VSC8641XKO Vitesse Semiconductor Corp, VSC8641XKO Datasheet - Page 26

• Manufacturer Part Number: VSC8641XKO
• Description: IC PHY 10/100/1000 100-LQFP
• Manufacturer: Vitesse Semiconductor Corp
• Type: PHY Transceiverr

Specifications of VSC8641XKO

• Number Of Drivers/receivers: 1/1
• Protocol: Gigabit Ethernet
• Voltage - Supply: 2.5V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 100-LQFP
• Case: TQFP
• Dc: 07+
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 907-1031

Figure 7.
Revision 4.3
August 2009
The VSC8641 device is compatible with switch designs that are intended for use in
systems that supply power to Data Terminal Equipment (DTE) using the MDI or twisted
pair cable, as described in clause 33 of the IEEE standard 802.3af. The following
illustration shows an example of this type of application.
Inline Powered Ethernet Switch Diagram
The following procedure describes the process that an Ethernet switch must perform to
process inline power requests made by a link partner (LP) that is, in turn, capable of
receiving inline power:
1. Enable the inline powered device detection mode on each VSC8641 PHY using its
2. Ensure that the VSC8641 device auto-negotiation enable bit (register 0.12) is also
3. The VSC8641 PHY monitors its inputs for the FLP signal looped back by the LP. An
Interface
RGMII
Cat5
serial management interface. Set register bit 23E.10 to 1.
set to 1. In the application, the device sends a special Fast Link Pulse (FLP) signal
to the LP. Reading register bit 23E.9:8 returns 00 during the search for devices that
require Power-over-Ethernet (PoE).
LP capable of receiving PoE will loopback the FLP pulses when it is in a powered-
down state. This is reported when VSC8641 device register bit 23E.9:8 reads back
01. It can also be verified as an inline power detection interrupt by reading
VSC8641 device register bit 26.9, which should be a 1, and which is subsequently
PHY_0
X-former
RJ-45
I/F
PHY_1
X-former
Gigabit Switch
RJ-45
I/F
SMI
PHY_n
X-former
RJ-45
I/F
Functional Descriptions
VSC8641 Datasheet
Processor
Supply Unit
Power
Inline
Page 26
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