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Jon's Imaginarium – Bi-Directional Level Shifter

Visitor

Well-Known Member
Since the response to these posts has been underwhelming, I will continue :)

Often, it is necessary to interface 5 volt and 3.3 volt systems; a sensor may not be 5 volt tolerant, but other parts of the system may need to run at 5 volts. This bi-directional level shifter circuit may be used for I2C and SPI interfaces or general digital I/O. It uses only one mosfet and two resistors (per channel), so it needs a very small footprint on a pcb.

The first reference explains this circuit. The second covers this circuit but goes on to explain alternatives where is necessary to isolate an unpowered bus section and other advanced cases.

NXP Application Note AN10441: Level shifting techniques in I2C-bus design

Phillips Application Note AN97055: Bi-directional level shifter for I²C-bus and other systems


If you find these posts useful, a comment or like would be appreciated.

Schematic_Bi-Directional Level Shifter per Philips Ap Note AN97055.jpg
 

throbscottle

Well-Known Member
Clever. I actually wanted something like this a long time ago but then it became irrelevant anyway so I never solved it.
 

JimB

Super Moderator
Most Helpful Member
Since the response to these posts has been underwhelming, I will continue :)
Hmmm..

I am not one for effusively gushing praise and plaudits at the drop of a hat, but I do look at your Imaginarium posts and find them interesting.

JimB
 

Visitor

Well-Known Member
Hmmm..

I am not one for effusively gushing praise and plaudits at the drop of a hat, but I do look at your Imaginarium posts and find them interesting.

JimB
Thank you. Just looking for a little feedback to know if they are appreciated.

I am often intrigued by circuits or components I come across that I may not have any immediate need for but suspect may be useful at some point, so this is a way to share and archive those things.
 

Mickster

Well-Known Member
Most Helpful Member
Since the response to these posts has been underwhelming, I will continue :)
Please do.
You have over a hundred views on each Imaginarium thread made since Tuesday.
Members are looking.
Thanks for your contribution.
 

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