
NOISE IMMUNITY
DECOUPLING CAPACITORS
• Know your performance response needs.
• Try to eliminate frequencies outside your performance needs
(i.e. filtering, smooth out spikes in DC power of IC’s).
• Digital Isolation Caps:
• Common practice is to isolate digital IC’s with isolation
capacitors. See manufacturer’s Spec Sheet for capacitor
values. Be sure to add to your schematic prior to Design
Review.
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STEP 6 HARNESSES
ANALYSIS HARNESS SIGNAL RESPONSE
Research you max data rate, distance, noise, parasitic
capacitance, reflections, distortion spec, etc.
Frequency Response for both: Digital rise time to support data
rate and if analog max frequency and distortion needs.
• DC to 100 khz Open Wire
• DC to 40 MB/s Ribbon Cable (less than 3’)
• SCSI, SPI-3 applications
• DC to 300 mhz Twisted Pair - unshielded, ribbon
• DC to 100/1000 MB/s ethernet Cat 5 minimum
spec. RJ45 connector.
• Coax, VHF 3000 megahz (scope probe, cable
TV) attenuation, reflectance, Cable TV, Rf
• DC to 4 gigahz Fiber Optics
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