Linear Technology DC2475A-A Quick setup guide

1
dc2475aafb
DEMO MANUAL
DC2475A-A
Description
LT4295, LT4321
High Efficiency IEEE802.3bt (PoE++, Type 3,
40W) PD with PoE Ideal Diode Bridge
Demonstrationcircuit2475A-AisanIEEE802.3bt (Draft2.0)
compliant Power over Ethernet (PoE) powered device(PD).
It features the LT
®
4295 PD interface and switching regulator
controller with the LT4321 PoE ideal diode bridge controller.
The LT4295 provides IEEE802.3af (PoE, Type 1),
IEEE802.3at (PoE+, Type 2), and IEEE802.3bt (PoE++,
Type 3 and 4) compliant interfacing and power supply
control. It utilizes an external, low RDS(ON) (57mΩ typi-
cal) N-channel FET for the Hot Swap function to improve
efficiency. The LT4295 controls a DC/DC converter that
utilizes a highly efficient flyback topology with synchro-
nous rectification.
The LT4321 controls eight low RDS(ON) (57mΩ typical)
N-channel FETs to further improve end-to-end power
L, LT, LTC, LTM, Linear Technology, the Linear logo and LTPoE++ are registered trademarks of
Analog Devices, Inc. All other trademarks are the property of their respective owners.
performance summary
BoarD photo
delivery efficiency and ease thermal design. This solution
replaces the eight diodes typically found in a passive PoE
rectifier bridge.
The DC2475A-A accepts up to 40W of delivered power
from a power sourcing equipment (PSE) via the RJ45
connector (J1) or a local 48VDC power supply using the
auxiliary supply input. When both supplies are connected,
the auxiliary supply input has priority over the PoE input.
The DC2475A-A supplies a 12V output at up to 3A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2475A-A
Top Side
PARAMETER CONDITIONS VALUE
Port Voltage (VPORT) At RJ45 37V to 57V
Auxiliary Voltage From AUX+to AUX–Terminals 37V to 57V
Output Voltage (VOUT) 12V (Typical)
Output Current (IOUT) 3A (Max)
Output Voltage Ripple VPORT = 44V, IOUT = 3A 85mVP-P (Typical)
Load Regulation ±0.1% (Typical)
Efficiency VPORT = 50V, IOUT = 3A, End-to-End 92% (Typical)
Switching Frequency 250kHz (Typical)
Bottom Side

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dc2475aafb
DEMO MANUAL
DC2475A-A
typicaL performance characteristics
Top Side Bottom Side
Figure 1. Thermal Pictures (Conditions: VPORT = 44V, VOUT = 12V, IOUT = 3A)
Figure 2. Efficiency (End-to-End)
LOAD CURRENT (A)
0
0.5
1
1.5
2
2.5
3
0
10
20
30
40
50
60
70
80
90
100
EFFICIENCY (%)
DC2475AA F02
44V
50V
57V
VPORT
Figure 3. Load Regulation
LOAD CURRENT (A)
0
0.5
1
1.5
2
2.5
3
11.80
11.85
11.90
11.95
12.00
12.05
12.10
12.15
12.20
VOUT (V)
DC2475AA F03
44V
50V
57V
VPORT

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dc2475aafb
DEMO MANUAL
DC2475A-A
Figure 4. Switch Node Waveforms (Conditions: VPORT = 57V, VOUT = 12V, IOUT = 3A)
Figure 5. Output Voltage Ripple (Conditions: VPORT = 44V, VOUT = 12V, IOUT = 3A)
typicaL performance characteristics

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dc2475aafb
DEMO MANUAL
DC2475A-A
Figure 6. Load Transient Response (Conditions: VPORT = 44V, Load Step: 1.5A to 3A to 1.5A)
Figure 7. Gain and Phase Margin of the Flyback DC/DC Converter (Conditions: VPORT = 44V, VOUT = 12V, IOUT = 3A)
typicaL performance characteristics
CROSSOVER FREQUENCY (kHz) GAIN MARGIN (dB) PHASE MARGIN (deg)
5 20 64

5
dc2475aafb
DEMO MANUAL
DC2475A-A
QuicK start proceDure
Power over Ethernet (PoE) Input
1. Disconnect auxiliary supply if it is connected to AUX+
and AUX– inputs of the DC2475A-A.
2. Place and connect test equipment (voltmeter, ammeter,
oscilloscope, and electronic load) as shown in Figure8.
3. Turn down the electronic load to a minimum value and
turn off the electronic load.
4. Connect the output of the IEEE 802.3bt compliant PSE
to the RJ45 connector (J1) of the DC2475A using a
CAT5e or CAT6 Ethernet cable. (See note.)
5. After the LED (D4) on the DC2475A is lit, check the
output voltage using a voltmeter. Output voltage should
be within 12.0V ± 0.2V.
Figure 8. Setup Diagram for PoE Input
6. Turn on the electronic load and increase its load cur-
rent up to 3A. Observe the output voltage regulation,
efficiency, and other parameters.
7. Verify T2P response with an oscilloscope as shown in
Figure 8. The T2P response to the type of PSE connected
to the DC2475A-A is provided in Table 1.
Note:An 802.3bt PSE has not yet been released. In
the interim, an LTPoE++
®
compliant PSE (DC1814A-B)
may be used to provide power to the DC2475A-A. The
LTPoE++ classificationwillnotbe802.3bt compliant, but
the PSE will provide a compatible detection and power
output. Specifically, the T2P output of the DC2475A-A
is different from the behavior stated in Table 1 and will
indicate connection to a Type 2 PSE. Otherwise PD
behavior will be unaffected.
Table 1. T2P Response vs PSE Type
PSE T2P RESPONSE NEGOTIATED PD INPUT POWER
IEEE
Logic High 13W
Logic Low 25.5W
50% Logic High/50% Logic Low, Toggle at 976Hz ±7% 40W
LTPoE++, 52.7W Logic Low 40W
IEEE 802.3bt
PSE
+
–
DC POWER
SUPPLY
+
–
AMMETER
+
–
VOLTMETER
+
–
ELECTRONIC
LOAD
+
–
OSCILLOSCOPE
+
–
CAT5e
OR CAT6
CABLE
J1

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dc2475aafb
DEMO MANUAL
DC2475A-A
Figure 9: Setup Diagram for Auxiliary Supply Input
Auxiliary Supply Input
1. Place and connect test equipment (voltmeter, ammeter,
oscilloscope, and electronic load) as shown in Figure9.
2. Turn down the electronic load to a minimum value and
turn off the electronic load.
3. Connect the output of the auxiliary supply to the
DC2475A as shown in Figure 9. Turn on the auxiliary
supply and set its current limit to 2A. Then increase its
output voltage to 48V.
QuicK start proceDure
4. Once the LED (D4) on the DC2475A is lit, check the
output voltage using a voltmeter. Output voltage should
be within 12.0V ± 0.2V.
5. Turn on the electronic load and increase its load cur-
rent up to 3A. Observe the output voltage regulation,
efficiency, and other parameters.
6. Verify T2P response with an oscilloscope as shown
in Figure 9. The T2P response during auxiliary power
operation is provided in Table 2.
Table 2. T2P Response During Auxiliary Power Operation
T2P RESPONSE PD OUTPUT POWER (W)
75% Logic High/25% Logic Low, Toggle at 976Hz ±7% 36
AMMETER
+
–
VOLTMETER
+
–
ELECTRONIC
LOAD
+
–
OSCILLOSCOPE
+
–
J1
AUXILIARY SUPPLY
+–

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dc2475aafb
DEMO MANUAL
DC2475A-A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
DC2475A General BOM
1 1 CG1 CAP, CER, X7R 1000pF 2kV 10% 1808 MURATA GR442QR73D102KW01L
2 1 CG2 CAP, CER, X7R 0.01µF 100V 20% 1206 AVX 12061C103MAT2A
3 0 C1 CAP, CER, OPT 2kV 1812 OPT
4 0 C5 CAP, CER, X7U OPT 6.3V 10% 1210 OPT
5 1 C6 CAP, ELEC, 10µF 100V 10% 6.3x7.7 SUNCON 100CE10BS
6 1 C7 CAP, CER, X7R 2.2µF 100V 10% 1210 MURATA GRM32ER72A225KA35
7 1 C10 CAP, CER, X7R 10nF 100V 20% 0603 MURATA GRM188R72A103KA01D
8 1 C11 CAP, CER, X7R 0.047µF 100V 20% 0603 KEMET C0603C473M1RACTU
9 1 C12 CAP, CER, X7R 0.047µF 100V 10% 0805 MURATA GRM21BR72A473KA01L
10 1 C13 CAP, CER, X7R 10µF 10V 10% 1206 MURATA GRM31CR71A106KA01L
11 0 C15, C18, C19, C21 CAP, CER, X5R OPT 2kV 20% 1812 OPT
12 1 C17 CAP, CER, X7R 1µF 25V 10% 0603 MURATA GRM188R71E105KA12
13 1 C20 CAP, CER, X7R 2.2nF 25V 10% 0603 MURATA GRM188R71E222KA01
14 1 C23 CAP, CER, X7R 4.7nF 2kV 1812 MURATA GR443DR73D472KW01L
15 1 C26 CAP, CER, X7R 100pF 16V 0402 AVX, 0402YC101KAT2A
16 0 C27 CAP, CER, X7R OPT 6.3V 10% 0402 OPT
17 1 D1 DIODE, SCHOTTKY, B2100 100V SMB DIODES INC B2100-13-F
18 1 D2 DIODE, TVS, PTVS58VS1UR 58V SOD123 NXP PTVS58VS1UR
19 1 D3 DIODE, ZENER, MMSZ5252BS 24V SOD323 DIODES INC MMSZ5252BS
20 1 D4 DIODE, LED GREEN ROHM SML-010FTT86L
21 1 D13 DIODE, SCHOTTKY, NXP, BAT46W 100V SOD323 NXP BAT46WJ,115
22 1 D15 DIODE, DIODE INC, BAV19WS 120V SOD323 DIODE INC BAV19WS
23 1 D16 DIODE, TVS, PTVS58VS1UR 58V SOD123 NXP PTVS58VS1UR
24 1 D17 DIODE, SCHOTTKY, PMEG1020EA 10V SOD323 NXP PMEG1020EA
25 1 D19 DIODE, TVS, PTVS58VS1UR 58V SOD123 NXP PTVS58VS1UR
26 7 E1, E2, E3, E4, E9, E10,
E12
TP, TURRET, PAD150-094 0.094" MILL-MAX 2501-2-00-80-00-00-07-0
27 1 J1 CONN, INTEGRATED JACK, 7499511001 WURTH 7499511001A
28 1 J2 CONN, RJ45 JACK, SS-6488-NF-K1 STEWART CONNECTOR SS-6488-NF-K1
ALTERNATE SS-6488S-A-NF
29 1 L2 IND, 10µH COILCRAFT DO1608C-103
30 1 L4 IND, 100µH COILCRAFT DO1608C-104

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dc2475aafb
DEMO MANUAL
DC2475A-A
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
31 9 Q1, Q11, Q12, Q13,
Q14, Q15, Q16, Q17,
Q18
MOSFET, N-CH, PSMN075-100MSE 100V LFPAK33 NXP PSMN075-100MSE
32 1 Q5 TRANSISTOR, PNP, MMBT3906 40V SOT23 FAIRCHILD MMBT3906
33 1 Q6 TRANSISTOR, NPN, MMBT3904 40V SOT23 FAIRCHILD MMBT3904
34 1 Q7 TRAN, PNP, FMMT723 100V SOT23 DIODES INC FMMT723TA
35 0 Q7 (ALTERNATE) TRAN, PNP, PBSS9110T 100V SOT23 NXP PBSS9110T
36 4 RT1, RT2, RT3, RT4 RES, CHIP, 75Ω 5% 0603 NIC NRC06J750TRF
37 1 R5 RES, CHIP, 8.2Ω 5% 0805 NIC NRC10J8R2TRF
38 1 R6 RES, CHIP, 3.3k 5% 0603 NIC NRC06J332TRF
39 1 R7 RES, CHIP, 20Ω 5% 0805 VISHAY CRCW080520R0JNEA
40 1 R12 RES, CHIP, 0Ω 5% 0603 NIC NRC06ZOTRF
41 1 R13 RES, CHIP, 100Ω 5% 0603 VISHAY CRCW0603100RFKEA
42 1 R15 RES, CHIP, 15Ω 5% 0603 NIC NRC06J150TRF
43 1 R17 RES, CHIP, 2.00k 1% 0603 NIC NRC06F2001TRF
44 1 R18 RES, CHIP, 10k 5% 0603 YAGEO RC0603JR-0710KL
45 1 R21 RES, CHIP, 174k 1% 0603 VISHAY CRCW0603174KFKEA
46 1 R22 RES, CHIP, 107k 1% 0603 NIC NRC06F1073TRF
47 1 R27 RES, CHIP, 0Ω 5% 0402 NIC NRC04ZOTRF
48 1 R28 RES, CHIP, 0Ω 5% 0603 NIC NRC06ZOTRF
49 1 R29 RES, CHIP, 52.3k 1% 0603 VISHAY CRCW060352K3FKEA
50 0 R32 RES, CHIP, OPT 5% 1812 OPT
51 1 T3 XFMR, SMD GATE DRIVE, PE-68386NL PULSE PE-68386NL
52 0 T3 (ALTERNATE) XFMR, SMD GATE DRIVE, EPA4271GE PCA EPA4271GE
53 1 U3 IC, PoE IDEAL BRIDGE CONTROLLER, LT4321IUF QFN16 LINEAR TECH LT4321IUF#PBF
54 2 STENCIL (TOP AND BOTTOM) STENCIL DC2475A
DC2475A-A
1 DC2475A – GENERAL BOM
1 1 C2 CAP, CER, X5R 10µF 16V 10% 1206 MURATA GRM31CR61C106KA88
2 1 C3 CAP, CER, X5R 10µF 16V 10% 1206 MURATA GRM31CR61C106KA88
3 1 C4 CAP, ELEC, 33µF 25V 20% 5.0X5.8 PANASONIC EEHZA1E330R
4 1 C8 CAP, CER, U2J 470pF 630V 5% 1206 MURATA GRM31A7U2J471JW31D
5 1 C9 CAP, CER, U2J 100pF 630V 5% 1206 MURATA GRM31A7U2J101JW31D
6 1 C16 CAP, CER, X7R 1µF 25V 10% 0805 MURATA GRM21BR71E105KA99L
7 1 C22 CAP, CER, X7R 3.3nF 25V 10% 0603 AVX 06033C332KAT2A
8 1 C24 CAP, CER, X7R 0.1µF 25V 20% 0603 MURATA GRM188R71E104KA01D
9 1 C25 CAP, CER, X7R 220pF 25V 10% 0603 AVX 06033C221KAT4A
10 0 D18 DIODE, DIODE INC, OPT 40V SOD323 DIODE INC OPT
11 1 E11 TP, TURRET, PAD150-094 0.094" MILL-MAX 2501-2-00-80-00-00-07-0
12 1 L1 IND, 180nH COILCRAFT DO1813P-181HC
13 1 L3 IND, CMC, 1mH WURTH 744 272 102
parts List

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dc2475aafb
DEMO MANUAL
DC2475A-A
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
14 1 Q2 MOSFET, N-CH, 100V TSON TOSHIBA TPN1600ANH
15 0 Q3 MOSFET, N-CH, OPT SOT23 OPT
16 1 Q4 MOSFET, N-CH, 200V TDSON-8 INFINEON BSZ900N20NS3
17 1 R2 RES, CHIP, 1.5k 5% 0805 NIC NRC10J152TRF
18 1 R3 RES, CHIP, 200Ω 5% 1206 NIC NRC12F2000TRF
19 1 R4 RES, CHIP, 200Ω 5% 1206 NIC NRC12F2000TRF
20 1 R8 RES, CHIP, 27Ω 5% 1206 VISHAY CRCW120627R0JNEA
21 1 R9 RES, CHIP, 27Ω 5% 1206 VISHAY CRCW120627R0JNEA
22 1 R10 RES, CHIP, 6.65k 1% 0603 NIC NRC06F6651TRF
23 1 R11 RES, CHIP, 7.50k 1% 0603 VISHAY CRCW06037K50FKEA
24 1 R14 RES, CHIP, 25mΩ 1% 1206 VISHAY WSL1206R0250FEA
25 1 R16 RES, CHIP, 0Ω, SHUNT, 0805 VISHAY CRCW08050000Z0EA
26 1 R19 RES, CHIP, 37.4Ω 1% 0805 VISHAY CRCW080537R4FKEA
27 1 R20 RES, CHIP, 1.00Ω 1% 0805 VISHAY CRCW08051K00FKEA
28 0 R23 RES, CHIP, OPT 5% 0603 OPT
29 1 R24 RES, CHIP, 26.1k 5% 0603 VISHAY CRCW060326K1FKEA
30 1 R25 RES, CHIP, 10k 5% 0603 YAGEO RC0603JR-0710KL
31 1 R26 RES, CHIP, 5.1k 5% 0603 YAGEO RC0603JR-075K1L
32 0 R30 RES, CHIP, OPT 5% 0805 OPT
33 0 R31 RES, CHIP, SHUNT, 2512 OPT
34 1 T1 XFMR, FLYBACK TRAN, 750316115 WURTH 750316115
35 0 T1 (ALTERNATE) XFMR, FLYBACK TRAN, EPC3634G PCA EPC3634G
36 0 T2 XFMR, FLYBACK TRAN, OPT OPT
37 1 U1 IC, PD AND SWITCHER CONTROLLER, LT4295IUFD QFN28 LINEAR TECH LT4295IUFD
38 1 U2 IC, TRANSISTOR OUTPUT OPTOCOUPLER, SO-8 FAIRCHILD SEMI, MOC207M
39 4 MH1-MH4 STAND-OFF, NYLON 0.50" TALL (SNAP ON) KEYSTONE 8833
40 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT 2475A
parts List

10
dc2475aafb
DEMO MANUAL
DC2475A-A
schematic Diagram
5 5
4 4
3 3
2 2
1 1
D D C C B B A A
VPORTP
T2P
-VOUT +VOUT
VPORTN
___
GND
AUX+ AUX-
12V/3A
OPTIONAL COMPONENTS
37V-57V
37V-57V
+VOUT
+VOUT
VPORTP
+VOUT
VCC
VCC
VPORTP VPORTN
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
KAUNG H.
PRODUCTION1 2 3-3-2016
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
KAUNG H.
PRODUCTION1 2 3-3-2016
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
KAUNG H.
PRODUCTION1 2 3-3-2016
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, June 02, 2016
12
HIGH EFFICIENCY IEEE802.3bt PD WITH PoE IDEAL DIODE BRIDGE
K. HTOO K. HTOO
N/A
LT4295IUFD, LT4321IUF DEMO CIRCUIT 2475A-A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, June 02, 2016
12
HIGH EFFICIENCY IEEE802.3bt PD WITH PoE IDEAL DIODE BRIDGE
K. HTOO K. HTOO
N/A
LT4295IUFD, LT4321IUF DEMO CIRCUIT 2475A-A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, June 02, 2016
12
HIGH EFFICIENCY IEEE802.3bt PD WITH PoE IDEAL DIODE BRIDGE
K. HTOO K. HTOO
N/A
LT4295IUFD, LT4321IUF DEMO CIRCUIT 2475A-A
D19
PTVS58VS1UR
2 1
HSS
R31 OPT 2512
E12
1uF C16 0805 25V
R13 100
470pF
C8
1206
R16 0 0805
R8 27
1206
T4
OPT
1 4
2 3
T1 750316115
5
6 91
3
10 7
2
8
2.2uF 100V 1210 X7R C7
C5
OPT
E9
R19
37.4
0805
R2
1.5K
R32 OPT
OPT C27 0402 1uF
C17
D1 B2100
2 1
0.047uF
C12
100V
E4
exposed pad, solder side
U1
LT4295IUFD
VPORT 28
HSGATE 26
HSSRC 25
SWVCC 23
DNC
22
VCC 21
VIN 24
PG 20
FB31
14
ISEN- 16
ISEN+ 17
SG 18
AUX
2
RCLASS++
3
RCLASS
4
GND
19
VCC
6
VCC
7
VCC
8
T2P
5
SFST
11
RLDCMP
15
VCC
9
GND
1
ITHB 13
FFSDLY 12
NC
27
ROSC
10
GND_EP
29
R11 7.50K
PE-68386NL
T3
1 3
6 4
E3
D16
PTVS58VS1UR
2 1
100pF C26 25V 0402
100uH L4
DO1608C-104
U2
MOC207
1 7 2
6 5
D13
BAT46WJ,115
12
R29
52.3K 220pF
C25
10uH L2
Coilcraft DO1608C-103
L3
1mH 744272102
1 2
34
OPT C1
R12
0
+
10uF 100V 6.3x7.7 C6
R14 25m 1206
E2
E10
R5 8.2 0805
C10
10nF
0603 100V
R17
2.00K
R22
107K
MMBT3906
Q5
1
23
OPT C15
E1
R7 20 0805
180nH L1
COILCRAFT
DO1813P-181HC
R3 200 1206
Q2 TPN1600ANH
6
4
5
8
7
1
2
3
4.7nF C23 2KV
R15
15
OPT C21
Q3
OPT
3
1
2
Q1
PSMN075-100MSE
6
4
5 8 7
1 2 3
0.1uF C24
R25
10K
R4
200
1206
D18 OPT
21
R30 OPT 0805
R24 26.1K
E11
Q7
FMMT723A
3 2
1
R20
1.00K
0805
R18 10K
+
C4 33uF 25V
EEHZA1E330R
D15 BAV19WS
2 1
OPT C19
C3 10uF X5R 16V 1206
R27
0
0402
T2
*
4
6 71
3
8 5
2
R9 27
1206
3.3nF
C22
R26 5.1K
2.2nF
C20
C2 X5R 16V 1206 10uF
D4 LED
R21 174K
Q4 BSZ900N20NS3
6
4
5
8
7
1
2
3
100pF
C9
1206
MMBT3904
Q6
1
2 3
D17 PMEG1020EA
2 1
OPT C18
10uF
C13 10V 1206
R6 3.3K
R10 6.65K
R23 OPT
VSEC_P
VPRI_SG
VAUX_P
SG
VPRI_SW
PG
VPRI_P VAUX_P
VSEC_SW
VSEC_SW
VSEC_P
VPRI_SW
VSEC_P
VPRI_P
PG
VPRI_SG VSEC_SG
VSEC_SG
VAUX_P VSEC_P

11
dc2475aafb
DEMO MANUAL
DC2475A-A
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
schematic Diagram
5
5
4
4
3
3
2
2
1
1
D D C C B B A A
OUT TO PHY
IN FROM PoE+ PSE
PoE IDEAL DIODE BRIDGE
VPORTN VPORTP
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
KAUNG H.
PRODUCTION1 2 3-3-2016
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
KAUNG H.
PRODUCTION1 2 3-3-2016
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
KAUNG H.
PRODUCTION1 2 3-3-2016
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, June 02, 2016
22
HIGH EFFICIENCY IEEE802.3bt PD WITH PoE IDEAL DIODE BRIDGE
K. HTOO K. HTOO
N/A
LT4295IUFD, LT4321IUF DEMO CIRCUIT 2475A-A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, June 02, 2016
22
HIGH EFFICIENCY IEEE802.3bt PD WITH PoE IDEAL DIODE BRIDGE
K. HTOO K. HTOO
N/A
LT4295IUFD, LT4321IUF DEMO CIRCUIT 2475A-A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] McCarthy Blvd. LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
Thursday, June 02, 2016
22
HIGH EFFICIENCY IEEE802.3bt PD WITH PoE IDEAL DIODE BRIDGE
K. HTOO K. HTOO
N/A
LT4295IUFD, LT4321IUF DEMO CIRCUIT 2475A-A
RT4 75
Q16
PSMN075-100MSE
6
4
5
8
7
1
2
3
J2 SS-6488S-A-NF
1 2 3 4 5 6 7 8
910
Q18
PSMN075-100MSE
6
4
5
8
7
1
2
3
R28 0
Q15
PSMN075-100MSE
6
4
5
8
7
1
2
3
Q17
PSMN075-100MSE
6
4
5
8
7
1
2
3
C11 0.047uF 100V
DATA2-1
CG1
1000pF
1808 2KV
RT3 75
Q14
PSMN075-100MSE
6
4
5
8
7
1
2
3
DATA1-1
D3 MMSZ5252BS 24V
2 1
Q13
PSMN075-100MSE
6
4
5
8
7
1
2
3
Q12
PSMN075-100MSE
6
4
5
8
7
1
2
3
Q11
PSMN075-100MSE
6
4
5
8
7
1
2
3
CG2 0.01uF 100V 1206
EP
U3
LT4321IUF
TG36
1
IN36
2
IN45
3
TG45
4
TG78
5
IN78
6
BG78
7
BG45
8
OUTP 12
EN 11 EN 10
OUTN 9
TG12 16
IN12 15
BG12 14
BG36 13
17
OUTN
DATA2-2
RT1 75
RT2 75
1 2 3 6 4
5 7
8
4 X 12nF
4 X 75 Ohms
1nF 2kV
J1
7499511001A
TRD1+ 11
TRCT1 12
TRD1- 10
TRD2+ 4
TRCT2 6
TRD2- 5
TRD3+ 3
TRCT3 1
TRD3- 2
TRD4+ 8
TRCT4 7
TRD4- 9
VC2 14 VC1 13 VC3 15 VC4 16
SHIELD
17 SHIELD 18
D2
PTVS58VS1UR
2 1
DATA1-2
DATA2-1 DATA2-2 DATA1-1 DATA1-2
BG12
BG36
DATA1-2 TG36 TG45 DATA2-1
DATA1-1 DATA2-2
TG12
BG45 TG45
BG36 TG36
BG12
TG78 BG78
VPORTN
BG78
DATA2-2
TG78
DATA2-1
DATA1-1
DATA1-2
TG12
BG45
VPORTN VPORTP

12
dc2475aafb
DEMO MANUAL
DC2475A-A
© LINEAR TECHNOLOGY CORPORATION 2016
LT 0517 REV B • PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application
engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation