LMG1025-Q1EVM: LMG1025-Q1EVM

Joseph Schneider

Part Number: LMG1025-Q1EVM

I am trying to pulse a laser diode at the 1-2 nanosecond pulse width. However, there is a long tail the lengthens the pulse to about 10ns. The rise time is 1ns but the tail drags it out to 10ns. What could be causing the tail to be so long? Do you have any recommendations to reduce the tail so the pulse width is within the 1-2ns range. The input pulse into the board is 65ns.

Thank you

over 2 years ago

0 Leslie Marquez over 2 years ago

TI__Genius 9301 points

Hi Joseph,

Welcome to the forum! Could you please clarify on which test point are you measuring the signal you mentioned?

Regards,

Leslie

0 Joseph Schneider over 2 years ago in reply to Leslie Marquez

Prodigy 10 points

Hi Leslie,

I am measuring the output of the laser diode connected to the board using a photodiode.

Thank you,

Joseph

0 Leslie Marquez over 2 years ago in reply to Joseph Schneider

TI__Genius 9301 points

Hi Joseph,

One thing we recommend is to first test the board with a resistive load equivalent to the diode that you are going to use and make sure that you get the pulse you want at the output of the driver. Once you have the desired pulse at the gate of the FET, then you can remove the resistors and install the diode. You can find detailed procedure in section 4 "EVM Operation Out-of-the-box" in the EVM's user manual: https://www.ti.com/lit/ug/sluuc20b/sluuc20b.pdf

Please try this and let us know if you are still having issues.

Best regards,

Leslie

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LMG1025-Q1EVM: LMG1025-Q1EVM