MCP23008 IO Expander - LCD1602

Now I am reading the datasheet of NXP/TI SN74LVC245A.  I am thnking of using it for shift MCP23008's 3V3 outputs to 5V0 output.  The datasheet guarantees 2.2V, or Vcc - 0.3V = 3V3 -0V3 = 3V if Io = 100 uA.

I found that HC573 need much higher than 2V, though HC04 takes 2V OK.

I think I better check LCD1602's minimum for input high.

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I found that LCD1602's min Vin high is 2V.  So LVC245 is not good enough.

I also read the following report from TI.  It seems that LVC245 is sort of overvoltage tolerant devices.  That means it is OK to use it to translate 5V0 logic level to 3V2, but not vice versa.  I read that there are dual supply devices but I am too lzy to


Texas Instrument Application Report SCEA040–February 2008

Basics of Voltage-Level Translation

http://www.ti.com/lit/an/scea040/scea040.pdf

Slection Guide

http://www.ti.com/lit/ml/scyb018e/scyb018e.pdf

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