LTC2664 Maximum Output Voltage can not be reached?

Dear Sirs!

Currently I’m working on a LTC2664-16 DAC and I’m wondering why I cannot get the maximum output voltage out of the Part. The chip is integrated on a own Board (see SCH). When I try to get the maximum positive output Voltage out of a channel I would assume 10Volts as the datasheet shows. Of course Span and Reference should be configured correctly and headroom from the power supply has to be there.

I get very close to 10Volts but not exactly. On my design I get +9.9833 Volts positive and -9.9841 Volts negative. Where do I lose the 0,0167Volts / 0,0159Volts. There is no current down from the output, the load is a 100k resistor.

Due to the fact that I’m not sure if I made everything all right in my design, I tried trouble shooting the problem and bought the following Boards. Linduino ONE Board in combination with LT3471EDD for power supply (±12Volts) and the demo circuit 2376A-A. The same thing happened on this approach. I cannot get the ±10Volts at the output.

Can you give me some advice? Do I overlook something? Do I have a general mistake in my thoughts?

What else could I check? Any other ideas are welcome.