there is a 1.6V output when in+ is floating and in- is grounded

Question

hello: 
 i use an ada4940-1 to build a test circuit(as follows).i use the chip to convert a single-ended signal to differential.i found that there is a 1.6V output between out+ and out- when in+ is floating.i try to add R4(100K),and i found the output is 1.4V? 
 annd more,i use a desktop power source to provide the intput voltage,i found the current of the source is negative! 
 did i make a wrong use of the chip?

Gauzz · Accepted Answer

Hi, 
 We would not advise the input to be left floating when the device is supplied or powered, during these conditions the part is non-linear and the output as you are seeing may behave differently. Try grounding both inputs first to see if the part is still functional. And adjust your Vocm to midsupply or leave it floating. Vocm is internally midsupply biased. Regards, Goz)

Partner Forums

Partner Libraries

Products Mentioned

there is a 1.6V output when in+ is floating and in- is grounded