I don't completely follow your description of the problem, but are you waiting for reset to go high before attempting a conversion?Sorry it is LTC2986 temperature sensor.
In the first phase of the start-up state all critical analog circuits are powered up. This includes the LDO, reference, charge pump and ADCs. During this first phase, the com- mand status register will be inaccessible to the user. This phase takes a maximum of 100ms to complete. Once this phase completes, the command status register will be accessible and return a value of 0x80 until the LTC2986 is completely initialized. Once the LTC2986 is initialized and ready to use, the INTERRUPT pin will go high and the command status register will return a read value of 0x40 (Start bit = 0, Done bit = 1). At this point the LTC2986 is fully initialized and is ready to perform a conversion