5V ADC connect to 3.3V microprocessor

[amburose]

5v to 3.3v adc

i have a problem ADC0808 connect with 3.3V microprocessor...
what are possible solution...
plz reply urgently....


advance thanks

 

[ssss959]

74lvc level shifter circuit

can i know that is the problem ur facing

 

[rajeshkumar123]

reduce 5v to 3.3v resistor

hi,

If the port pins of ur 3.3v uP allows open drain outputs ,Configure port pins connected to ADC as open drain and then use pull up resistors to pull the port pins to 5V.

 

[joby16]

interfacing to a 3.3v adc

Hi Rajesh,

How can you reduce the 5V output of ADC to 3.3V by connecting pullup to 5V. Could you please explain a little more?

Regards,
Joby

 

[rajeshkumar123]

3.3 microprocessor

Hi,

I suggested o/p pins to ADC be configured as opendrain outputs and i sincerely beleive that giving 5V to 3.3 I/p port might not cause any problem its better to check with ur controller datasheet

 

[rowokii]

adc 3.3v

You can use something like this which is designed to interface between 5v and 3.3v logic:

https://www.fairchildsemi.com/pf/74/74LVX4245.html

Cheers

 

[rikie_rizza]

adc with 3.3 voltage output

If its only data out from 5V system, just use a super cheap resistor divider solution. several KHz can work with this setup.

Trust me, I've done it before.

But from 3.3V to 5V, you should use level translator IC.

 

[shortcircuit]

3.3v technik adc

The resistor solution is a good one...
you may also try using a level translator IC like HCF40109
I have done it with this IC and using HCF40109 a working Solution... i have used it for 3.3v <--> 15v

**broken link removed**

one of our frenz silvio helped me in the past.. i am quoting his message for reference...

-----------
cheers,
ShortCircuit
https://www.rewindPlanet.com

You can try HCF40109.

Containd four level shifting circuits with separately enabled TSL output control.
With two chips you solve your bidirectional transfer for four lines.

HCF40109B, unlike other level-shifting circuits, does not require
the presence of the high voltage supply (VDD) before the application of either the low-voltage supply (VCC) or the input signals.
There are no restrictions on the sequence of application of VDD, VCC, or the input signals.
In addition, there are no restrictions on the relative magnitudes of the supply voltages or input signals within the device maximum ratings;
VCC may exceed VDD, and input signals may exceed VCC and VDD.
When operated in the mode VCC VDD, HCF40109B will operate as a high-to-low level-shifter.
On low-to-high level shifter each circuit will shift a low-voltage digital-logic input signal (A, B, C, D)
with logical 1 = VCC and logical 0 = VSS to a higher voltage output signal (E, F, G, H) with logical 1 = VDD and logical 0 = VSS

If the current is not an issue :

**broken link removed**

 

[apv1965]

adc 5v

If you are feeding ur controller the out put of Ur ADC, then do following:
1. check the data sheet of microproccessor for the iput pin compliance for 5 volts. Normally they allow but checkingis must for safty of ur Processor. If it is there the Use it directly without worry
2. If they are not 5 volt compliant then U can do either resistor networking or Level translators. If the processor is critical and the circuit is more critical then I would recommend you to use level translators always. It is more safer and not too much expensive also...

If you need some numbers of level translators U can visit TI site or Maxim site or ST site or NXP. there ar elot more...