AN2344 Freescale Semiconductor / Motorola, AN2344 Datasheet - Page 8

• Manufacturer Part Number: AN2344
• Description: HC908EY16 EMI Radiated Emission Results
• Manufacturer: Freescale Semiconductor / Motorola

AN2344/D
Analysis/Conclusions
References
Further Reading
8
The results obtained from the radiated emissions testing are shown in
Appendix A. They demonstrate that the radiated emissions from the
HC908EY16 microcontroller are very low at a device level. They also confirm
that there is a noticeable difference in the emissions spectrum between the
external crystal and ICG configurations, with the ICG generally showing a lower
emissions spectrum. Therefore, the use of the internal clock generation module
is recommended in applications where radiated emissions are regarded as a
potential problem. There is an additional advantage in using the ICG
configuration in low cost applications as there is no requirement for the external
crystal components and therefore there will be a related cost saving.
While the analysis proves that the HC908EY16 exhibits good radiated
emissions characteristics, it is important to realise that device level data does
not always give an accurate representation of the emissions that will be
obtained in a real life application. Board and module level emissions
measurements are very dependant on the board layout, the components used
and other circuitry. Therefore each application has to be tested in order to fully
understand the emissions measurements.
The following EMC related application notes can be downloaded from
http://e-www.motorola.com/webapp/sps/library/docu_lib.jsp
AN1263/D: System Design and Layout Techniques for Noise Reduction in
MCU-Based Systems
AN1705/D: Noise Reduction Techniques for Microcontroller Based Systems
AN2321/D: Designing for Board Level Electromagnetic Compatibility
1. 1 MC68HC908EY16/D Rev 2.0. This specification is available on the
2. 2 Electromagnetic Compatibility Qualification and Analysis of
Freescale Semiconductor, Inc.
HC908EY16 EMI Radiated Emissions Results
For More Information On This Product,
Motorola Semiconductor Products webpage at
sps.com/products/index.html.
Microcontrollers (100 kHz – 1 GHz) Test Methods and Procedures.
Go to: www.freescale.com
http://mot-
MOTOROLA