ICM-30630
Page 14 of 18
Document Number: AN-000023
Revision: 1.1
4.
PCB DESIGN GUIDELINES
To achieve maximum ICM-30630 performance, the following recommendations should be followed during the board design
process:
4.1
EXTERNAL CRYSTAL
Keep any PCB traces between the crystal and the ICM-30630 (Pins 16 and 17), as short as possible. Although currents
running through the crystal oscillator are very small, any long lines will make it more sensitive to EMI, ESD and crosstalk.
Long lines also add parasitic capacitance and some series resistance to the oscillator, which could impact the start-up
characteristics of the oscillator. It is recommended to shield the crystal traces with ground traces, and keep other fast
switching clock/signal lines as far away from the crystal connections as possible. Placing a ground plane underneath the
crystal will reduce interference from other layers.
4.2
I
2
C AND SPI LINES
Keeping signal speeds, skews, and rise times in mind for high-speed digital bus, all I
2
C and SPI data and clock lines should
be length and impedance matched. Keep the bus traces as short as possible to reduce bus capacitance. Avoid routing
high-energy traces near digital bus lines.
4.3
POWER AND GND
Although the ICM-30630 is low-power component, wider power and ground PCB traces are very helpful to reduce
system noise. It is recommended to design power and ground traces for PCBs with a least an 8 mil width in mind. Avoid
split ground and power planes, as they act as antennas and can radiate with detrimental effects on fast bus and/or
sensitive signals.
4.4
MEMS COMPONENT PLACEMENT
The gyroscope and accelerometer inside the ICM-30630 are MEMS-based designs, making the ICM-30630 placement
sensitive to mechanical strength. Placing MEMS sensors in areas where the board flexes puts unnecessary mechanical
stress on the MEMS sensor package, which leads to the possibility of higher offsets and damage to the sensor. For
details on proper sensor placement, please refer to InvenSense’s application notes
MEMS Motion Handling and
Assembly Guide
,
Accelerometer and Gyroscope Design Guidelines
and
Compass Design Guidelines
.
