Design Guide
79
Memory Interface Routing Guidelines
6.8
Miscellaneous Signals
The MCH uses a compensation signal to adjust buffer characteristics and output voltage swing over
temperature, process, and voltage skew. Calibration is done periodically by sampling the
DDRCOMP, DDRCVOH, and DDRCVOL pins on the MCH. Connect DDRCOMP to the DDR
termination voltage (1.25 V) through a 6.81
Ω
± 1% resistor as illustrated in
the resistor within 1 in. of the MCH. Likewise, keep the voltage divider networks within 1 in. of the
MCH (see
Figure 6-14. DDRCOMP Resistive Compensation
MCH
DDR VTERM
(1.25 V)
6.81
Ω ±
1%
<1"
DDRCOMP
Figure 6-15. DDRCVOL and DDRCVOH Resistive Compensation
MCH
DDRCVOH
DDRCVOL
DDR VDD
(2.5V)
DDR VTERM
(1.25V)
< 1"
DDR VTERM
(1.25V)
0.01 µF
< 1"
MCH
7 k
Ω
± 1%
13 k
Ω
±
1%
13 k
Ω
± 1%
7 k
Ω
±
1%
0.01 µF
0.01 µF
0.01 µF
Summary of Contents for Xeon
Page 24: ...Introduction 24 Design Guide This page is intentionally left blank ...
Page 30: ...Component Quadrant Layout 30 Design Guide This page is intentionally left blank ...
Page 52: ...Platform Clock Routing Guidelines 52 Design Guide This page is intentionally left blank ...
Page 66: ...System Bus Routing Guidelines 66 Design Guide This page is intentionally left blank ...
Page 118: ...Intel 82870P2 P64H2 118 Design Guide This page is intentionally left blank ...
Page 146: ...I O Controller Hub 146 Design Guide This page is intentionally left blank ...
Page 148: ...Debug Port 148 Design Guide This page is intentionally left blank ...
Page 210: ...Schematic Checklist 210 Design Guide This page is intentionally left blank ...
Page 220: ...Layout Checklist 220 Design Guide This page is intentionally left blank ...
Page 222: ...Schematics 222 Design Guide This page is intentionally left blank ...