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Does the classical 5V <--> 3.3V bidirectional MOSFET interfacing solution exist as a DIP package? Or is the commopn way to place discrete MOSFETs in your circuit? In that case, what are some common low cost through-hole devices that you can recommend for this application? I realize this question has been asked in a few variations already, but I'm looking for practical implementation guidance here.

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The NXP P82B96 bidirectional I2C buffer IC comes in DIP8, among other packages.

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Yes, some people do use discrete MOSFETs; for example, the Sparkfun Logic Level Converter.

There are a few ICs that do bidirectional I2C interfacing, but as far as I know they are all surface-mount. The Bi-directional 3.3v <-> 5v level shifting... thread mentions a few of them. Alas, I don't know of any that are in a DIP package.

Pretty much any nFET can handle the relatively low power and speed required for I2C interfacing; the critical spec seems to be "Vgs(th)". Sparkfun uses a BSS138, a low-cost surface-mount nFET with Vgs(th) of 1.5 V at 1 mA.

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TI Makes a part that will do this:

TXS0102 - 2-bit bi-directional level translator

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  • \$\begingroup\$ It is NOT in a DIP package. \$\endgroup\$ – mjh2007 Oct 20 '11 at 16:52
  • \$\begingroup\$ Have you used the TXS0102 before? I have a few of them. It seems like they will work find for 3.3V <-> 5V logic level shifting. The one thing that concerns me is that OE references Vcca (3.3V) and I would like to be able to control this via logic level on the 5V side. I suppose I could do this with a pull resistor and a transitor, yes? \$\endgroup\$ – Hair_of_the_Dog Jun 13 '16 at 16:45
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    \$\begingroup\$ I have used the TXS0102 before, however I don't recall utilizing the OE line. If I remember correctly we tied this pin to Vcca so that the level shifter was always enabled. I think you could drive the OE line with a transistor that was pulled up to 3.3V with a resistor or if your processor has open collector outputs you would just need the pull up resistor to 3.3V. \$\endgroup\$ – mjh2007 Jun 14 '16 at 13:33

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