LP8733: How to use LP873347RHDT

yousuke nasu

Part Number: LP8733
Other Parts Discussed in Thread: AWR1843, AWR1843BOOST, LP87702

１，LP873347RHDT of AWR1843BUSTOS
About how to output 1.8V and 1.24V like U4

２，Designed with reference to AWR1843 BUSTOS
I designed the board but it doesn't work properly
The part corresponding to U4 is not working as designed
I found it to be the cause.

I would like to know how the original AWR1843 BUSTOS u4 works.

over 2 years ago

0 Tomi Koskela over 2 years ago

TI__Genius 11020 points

Hello,

1. I'm not sure what you mean by U4? could you clarify?

You would need to adjust the output voltages through I2C writes to LP8733x registers. The default output voltages don't match with your requirements, so you would need to rewrite the settings.

2. Do you mean AWR1843BOOST EVM? https://www.ti.com/tool/AWR1843BOOST

You are using LP87702DRHBRQ1 in your design?

Thanks,

Regards,

Tomi Koskela

0 yousuke nasu over 2 years ago in reply to Tomi Koskela

Intellectual 880 points

Hello　Tomi Koskela

U4 is LP87702.

How to change the settings of LP8733x
Should I use something?

0 Samuli Piispanen over 2 years ago in reply to yousuke nasu

TI__Expert 4355 points

Hi,

LP873347RHDT and LP87702DRHBRQ1 are not pin to pin compatible devices. In addition, the output voltages and switching frequency differ between those two devices. LP873347RHDT is a 2 MHz switching frequency device whereas LP87702D-Q1 switches at 4 MHz and therefore LP873347RHDT is typically not recommended to be used in radar applications. Output voltages could be changed through I2C writes but the switching frequency cannot be changed.

The register settings for both devices can be found from the respective technical reference manuals.

https://www.ti.com/lit/pdf/snvu679

https://www.ti.com/lit/pdf/snvu593

BR,

Samuli

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LP8733: How to use LP873347RHDT