LSF0102: Two Level Shift in Series

Jim CHEN

Part Number: LSF0102
Other Parts Discussed in Thread: SN74AXC2T45, SN74AVC2T245, SN74AXC2T245-Q1

Dear Team,

My customer has one application that require transfer the signal from 3.3V to 1.8V and then transfer from 1.8V back to 3.3V.

Could they put two LSF0102 in series for such application? Is there any concern they should take care in advance?

Thank you.

Regards,

Jim

0 Clemens Ladisch over 4 years ago

Guru 244350 points

This is possible.

The driving device must be able to sink the current though all three pull-up resistors.

0 ShreyasRao over 4 years ago in reply to Clemens Ladisch

Thank you Clemens.

Hi Jim,

You could also consider buffered level translators for the application like the sn74AXC2t45/1T45, unless the signals are bidirectional in nature.

0 Jim CHEN over 4 years ago in reply to ShreyasRao

Thanks for the comments.

Could you help to review the schematic? Thank you.

0 ShreyasRao over 4 years ago in reply to Jim CHEN

Hi Jim,

Dont see any issues on the schematic shown.

For UART interface, you could also consider using the SN74AVC2T245 or the SN74AXC2T245-Q1.

0 Jim CHEN over 4 years ago in reply to ShreyasRao

Hi ShreyasRao,

Thanks for the reply. I saw you recommended SN74AVC2T245 for UART application.

But I want to know what is the difference between it and LSF0102. Is there any benefit if my customer change to SN74AVC2T245?

Thank you.

Regards,

Jim

0 ShreyasRao over 4 years ago in reply to Jim CHEN

UART interface is push pull type of signals, and AVC are buffered level translators suited for such pushpull applications.

LSF is internally a passFET and needs external pullup resistors to achieve level translation.

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