am79c960 Advanced Micro Devices, am79c960 Datasheet - Page 29

• Manufacturer Part Number: am79c960
• Description: Pcnettm-isa Single-chip Ethernet Controller
• Manufacturer: Advanced Micro Devices

PIN DESCRIPTION: POWER SUPPLIES
All power pins with a “D” prefix are digital pins connected
to the digital circuitry and digital I/O buffers. All power
pins with an “A” prefix are analog power pins connected
to the analog circuitry. Not all analog pins are quiet and
special precaution must be taken when doing board lay-
out. Some analog pins are more noisy than others and
must be separated from the other analog pins.
AVDD1–4
Analog Power (4 Pins)
Supplies power to analog portions of the PCnet-ISA
controller.
printed circuit board layout to avoid excessive noise on
these lines. These supply lines should be kept separate
from the DVDD supply pins and as far back to the power
supply as is practically possible. AVDD3 is an exception
and should be connected to DVDD supply and away
from remaining AVDD supply pins. See the table below
for more details.
AVSS1–2
Analog Ground (2 Pins)
Supplies
PCnet-ISA controller. Special attention should be paid
Analog
Power
AVDD2
AVDD4
AVDD1
AVDD3
and
ground reference to analog portions of
Special attention should be paid to the
AVSS2
AVSS1
Ground
Analog
Analog Power Pins and the Circuits to Which They are Connected
These pins are connected to the analog
voltage reference circuit and VCO.
These pins are connected to analog
circuits such as AUI and Twisted Pair
receive logic.
These pins are connected to the AUI and
Twisted Pair drivers.
Power
Power
Circuit
P R E L I M I N A R Y
Am79C960
to the printed circuit board layout to avoid excessive
noise on these lines. These supply lines should be kept
separate from the DVSS ground pins and as far back to
the power supply as is practically possible. AVSS1 is an
exception and should be connected to DVSS supply and
away from remaining AVSS supply pins. See the table
below for more details.
DVDD1–6
Digital Power (6 Pins)
Supplies power to digital portions of PCnet-ISA control-
ler. Four pins are used by Input/Output buffer drivers
and two are used by the internal digital circuitry.
DVSS1–12
Digital Ground (12 Pins)
Supplies
PCnet-ISA controller. Ten pins are used by Input/Output
buffer drivers and two are used by the internal digital
circuitry.
These pins should be kept quiet. They
should be kept separated with low- and
high-frequency by-pass capacitors.
These pins are moderately quiet and
should be connected to the VDD supply
a short distance away from the DVDD pins.
These pins are more noisy and should be
connected to the DVDD/DVSS supplies.
ground
reference to digital portions of
Comments
Power
Power
AMD
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