Texas Instruments TIDA-010046, Design Manual

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TIDA-010046
PD Side Board
Clock Source Status LEDs
MSP430
Pin Headers
(MAC)
DP83825
10/100MBPS
ETH PHY
Internal Loop-Back
External Loop-
Back
DP83825
10/100MBPS
ETH PHY
DP83822
10/100MBPS
ETH PHY
RMII
RMII
TIDA-010046
PSE Side Board
Ethernet
Cable
R
J
4
5
x
x
x
x
x
MSP430
x
x
x
x
x
Power + Data Out
ESD
Diode
Array
ESD
Diode
Array
ESD
Diode
Array
ESD
Diode
Array
TVS
Diode
Array
TVS
Diode
Array
R
J
4
5
ESD
Diode
Array
ESD
Diode
Array
Clock Source Status LEDs Status LEDs
TPS23861
PSE
TPS7A4001 LDO
(48 V to 3.3 V)
LP5907 LDO
(5 V to 3.3 V)
LP5907 LDO
(5 V to 3.3 V)
TPS7A26 LDO
(12 V to 3.3 V)
TPS2121
Power MUX
Isolation
Barrier Isolation
Barrier
Isolation Barrier
PRBS ON
48 V RTN
TVS
Diode
Array
MDC
MDIO
MDIO
MDC
0 … F
5 V
LM5160
Iso. Fly- %XFNŒ
(12 V to 3.6 V)
+12V_IN
LM3478
Boost DC/DC
(12 V to 48 V)
+48V
TVS
Diode
Array
TVS
Diode
Array
+48 V
TVS
Diode
Array
RTN
Power
R
J
4
5
TPS23755
Powered Device (PD) with
Integrated DC/DC
12 V_PoE +12V_IN
+12V_OUT
3.3 V for ETH PHY & MSP
MDIO
MDC
3.3 V
for
MSP430
3.3 V
for ETH
PHYs
USB
USB
PRBS ON
Write 0x7100 in Register 0x0016
Internal Loopback
Write 0x0110 in register 0x0016
Hardware, Software, Testing Requirements, and Test Results
www.ti.com
36 TIDUES1A – October 2019 – Revised February 2020
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Copyright © 2019–2020, Texas Instruments Incorporated
EMC Compliant 10/100-Mbps Ethernet PHY Reference Design With IEEE
802.3at Type-1 (
≤ 12.95 W) PoE-PD
Figure 35 shows the DUT configuration for radiated emission testing. The DUT (PD side board) was placed on the nonconductive table inside the
chamber, whereas the PSE side board was kept outside the chamber connected through a long CAT5e cable. The CAT5e cable was externally
shielded just to debug or focus on the radiated emissions coming through the DUT rather than radiated emission coming from cable itself. The
PSE side board was powered by a 12-V lead-acid battery. The PD side board was powered from PoE, which means the DC/DC power supply on
the DUT was ON. The DP83825I Ethernet PHY on PSE side board was configured to generate pseudo-random binary sequence (PRBS), while
the DP83825I Ethernet PHY on PD side board was configured to internally loopback the PRBS packets. Therefore, the radiated emission testing
was performed when the DUT is continuously communicating with the PSE side board (link partner). Disturbance field strength limits (peak)
according to CISPR 22 (EN 55022) and FCC Part 15 Subpart B, normalized to a distance of 3 m.
Figure 36 shows the radiated emission plot with
both horizontal and vertical polarizations in a single graph.
Figure 35. DUT Configuration for Radiated Emission Testing