Texas Instruments BOOST-PSEMTHR-007, Руководство пользователя, Страница: 3 / 38

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3 SLVUBP0A – May 2019 – Revised August 2019
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TPS23881EVM: PoE, PSE, TPS23881 Evaluation Module
The minimum PSE port voltage is 44 VDC for type 1, 50 V for type 2 and type 3, and 52 V for type 4.
During evaluation, choose the appropriate DC power supply for different environments.
2.1.2 Local 3.3 V (Labeled 3.3 V)
Local 3.3 V for local devices (labeled as 3.3 V) is provided by the onboard LM5019 buck converter. The
LM5019 provides a basic power-on sequence and provides a well-controlled and consistent start-up. In
addition to 54 V, the TPS23881 requires 3.3 V for the digital circuitry and this is routed up to
TPS23881EVM-008 over the connector interface. The current consumption is 6-mA typical and 12-mA
maximum.
2.1.3 External 3.3 V (Labeled 3.3 V_USB)
The BOOST-PSEMTHR-007 provides galvanic isolation between the PoE power side and host side using
digital isolators (ISO7241CD). The host side power is provided either from J2 (from
USB2ANY ) or J5 (from
MSP-EXP430FR5969 ).
CAUTION
Do not use USB2ANY and LaunchPad simultaneously.
Table 1. TPS23881EVM Voltage Rail Current Requirements
VOLTAGE RAIL TYPICAL (mA) MAXIMUM (mA)
3.3 V_USB 2.5 3
3.3 V 6 12
VPWR (Miscellaneous) 35 57
VPWR (4 × 2 Pair Ports and 2 × 4 pair Ports) 5556 5578
VPWR Total (4 × 2 Pair Ports and 2 × 4 pair Ports) 5591 5613
2.2 PoE Port Interfaces
The TPS23881 device must be configured through the host to become operational. This EVM provides
two ways to control the TPS23881: TPS238x EVM GUI (with
USB2ANY ) and MSP-EXP430FR5969
LaunchPad.
2.2.1 IEEE802.3bt 2-Pair Ports
Four 2-pair ports are provided at J19, J20, J8, and J7 for 2-pair ports 1, 2, 3, and 4, respectively. The
power furnished is according to alternative A with MDI-X polarity.
2.2.2 IEEE802.3bt 4-Pair Ports
Two 4-pair high power ports are provided at J21 and J9 for 4-pair ports 1 and 2, respectively. The power
furnished is according to alternative A with MDI-X polarity and alternative B with S polarity on a single port
connector. A single- or dual-signature PD may be powered by the 4-pair ports with proper port
configuration (enabling 4-pair mode).
2.3 I
2
C Interfaces
Two I
2
C interfaces to the TPS23881 are provided on the EVM.
2.3.1 USB2ANY
J2 provides an interface with the USB2ANY adapter when using a PC and GUI.