I am using an ADIS16209 for a low-power inclinometer. I have successfully interfaced to the device and can read data. However, the noise from the device is very high (5.5mg per sample as opposed to 1.7mg as stated in the datasheet). I use a low noise precision linear regulator (lt1461ais8) as a supply. Everything is populated on a 5x5cm PCB with short traces. The ADIS16209 is decoupled with a 1uF X7R capacitor. AVG_CNT is set to 0, and SMPL_PRD is the factory default.
I have noticed that the datasheet recommends a power supply ramp-up of less than 100us. My supply ramps up slower than this, but would this cause noise issues once the power rail has settled? The chip seems to work OK. The firmware revision of the chip is 1.5.
I have also tried resetting the chip once the power rail has stabilized, but that does not improve performance.
Could someone shed some light onto what might be the cause of this increased noise?