# AD8310 upper output rail and Slope raising

Question asked by RogerC on Mar 25, 2016
Latest reply on Mar 31, 2016 by RogerC

Hi guys,

First:

What is the absolute upper rail of the output swing at +5V supply?

The question is because if Slope is raised adding a resistor between pins 4 and 6. Can achieve higher output voltage ? or stays in 2,6V maximum always ? In pspice model this level is 4V when Vcc=+5V, is this right?

And second:

Vout=S·20·log(Vin/Vx) as datasheet says.

With Vx=4uV and S=24mV/dB, The input voltage must be at less 70,7uV (-83dBV) for maintain error low, and it will produce 599mV DC output. So output levels lower than 599mV have error and be unusable. Right ?

When Slope is raised, the minimum input level voltage keeps equal at 70,7uV? In this case, the minimum usable output level will be proportional to S/0,024 (Vout=1,198V minimum usable if S is doubled). is this right?

Attached you can see my design for raise Slope and calibrate interception point. Please comment also.

Thanks for all,

Roger