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AD8275 rail-to-rail output ?

Question asked by Klaus.Schmidt on Jul 30, 2015
Latest reply on Aug 4, 2015 by ScottH

The AD8275 is a level translator with rail-to-rail output.

But if this is true why is there an output swing ?

 

OUTPUT CHARACTERISTICS

Output Swing

(VREF2 = 4.096 V, REF1 and RL connected to GND, RL = 2 kΩ)

 

−VS + 0.048                     +VS − 0.1

 

I want to use this level translator with +Vs = 5V, -Vs = GND, Ref1=Ref2 = 2,048 V, RL = 8kOhm.

The calculated output for -10V input is exactly 0,048 V

 

The design includes a LM7705 to generate the negative supply voltage (-0,232) for the ADC.

I never found a application with -Vs of the AD8275 connected to a negative supply voltage.

Is it allowed to connect the -0,232V fron the LM7705 to the -Vs Pin of the AD8275 ?

If the answer is yes, then I can avoid to scratch with the negative output swing the not really rail-to-rail output limitation.

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