Kontron COMe Starterkit Eval T2 - Manual (Page 192)

Carrier Board PCB Layout Guidelines
6.6.2. IDE Trace Routing Guidelines
Table 70: IDE Trace Routing Guidelines
Parameter Trace Routing
Maximum Transfer Rate @ ATA100 100 MB/sec
Maximum length allowance for signals on the COM Express
Carrier Board @ ATA100. 7.0 inches
Single-ended Impedance 55 Ω +/-15%
Trace width (W) PCB stack-up dependent
Spacing between signals (inter-signal) (S) PCB stack-up dependent
Length matching between strobe and data signals Max. 450mils
Length matching between data signals Max. 200mils
Length matching between strobe signals 'IDE_IOR' and
'IDE_IOW'. Max. 100mils
Spacing from edge of plane Min. 40mils
Reference plane GND referenced preferred
Via Usage Try to minimize number of vias
PICMG ® COM Express ® Carrier Board Design Guide Rev. 2.0 / December 6, 2013
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