What does the buffer IC 74AHC125N do ?

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randykarr
 
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What does the buffer IC 74AHC125N do ?

Post by randykarr »

On the tweet a watt Receiver
Why is this IC neeeded ? Just a buffer to help isolate the X-bee from the USB cable ?
thanks
randy

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Re: What does the buffer IC 74AHC125N do ?

Post by adafruit »

thats right! it converts 3-5V signal to 3v signal

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ericzundel
 
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Re: What does the buffer IC 74AHC125N do ?

Post by ericzundel »

Read the soldering instructions:

http://www.ladyada.net/make/xbee/solder.html

Scroll down to the description of the buffer. It allows the 3.3V and 5V logic to interface without letting the smoke out of the 3.3V chips. You might want to find a datasheet for a 74AHC125 and read up on it a bit if you are still curious.

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randykarr
 
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Re: What does the buffer IC 74AHC125N do ?

Post by randykarr »

If you buy the 3 volt TTL to USB cable, the chip is unneeded ?

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Re: What does the buffer IC 74AHC125N do ?

Post by adafruit »

it is not necessary in that case

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