[Help] converter voltage 3.3v <-> 5v

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lee_trieu

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Hi all !
I want to design a circuit to conver voltage 3.3V <->5V
hope you help me slove this problem !
thanks all !:roll:
 

hello lee,

If you may please describe following questions i can suggest best level converter to you.

1. Do you want a bidirectional 3.3V <> 5V converter? 3. Is it required for I2C? for I2C you need to have bi-directional level translators
2. What is maximum data rate required?
3. Do you want to implement using discrete components?
4. Do you want the level translator in DIP or SMD package?

regards
 

Thanks you for your answer !
I want to design a bidirectional 3.3V <> 5V converter
it can switch voltage between 3.3V and 5V for microcontrol.
pls help me !!
I want use thís curict for MSP430
 

hello lee,
There are several bideirectional level translator that you may use:

1. If you want to use a translator for i2c or smbus then look at PCA9306 or PCA9547 if you need more channels.
i2c bidirection level translator can be used for general applications but make sure that your application does not requires you over 400kbps data rate

2. Try looking at MAX3372/MAX3393 if your data rate is in Mbps

3. or look at SN74AVC2T4/sn74avc4t245/sn74avc8t245 devices if you can supply direction input to the buffer. These devices are also very fast.

Regards
 


Thanks my friend !
Can you tell me ? how can I do with this IC??
SN 74245

Can I use this IC for my design??? Switch Voltage betwen 3.3V<->5V
 

Hi Lee,

SN74245 has only single supply pin (VCC). and it can operate only down to 4.5V
Therefore you can not use it for 5V to 3.3V level translation. However you can use it to translate your 3.3V singals to 5V as VIH (Minimum Input High Voltage) for this chip is about 2.0V.

For 5V to 3.3V translation you may use poor man's resistor divider network. You may use following online calculator to compute resistor values:

**broken link removed**

For example you may choose R1 as 1.2k and R2 as ~2.33k

Regards
 
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