Q:
Do the ADIS1620x/21x/22x products have any unique power supply requirements?
A:
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The ADIS1620x devices are complete digital sensor systems that provide calibrated tilt sensor outputs. The include a MEMS accelerometer, an analog front end and an embedded processor to support incline angle computation, application of correction formulas, filtering and the user interface. While these products don't present any unique requirements, which would not be risk items for other embedded processor systems, it may be helpful to refresh on some basic "best practices," through the use of reference design. Through all of our work in supporting our customers, we have found that the following attributes need consideration when developing a supply for these devices:
- Avoid passive elements that are in between controlled voltages and the VDD/GND pins on the ADIS1620x. They tend to elevate the dynamic source impedance, which creates more local noise that can cause problems.
- Leverage a regulator that provides a linear ramp for VDD, which moves its voltage from 0 to 3V in 100us or less. The ADP1712 is one example of a linear regulator that will support this.
- Manage ramp rates to avoid tripping over-current protection systems. The ADIS162xx devices all have > 2uFof capacitance across the VDD/GND pins.
- While the fast ramp rate will help manage this risk, be sensitive to noise sources. While there is not pass/fail criteria, one could use +/-10mV as a starting point for investigating potential problem spots.