1. Kit Description
The Si3406-non-isolated Flyback topology based evaluation board is a reference design for power supplies in Power over Ethernet
(PoE) Powered Device (PD) applications. The Si3406 device is described more completely in the data sheet and application notes. This
document describes the evaluation board.
The Si3406-non-ISO-FB-C3 EVB board is shown on the cover page. The schematic is shown in Figure 2.3 Si3406-Non-Isolated Fly-
back EVB Schematic: 5 V, Class 3 PD on page 4, and the layout is in 17. Board Layout. The dc output is at connectors J11(+) and
J12(–).
Boards are shipped configured to produce 5 V output voltage but can be configured for different output voltages, such as 3.3 or 12 V,
by changing resistor R14 and a few other components. Refer to “AN1130: Using the Si3406/Si34061/Si34062 PoE+ and Si3404 PoE
PD Controller in Isolated and Non-Isolated Designs” for more information. The preconfigured Class 3 signature can also be modified,
which is described as well in AN1130.
The Si3406 includes integrated diode bridge for both CT and SP connection. The integrated diode bridge can be used up to 200 mA
input current. Above 200 mA input current the external diode bridge is required.
The external diode bridge can be Schottky or silicon type.
The Si3406 device can operate with CT/SP pins open, in this configuration the external bridge should be Schottky type diode bridge.
To compensate the reverse leakage of the Schottky type diode bridges at high temperature, the recommended detection resistor should
be adjusted to the values listed in the following table:
Table 1.1. Recommended Detection Resistor Values
External Diode Bridge R
DET
Silicon Type 24.3 kΩ
Schottky Type 24.9 kΩ
UG332: Class 3 Non-Isolated Evaluation Board for the Si3406
Kit Description
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