LMG1020: LiDAR application on LMG1020

li cunxu

Prodigy 120 points

Part Number: LMG1020

Hi，TI expert

I have a LiDAR application question, can the lmg1020 drive the laser directly without GaN FET?

over 1 year ago

0 Ritesh Oza over 1 year ago

TI__Intellectual 1880 points

Hi Ii,

Thanks for reaching out to us for your gate driver needs.

LMG1020 is a GaN FET driver. If the laser module has integrted GaN FET and that needs to be driven then LMG1020 should be able to drive it.

But, LMG1020 is not designed to drive the laser diode.

Please let us know if you have any other question.

Thanks.

Ritesh

0 li cunxu over 1 year ago in reply to Ritesh Oza

Prodigy 120 points

Hi Ritesh,

thanks for your answer. I have another question about LMG1020.

I see your schematic of LMG1020 evaluation board. There are GND and PGND in schematic. Do GND and PGND need to be joined together by a resistor or a ferrite bead?

Thanks.

0 Rubas Khalid over 1 year ago in reply to li cunxu

TI__Expert 8791 points

Hi Li,

The PGND and GND are connected internally via star-connection.

Thanks,
Rubas

0 li cunxu over 1 year ago in reply to Rubas Khalid

Prodigy 120 points

Hi Rubas,

Your mean that GND and PGND are connected in the PCB via star-connection? Because I don't see the star-connection in the schematic.

If it's in the PCB, can you show it in the PCB using pic.

Thanks

0 Rubas Khalid over 1 year ago in reply to li cunxu

TI__Expert 8791 points

Hi Li,

Yes, it is connected in the PCB layout. It's described in the table found in section 7.3 of the LMG1020-EVM User's Guide. Let me know if this table helps or if you need more information.

Thanks,
Rubas

0 li cunxu over 1 year ago in reply to Rubas Khalid

Prodigy 120 points

Hi, Rubas,

Thank you for your answer.

0 li cunxu over 1 year ago in reply to Rubas Khalid

Prodigy 120 points

Hi, Rubas

I do not find the star-connection in the PCB layout. Please show me where is the connection.

My understanding is that the pin2/4/6 of Q1 are connected together, so GND and PGND are connected. Is that right?

Thanks

0 Rubas Khalid over 1 year ago in reply to li cunxu

TI__Expert 8791 points

Hi Li,

Yes, pins 4, 6, 7 (PGND), and 2 (GND) of that GaN FET each have a via connecting to the same layer in the PCB. Star-connection is more so a metaphorical term these days.

Thanks,
Rubas

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LMG1020: LiDAR application on LMG1020