage SW vs ILIM) is

higher than TPS40051 .

Could you tell me whether TPS40055 can be used instead of TPS40051 without PCB pattern changing or not?

Also could you tell me what other different point is between TPS40051 and 55? Is it UVLO addition for VIN low voltage detection?

Your reply would be appreciated.

Best regards,

Kazuya Nakai.

over 6 years ago

0 Frank De Stasi over 6 years ago

TI__Guru 58995 points

I think that is good idea to switch to the TPS40055. The TPS40051 is not reccomened for new designs.

The pin out appears to be the same. The other differences can be found in the data sheet.

0 Kazuya Nakai59 over 6 years ago in reply to Frank De Stasi

Guru 20450 points

Hello Frank,

Thank you for the prompt reply.

I checked both device datasheets, but I couldn't find big difference except VDD parameters(UVLO parameter) on page 6 of TPS40055 datasheet as the follow.

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
UVLO
VDD UVLO, fixed 7.2 7.5 7.9 V
VDD UVLO, hysteresis 0.46 V

These parameters are not in TPS40051 datasheet.

Do these mean that UVLO circuit is added to TPS40055 though TPS40051 doesn't have UVLO which checks VIN voltage?

Could you give me your comment?

Thank you again and best regards,
Kazuya Nakai.

0 Frank De Stasi over 6 years ago in reply to Kazuya Nakai59

TI__Guru 58995 points

I am not 100% about your question. However, I think you are correct.

In any case, I would not use the TPS40051, it is not reccomended for new designs.

0 Kazuya Nakai59 over 6 years ago in reply to Frank De Stasi

Guru 20450 points

Hello Frank,

Thank you very much for your reply.

Could I ask you a few additional questions?

Q1. Can TPS40055 be used for a direct replacement for TPS40051?
Q2. Is any external part needed to change in the replacement case?
Q3. Do you know what "VDD" (UVLO) parameter discribed in the last line of the electrical charactertics table means?

Thank you very much again and best regards,
Kazuya Nakai.

0 Frank De Stasi over 6 years ago in reply to Kazuya Nakai59

TI__Guru 58995 points

I think that they are very close.
You will have to look at data sheet for TPS40055 and follow the guidelines.
The UVLO sets when the device will start-up.

0 Kazuya Nakai59 over 6 years ago in reply to Frank De Stasi

Guru 20450 points

Hello Frank,

Could you please tell me which voltage node the UVLO monitor?

Thank and best regards,
Kazuya Nakai.

0 Frank De Stasi over 6 years ago in reply to Kazuya Nakai59

TI__Guru 58995 points

I believe it monitors the input voltage.

0 Kazuya Nakai59 over 6 years ago in reply to Frank De Stasi

Guru 20450 points

Hello Frank,

Thank you for the reply.

Best regards,
Kazuya Nakai.

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TPS40055: What is the diffirent point between TPS40055 and TPS40051?