RPIXP2850BB Intel, RPIXP2850BB Datasheet - Page 68

• Manufacturer Part Number: RPIXP2850BB
• Manufacturer: Intel

Specifications of RPIXP2850BB

• Operating Supply Voltage (typ): 1.3/1.5/2.5/3.3V
• Operating Supply Voltage (max): 1.575/2.7/3.465V
• Operating Supply Voltage (min): 1.235/2.3/3.135V
• Mounting: Surface Mount
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Lead Free Status / Rohs Status: Not Compliant

IXP28XX Network Processor
QDR SRAM
Table 20.
4.5.3
Figure 30.
68
Table 20
QDR Address Stack-up Signal Cross-section Details
QDR SRAM D (Data Out) Topology
For Data Bus to work successfully at 233MHz only x9 SRAM parts need to be used and not x18
parts for multiple loads applications. Thus the data bus (READ and WRITE) should be split in two
halves each with a 9bit including the parity bit. The loads for each Data signal must be maintained
at 2 SRAMs only that are clam-shelled together so that they electrically constitute one load only.
As mentioned in section 3 on SRAM clam-shelling, some signals are not fully mirrored in the
SRAM part. Data-OUT is an example of these un-mirrored signals. Therefore, for Data-OUT
signals a daisy-chain configuration would be used for its topology. A better choice, however, is to
use a T-topology for Data-OUT whenever it is possible.
Figure 30
D (Data Out) Routing Topology
Table 21
Parameter
Data-Out (D0 - D7, D9 - D16)
Value
and Parity-Out (D8, D17)
Data-Out, Parity-Out
IXP2800 Driver
Daisy-Chained
lists the QDR address stack-up signal cross-section details.
provides routing guidelines for the QDR D signal group.
illustrates the routing topology for QDR SRAM D (Data Out).
Signals
Address
Intel
Signal
QDR
®
Trunk = 10
Width (W)
Branches
Trace
[mils]
Main
= 3.5
A
Thickness
(Tsignal)
R
Trace
[mils]
TT
0.5
= 50
V
TT
Ω
(S) [mils]
= 0.75V
Spacing
15 - 20
Trace
D
Thickness
[mils]
B
(TD1)
5.0
D1
Thickness
[mils]
(Td2)
5.7
D2
SRAM
Top
Hardware Design Guide
Er(D1) Er(D2)
3.5
C
3.8
Bottom
SRAM
B3954-01
between
Spacing
groups
20 - 25
signal
[mils]