LTC2983 problems with interrupt/SDO

Anonymous
Anonymous

I have a test circuit with the LTC2983CLX. The circuit is build as  in the datasheet (Caps are placed as in the datasheet).

Grounds and VDD pins all are connected and supplied.

What I have measured: VDD=5,2V, LDO pin is at 2,5V. Reset input is at 5,2V. The Scope shows stable voltages with a ripple of about 100mV.

 

BUT:

- Interrupt output stays at 0,75V (tried with no load and 2k2 pulled to ground) - SDO seems to be in High impedance state.

I don't know where else to look at...

 

I have two chips and both have the same behaviour...

Regards

Thomas