UG425: Si3474 EVB User's Guide
Si3474 Quad 90 W Ethernet Port EVB
The Si3474 is suitable for use in either a four-port 802.3bt PSE, eight-port 802.at PSE,
or a mix of 802.3bt and 802.3at ports. The Si3474 achieves this by having two separate
quads each powering four 2-pair ports. Each quad can either be configured for two
802.3bt 4-pair ports of for four 802.3at 2-pair ports. The Si3474-EVB includes an RJ45
interface board called the POE_BT_CB to allow evaluation of the Si3474 in a mixed
802.3bt and 802.3at system.
The Si3474-EVB can power up PDs without any software installation needed. The
Si3474-EVB can be jumper-selected (J8) to automatically configure the Si3474 Port
Power Allocation. Note that when using the Si3474 in AUTO mode, the ports must either
all be in 802.3bt mode or 802.3at mode. To use the Si3474 in a mixed system, it will be
necessary to access the Si3474 registers through I
2
C. The Si3474-EVB allows access
to the Si3474 registers through a Silicon Labs CP2112 USB to I
2
C bridge. A Python in-
terface is provided to allow evaluation through Windows PC, Linux or MacOS comput-
ers.
KEY FEATURES
• IEEE 802.3bt compliant
• Up to Four 802.3bt Ports or Eight 802.3at
Ports
• AUTO Mode Jumpers
• No software needed for basic operation
• Configurable Max Port Power
• Available Direct I
2
C Access to Si3474
Registers
• USB Interface using Silicon Labs
CP2112 USB to I
2
C Bridge
• Python interface to Windows, Linux or
MacOS
Parameter
Condition
Specifications
PSE Input Voltage Range
Connector J4
52 to 57 V
PoE Type/Class
Type 4, Class 8
IEEE 802.3bt
Daughtercard Size
2.5 x 2.5 inches, 61 x 61 mm
Baseboard Size
3 x 5.35 inches, 76 x 136 mm
EVB Height
Does not include headers
1.2 inch, 30 mm
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