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AD5686R/AD5685R/AD5684R

Question asked by E-Ninja on Jan 25, 2013
Latest reply on Jan 28, 2013 by E-Ninja

Hello,

 

I have just implemented AD5685R in a new design however when powering up the system the AD5685R circuit (TSSOP16) get very hot.

If I strip of everything surrounding the circuit except for connecting 5V to Vdd and pin 10 (GAIN) and 0V to GND I measure 4.2V on pin 11 (Vlogic). Idd is 1,8mA. With this configuration the circuit stays cool.

 

If I connect 5V to Vlogic and 0V to GND the voltage at pin 5 (Vdd) is zero.

 

With 5V at Vdd and 5V at Vlogic I measure Idd to 0.6mA; the circuit stays cool.

 

If I then lower the Vlogic voltage the Idd increase up to 40mA at Vlogic = 3.3V; the current at Vlogic I measure to 27mA.

 

I have also tried with two other AD5685R circuits and one AD5684R with the same behavior.

 

The datasheet specifies Vdd (2.7V to 5.5V) and Vlogic (1.8V to 5.5V); Ilogic max 3uA and Idd max 1.3mA.

 

Anyone know what's going on?

 

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