82551QM Datasheet, PDF (20/120 Pages) Intel Corporation – Fast Ethernet Multifunction PCI/CardBus Controller

82551QM — Networking Silicon
Table 9. PHY Signals
Symbol
Type
Name and Function
RBIAS100 B
RBIAS10
B
VREF
B
Reference Bias Resistor (100 Mbps). This pin should be connected
to a pull-down resistor.^a
Reference Bias Resistor (10 Mbps). This pin should be connected
to a pull-down resistor.^a
Voltage Reference. This pin is connected to a 1.25 V ± 1% external
voltage reference generator. To use the internal voltage reference
source, this pin should be left floating. Under normal circumstances,
the internal voltage reference should be used and this pin would be left
open.
a. Based on some board designs, RBIAS100 and RBIAS10 values may need to be increased/decreased to com-
pensate for high/low MDI transmit amplitude. See the 82562EZ(EX)/82551QM & 82540EM Combined Foot-
print LOM Design Guide for more information.
4.7
Power and Ground Signals
Table 10. Power and Ground Signals
Symbol
Type
Name and Function
VCC
DPS
VCCR
APS
VSSPL,
VSSPP,
DPS
VSSPT, VSS
NC
DPS
Digital 3.3 V Power. The VCC pins should be connected to the main
digital power supply. This is 3.3 V_AUX in systems with an auxiliary
power supply and PCI power in systems without an auxiliary power
supply. The power source is configured through the FLA1/AUXPWR
pin.
Analog Power. These pins should be connected directly to VCC.
Digital Ground. These pins should be connected to the main digital
ground plane.
No Connect. These pins should not be connected to any circuit. Pull-
up or pull-down resistors should not be used.
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Datasheet