450NX Datasheet, PDF (129/248 Pages) Intel Corporation – Intel 450NX PCIset

12.1.4 LDSTB# Usage
12.1 Signal Specifications
xxQData
LDSTB#
LRD#
HCLKIN
Latch
DQ
EN
DFlop
DQ
Enabled
DFlop
DQ
EN
To Core
Figure 12-2: LDSTB# Usage
LDSTB# opens a flow-through latch to enable fine tuning of the read data timing. By adjusting
the trace length of the LDSTB# signal it is possible to match the CAS# or RAS# timings
(whichever is last) for optimal timing margin on DRAM read cycles.
12.1.5 VCCA Pins
The VCCA inputs provide the analog supply voltage used by the internal PLLs. To ensure
PLL stability, a filter circuit must be used from the board VCC. Figure 12-3 shows a
recommended circuit. It is important to note that a separate filter for each VCCA pin is
necessary to avoid feeding noise from one analog circuit to another.
VCC
10 Ohm 1%
10uF
VCCA
Figure 12-3: VCCA filter
Intel® 450NX PCIset
12-5