At power-up, my LTC2668 initializes all channels to 0V. That's correct by my setting of MSP0 = 5V, MSP1 = 5V and MSP2 = 0. According to Table 4, that selects 0-10V operation with initial outputs at 0V. This condition persists for maybe several seconds, then the DAC switches to driving 5V at all outputs. CS#/LD is pulled up to OVP, but the other SPI pins are floating. CLR# is also tied to OVP. The power supplies are steady at the time the output voltages change.
Is there any chance the DAC could be changing this on its own in response to a problem? Thanks.