LP87524J-Q1: LP87524J design

Kygo Cheng

Part Number: LP87524J-Q1

Hi,

Such as the SCH below
If I want to directly input 3.3V to LP87524J, and only enable 1V, 1.2V, 1.8V output, how can I change it without affecting the output of PGood? THX

over 4 years ago

0 Tomi Koskela over 4 years ago

TI__Genius 11020 points

Hello,

If you want to use 3.3V input voltage, then you can use LP87524P part number instead. Please see the technical reference manual for more information: https://www.ti.com/lit/ug/snvu663/snvu663.pdf

Thanks.

-Tomi

0 Kygo Cheng over 4 years ago in reply to Tomi Koskela

TI__Expert 6830 points

Hi Team,

They can only use the LP87524J used by the customer’s factory that has been mass-produced. Please help to confirm again. Thanks

0 Tomi Koskela over 4 years ago in reply to Kygo Cheng

TI__Genius 11020 points

Hello,

They can disable the 3.3V buck with I2C write before setting EN pin high. This will prevent the PGOOD triggering.

Thanks,

Regards,

Tomi Koskela

0 Kygo Cheng over 4 years ago in reply to Tomi Koskela

TI__Expert 6830 points

Hi Team,

Is there a mistake in understanding the following figure:
1. PGOOD will be active when EN is not enabled
2. PGOOD will be pulled down if the output voltage is not at the set level after EN enable
3. If the output voltage is modified after EN enable, PGOOD will be pulled low first, and it will become active only after PGOOD_set_delay

0 Tomi Koskela over 4 years ago in reply to Kygo Cheng

TI__Genius 11020 points

Hi Kygo,

Yes you understood correctly. PGOOD is only monitored when bucks are enabled, so when EN is low PGOOD is high. Also during output voltage change the PGOOD goes low momentarily.

Thanks.

Regards,

Tomi Koskela

0 Kygo Cheng over 4 years ago in reply to Tomi Koskela

TI__Expert 6830 points

Hi Team,

Is the attached LP87524J OTP file up to date? THX

snvu663.pdf

0 Tomi Koskela over 4 years ago in reply to Kygo Cheng

TI__Genius 11020 points

Hi Kygo,

Yes it is up to date. Latest one is available from ti.com.

Thanks.

Regards,

Tomi Koskela

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LP87524J-Q1: LP87524J design