TPS23882B: EEPROM request issue

Tommy Tzeng

Part Number: TPS23882B
Other Parts Discussed in Thread: LM5017, LM5019

Hi Sir,

as far as i know , that TPS23882B1 has autonomous mode and does not need SRAM can to be compliant to the standard_802.3at and .bt , right?

customer want to do dumb switch soluiton, i think can be made the 882b1 version. no need nay MCU and EEPROM, right?

over 2 years ago

+1 Raymond Lin over 2 years ago

TI__Mastermind 34126 points

Hi Tommy,

TPS23882B1 is a Type-3 .bt ready PSE device and as you mentioned, it does come with autonomous mode which does not require a host/MCU in order to operate (pin 52 of the IC). In autonomous mode it will be compliant with .bt standards (as well as .af and .at) but will not come with PPM features.

You can find more information on section 9.6.2.13.1 (page 52) of the datasheet on how to operate the PSE in autonomous mode.

I also recommend taking a look at this application note on using the PSE in autonomous modes and its benefits: https://www.ti.com/lit/an/slvaf77/slvaf77.pdf?ts=1676592466612&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS23882B

Thanks and Regards,
Raymond Lin

0 Tommy Tzeng over 2 years ago in reply to Raymond Lin

Genius 5690 points

Hi Ryamond,

thanks for your help,

may we know about this schematic is correct about TPS23882B version?

4 PORT switch add POE_AT_TPS23882B_20230302 .pdf

0 Raymond Lin over 2 years ago in reply to Tommy Tzeng

TI__Mastermind 34126 points

Hi Tommy,

I'll look into the schematic and provide feedback, when does the customer need to hear back by?

Also can you provide information on who is the customer and what is their project/design?

Thanks and Regards,
Raymond Lin

0 Tommy Tzeng over 2 years ago in reply to Raymond Lin

Genius 5690 points

Hi Ryamond,

the informance from customer as foolows:

I am Josh from Nuvoton ,we use TPS23882B to build a POE daughter board. This POE board is used to check our MCU and can be used as a reference board for our customers.

Can you provide feedback next week?

0 Raymond Lin over 2 years ago in reply to Tommy Tzeng

TI__Mastermind 34126 points

Hi Tommy,

Thank you for the information, I'll have the schematic review completed by next week!

Thanks and Regards,
Raymond Lin

0 Tommy Tzeng over 2 years ago in reply to Raymond Lin

Genius 5690 points

Hi Raymond,

any suggestion or update, thanks.

0 Raymond Lin over 2 years ago in reply to Tommy Tzeng

TI__Mastermind 34126 points

Hi Tommy,

Apologies for the delay in response, please see below my comments:

1. I highly recommend to use a buck converter instead of a resistor divider to achieve the 3.3V or VDD pin. VDD only has a absolute maximum rating of 4V and only using a resistor divider from 54V can cause issues/damage to the PSE as well as other pins that uses 3.3V such as Reset and OSS. I recommend using the LM5017 or LM5019 as this has adjustable UVLO thresholds that our PSE requires in order for it to power on properly and accurate output voltage when bucking down.

LM5017: https://www.ti.com/product/LM5017

2. On the AUTO pin, attach a 10nF cap between AUTO pin and GND, see below for datasheet description and our daughtercard schematic.

3. Between POE_Px_N and DRAINx we recommend putting in a port fuse with the requirements below:

Where the fuse will be implemented:

4. For unused SENx we recommend grounding these pins. For DRAINx these can be either left open or grounded, leaving it open and slightly reduce power consumption.

5. Double check and make sure the NFET in used matches the requirements shown here:

Please let me know if you have any additional questions or concerns!

Thanks and Regards,
Raymond Lin

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TPS23882B: EEPROM request issue