Features• PM8805 4-pair IEEE 802.3bt compliant PD interface• Works with power supplied from Ethernet LAN cables or local auxiliary sources• Line input voltage range: 40 to 60 VDC

• Output stage managed by configurable PM8804 controller• Output voltage: 5 VDC ±2.5%• Output current: 8 A• Peak-to-peak output ripple: <50 mV• DC-DC full load efficiency: >91%• Overall full load efficiency: >90%• Transient response ΔV pk-pk 100% to 50% load step ≈ 700 mV• Switching frequency ≈ 280 KHz

DescriptionThe STEVAL-POE002V1 reference design is a two-stage converter for a powereddevice (PD), and is able to deliver up to 40 W (5 V/8 A) DC from appropriate 4-pairPoE power sourcing equipment (PSE), or an external auxiliary supply.

The first stage is the Ethernet interface is based on the PM8805 controller withintegrated full active bridge rectification. The PoE controller is compliant with the thirdgeneration IEEE 802.3bt specification (as well as the preceding 802.3af/atstandards), with improved features and increased power capacity that allow newapplication possibilities for PoE networks, including point of sales and retail logisticsdevices.

The second stage is the DC-DC converter designed around a fixed frequency flybacktopology managed by the configurable PM8804 PWM controller, with secondarysynchronous rectification via a gate driver transformer.

Product summary

PoE-PD converter basedon PM8804 and PM8805

STEVAL-POE002V1

PWM peak current modecontroller for PoE andtelecom systems

PM8804

IEEE802.3bt PoE-PDinterface with integrateddual-active bridge

PM8805

5V/8A, synchronous flyback converter, Power over Ethernet (PoE) IEEE 802.3bt compliant reference design

STEVAL-POE002V1

Data brief

DB3628 - Rev 2 - May 2019For further information contact your local STMicroelectronics sales office.

www.st.com

1 STEVAL-POE002V1 schematic diagrams

Figure 1. STEVAL-POE002V1 circuit schematic (1 of 4)

100V

IN36

19

IN36

20

Orange

FAUX

1

IN45

10

T7NM

5

2

17

Green

IN78

5

5

100V

4

3

their final value could be selected from the tablebased on the output power and Type of the PD.

7

T1

21 100V

2

4

Note for Class1 and Class2 resistors:

11

744272102

100V

J2

2

VB

C9NM

1812

2VB

4

NM

3.9K3.9K

10x10.2

R5

STBY

2KV

27VOUT

L6

B88069X9231T203-NM

26.1K

5

4

VOB

Chassis

R101k

R57

17

R20

2

C110nF0603

T0

PGD

R475R

L8

0603

C13100nF0805

C2

Ferrite bead 0805

10nF0603

R21NM

R375R

R58

NM

3

IN12

3

D3

SMA

2

VOB

BAV70

NM

D6

C52.2nF

1812

IN12

42

U20SMCNM

C1533uF-NM

100V

4

100V

B88069X9231T203-NM

R14

1%

VOUT28

23

ETH1-460

22

1 Brown

33

NC

1

U11SMCNM

U19SMC

material X7R and tolerance ±10%100 nF 100 V is X7R ±10% 0805.

08051%

IN78

RAUX11

SM15T68CA

C621nF0805

C7NM

1812

26

RV2

1

3

IN78

40

VOB

ExPadEP6

ExPad

Data output

15

1

D4

T8NM

8

GN

D12

U8SMC

10

C111 nF0603

Ferrite bead 0805

100V

1KV

R175R

C121 nF

0603

14

0805

2

RAUX

VB

T0QFN56-8X8X1-49PIN

R60

NM

IN45

4

31

8T1

Blue

744272102

SM15T68CA

C410nF0603

Note for resistors:

R675R

IN12

where not indicated the body is 0603 and tolerance ±5%

Note for capacitors:where not indicated the body is 0603, the voltage is 100 V

Chassis

1

2

T5

1

IN12

16

VOB

2010

43G

ND

7813

196

0805

L5

100V

12

CLS1

9T2

C18470 pF

0603

156

22G

ND

36

VOB

Data and power input

C8NM

1812U17SMC

T1

0603

3

100V

3

1

CLS1

1

D5

2

36IN

45

100V

16

Chassis

VDC

1

SM15T68CA

U18SMC

24

21

1KV

U1

2

1KV

Ferrite bead 0805

18

0603

PM88059

0R0CLS2

PGD25

C641nF0805

C1410nF

4

2

GND

CTRL24

0805

Chassis

14G

ND

12

VB

T2

1KV

9

L7

EP1

C19100nF0805

32

IN3623

Ferrite bead 0805

R90R

VCP

Brown

0603

20

NM0805

RV1

38 37

100V

100V

0603

9

Blue

3

35G

ND

45

8

EP5

Note for surge arrester:

8

NM0805

U21SMCNM

R107

3.9K

VOB

C65NM0805

U5SMC

75R

C102.2nF

1812

Chassis

12

Chassis

R22150R

DET

41IN

78

75R

T2

100V

6

D7

EP3

SM15T68CA

C17100nF0805

7

Note for T0 T1 T2 signals:they might not be used

U16SMC

NM

Green

R8

U10SMCNM

T6

IN45

7

C310nF0603

100V

18

ExPadEP4

ExPad

R775R

C16

4.7uF1210

4

AGND7T0

STBY

R19

T1

foreseen on PCB footprint forB88069X9231T203

0603

100V

R59G

ND

36

Chassis

29VDD30

U9SMC

0603

J1

1

GN

D78

SM15T68CA

39 34

3

10FAUX

2KV

U7SMCNM

ExPadEP2

ExPad

0603

U6SMCNM

6

1

13

VOB

3

2

R18

1

2

C6NM

1812

Orange

100V

GN

D45

08051%

0805

10

R275R

R2336R5

Figure 2. STEVAL-POE002V1 circuit schematic (2 of 4)

C86NM

100k

0805

3

D14

2

C82

D43

C84

SOD323

STBY

BAT

46J

VDC

SMC

0R-NM

D45

10nF

0R-NM

GND

SMC

SHDN

D46

BAT

46J

FAU

X

0805

C85NM

SOD323R122

47K

R115

R12147K

0805

Rau

x +l

ive

PoE

J9

3

2

SOD323

R117

100k

R751k

D47

3k9

BAT

46J

RAUX

D44

J10

BAT

46J

CLS1

D37

2

R114

SOD323

R118

1STTH302S

R670R-NM

BAT

46J

P2

3

AUX Rear

4

STB

Y H

igh

D42

AUXF

SOD323

R116R77

FAUX

R0805

STBY

VOB

10nF

SLEEP/WKUP

SOD323

AUX Front

3

3k9C83

D40

BAT

46J

RAUX

100k

VB

STTH302S

1

R760R

FAUX

0805

R69100k

R119

R1231k

STB

Y

0805

D41

0805

P1

D20

AUXR

Aut

oCla

ss

RA

UX

2

VB

4

1

3k9

SOD323

R12010nF

D391B

AT46

J

STEVAL-POE002V1STEVAL-POE002V1 schematic diagrams

DB3628 - Rev 2 page 2/5

Figure 3. STEVAL-POE002V1 circuit schematic (3 of 4)

1%

SGND

47nF

2KV

R2910R

33nFDT 50ns 91K

C244.7µF1210

VOU

T Le

d

C542200pF

1812

2

VSN

SOT23 SOT23

R273Mega

D11

100V

0805

turret

1

NC1

R33

6Q2

SOD323

0603

C511nF0805

S1

R4682k

1

680R

C461nF0805

C26NM0805

16V

2

VSN

2

NoteFeedback loop must be fine tuned taking into account also theoverall capacitance due to

VDC

C58

Note

6.3V

R35

STL110NS3LLH7

synch MOSFETN ch 60 V 10 milli max Qt <30nc

PGND

V5V

G4

16QFN_3X3X0.75_0.5

C60

SGND

C31

4.7µF1210

0805

11G

AT2

VC

J4

0603

10K

10x10.2

R44R100

R47

R412K2

5

3

R49

0R

CS

C27NM

TP10

R26

0R

6

10K

C391nF

MMBT3906LT1

D9BAS70

C56NM

100nF

6K8

R5220k1%

R62NM

R3420R

PGND

PGND

0805

D5

C36

100µF1210

2

PGD

10K

1

Fsw 300khz 82K SS 10ms

100pF

Input Filter

C2933µF100V

2KV

0603

1206

D7

Alternative primary MOSFET

C20NM

1812

SGND

C342200pF

1812

C222200pF

1812

C41

100µF1210

4

G4

9

CoilCraft NA6083-BL

11

R24

0R

GAT

1

10PG

ND

0805BZX84C10-NM

R53

U4

0603

R30NM

TS431AILT

2

3

Q4

0603

0805

C5333nF

J6

Note

Note

PowerFLAT 5x6

C33

4.7µF1210

2

Power circuit

Feedback circuit

2KV

C25100pF

TP9

C52

2KV

2KV

C59

0805

VINpf

8VIN

BSC500N20NS3G

R4591K

L20R1

0805

16V

C37

100µF1210

U3

8

C50100nF

25V

DO3316H-121MLD

Q3

0805

VSP

D8

4

C43

330µF-NM

8x10.5

SGND

Common Mode Filter

C32

4.7µF1210

R4810R

R51

GND

C38

100µF1210

R5512K

PowerFLAT 5x6

C212200pF

1812

C57

S1

T3

CQ1

3.3K

1%

D8

C352200pF

1812

A

12

3D

T

SOD323

R25100R

0805

1

S3

100V

1206

COILCRAFT DA2319-AL

FOD817AS

PGND

16V

VINnf

1%

T4

R108R100

5

SOD323

S2

330R

R42

9

XAL5050-562

Chassis

16V

100V

C45NM25V

2010

SOD323

16V

1

R31NM

0805

C49

100nF25V

0805

7NC2

6PGD

24

1

12

10

0805

BSC039N06NSAlternative synch MOSFET

L4120nH

R3210R

1

R40

D13

BAS70

MMBT3904LT1-NM

D10BAS70

C30NM

the electronics circuits that the converter is powering

D15

PGND

MODE13

16V

1%

D12BAS70

0805

SGND

100V

NC

100V

C40

100µF1210

R50

SGND

100V

T2NM

0603

SMA

SOT23-55

1L30R

C28NM

SOT23

PM8804

100V

1%

100V

U2

turret

C42

100µF1210

fine tuned in the final application

R3810R

150nF

S3D

6

Note

17

NotePM8804 parameters must be

Primary MOSFETN ch 150-200V 50 milli max Qt <30nc

EEEFK2A330P

R43

FDMS86252

3

Ex Pad

VGS

3

R370R

R56

22nF

X5RX5R

0805

R3610R

C48

D7

1206

Blanking 70ns 130K

BLK16

10k

7

1

S2

FSW

2SSAG

ND

14

CTL15

C552.2µF25V

R28150R

R5415K1%

L1

4

0805

0805

2

Internal auxiliary voltage must be set between 9V and 10V from no load to full load

NM

X5RX5RX5RX5R

Note

C472.2µF25V

D5

Auxiliary voltage

4

C231nF0805

100pF

R613.3K

3

130K

1%

4

D82KV

D6

C44

100nF

1K5

Figure 4. STEVAL-POE002V1 circuit schematic (4 of 4)

1%

R110NM

U12

V5V

SGND

C74

NM

PGND

D36NM

U14

Noteplace the optional circuit on the bottom side.

1N4148WS-NM

R1060R

1

0805

5

SGND

1

4

2

1VCC

100R

SRK1000-NM

0RR109

NM

TS431AILT

3

R112

2 4

VAUX

6DVS

D35

VGS

R10439K

1%3TS2431-NM

NM

3

U13

SOD323

330R

VSN

10603SOT23

2

C78

SOT23-51%

U15

2

C76

NMR101

R102

PGD

GND3

GD

R1130R

C75

BAS70-NM

100p1uF

1

FOD817AS

D38

V5V

C81NM47K

2

4TON

5

R105

SOD323

R111 R10312K

STEVAL-POE002V1STEVAL-POE002V1 schematic diagrams

DB3628 - Rev 2 page 3/5

Revision history

Table 1. Document revision history

Date Version Changes

16-Oct-2018 1 Initial release.

02-May-2019 2 Updated cover page title and Description

STEVAL-POE002V1

DB3628 - Rev 2 page 4/5

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STEVAL-POE002V1

DB3628 - Rev 2 page 5/5