cn8237 Mindspeed Technologies, cn8237 Datasheet - Page 362

• Manufacturer Part Number: cn8237
• Description: Atm Oc-12 Servicesar Plus With Xbr Traffic Management
• Manufacturer: Mindspeed Technologies

16.0 Electrical and Mechanical Specifications
16.1 Timing
Figure 16-13. Recommended PCB Layout
16-14
NOTE(S):
1. Place series terminators as close to SAR BGA package as possible.
2. Place SSRAMs as close as possible to series terminators.
3. Dashed lines represent additional SSRAMs on the backside of the PCB.
GOAL:
To keep
this
distance
to an
absolute
minimum.
The most important point is to keep all PCB traces to a minimum and of
equivalent length. Following a careful timing analysis and careful board layout
keeps the design within all minimum and maximum design parameters.
SSRAM chips should be used. This allows PCB trace routing to be similar to that
of the by_16 SSRAM devices and also keeps the capacitive loading the same.
A daisy chain routing approach may be more practical for some PCB designs.
If the application requires more than two banks of memory, then by_36
SSRAM
Mindspeed Technologies
RSM Local Memory
Interface Pins
SAR
SSRAM
ATM OC-12 ServiceSAR Plus with xBR Traffic Management
SEG
Local
Memory
Interface
Pins
GOAL: To keep this distance
to an absolute minimum.
Series Terminators
™
SSRAM
SSRAM
Topside of PCB
28237-DSH-001-C
8237_165
CN8237