12 V/8 A, active clamp forward converter, Power …...12 V/8 A, active clamp forward converter, Power Over Ethernet (PoE) IEEE 802.3bt compliant reference design AN5207 Application

IntroductionThis reference design represents a 3.3 V, 20 converter solution ideal for various applications including wireless access points,supplied with a PoE-PD interface and a DC-DC active clamp forward converter.

The PoE-PD interface is based on the PM8805 system in package device with two active bridges and an IEEE 802.3btcompliant Powered Device (PD) interface. It can be used in all medium-to-high power 2P and 4P high efficiency PoE and PoE+applications.

The DC-DC active clamp forward converter is designed around the PM8804 PWM controller, which is an integrated solution forsmart and efficient 48 V converters, featuring a programmable oscillator for the switching frequency, adjustable slopecompensation, dual complementary low-side drivers with programmable dead time, programmable soft start, soft turn off and aprogrammable current sense blanking time.

Figure 1. STEVAL-POE005V1 reference design

12 V/8 A, active clamp forward converter, Power Over Ethernet (PoE) IEEE 802.3bt compliant reference design

AN5207

Application note

AN5207 - Rev 2 - May 2019For further information contact your local STMicroelectronics sales office.

www.st.com

https://www.st.com/en/product/pm8805


1 STEVAL-POE005V1 reference design overview

1.1 Specifications, connectors and LEDs

Table 1. STEVAL-POE005V1 specifications

Parameter Specs

VIN at RJ45 connector From 41.2 to 57 V

IIN at RJ45 connector 1.0 A max. each pair

VOUT 12 V ± 2%

IOUT 8 A total max.(1)

Max. ouput power 100 W(2)

Efficiency overall peak>92% at 5.5 A

>90% at 8 A

VIN at Frontal Jack connector (J9) 48 V ±2 V

IIN at Frontal Jack connector (J9) 2.0 A total max.

VIN at Rear Jack connector (J10) 48 V ±2 V

IIN at Rear Jack connector (J10) 2.5 A total max.

Operating temperature0°C - 50°C 8 A full load

50°C - 85°C linearly decrease to 5.5 A

1. There are two limits to play with: the power limits specified in the BT standard→ Class 8 means 71 W min. available at PDinterface with the specified efficiency of about 5.5 A at the output; the PM8805 current limit → 2 amp min., about 2.5 Atypical, that is, to reach 8 amps on the output the PoE input voltage must be of at least 56 V or an auxiliary rear input sourcemust be capable of about 110 W. In fact, the max. power can be reached using the rear input, to bypass the PM8805 currentlimit circuit.

2. The max. power cannot be maintained at a high ambient temperature ( Tamb > 50°C ) for a long time.

Table 2. STEVAL-POE005V1 connectors

Reference Type Specs

J1 RJ45 connector Data and power input

J2 RJ45 connector Data output

J9 Power jack Front Aux

J10 Power jack Rear Aux

J4, TP10 Banana jack/turret Positive of VOUT

J6, TP11 Banana jack/turret Negative of VOUT (Sec GND)

TP8 Test point Monitor of VOUT

TP9 Test point Monitor of Sec GND

P1 Push button SLEEP/WKUP

P2 Push button SHDN

AN5207STEVAL-POE005V1 reference design overview

AN5207 - Rev 2 page 2/47

Table 3. STEVAL-POE005V1 LEDs

Reference Type Function Logic

D4 Green LED Monitor of T2 signal LED on when T2 is low



D15 Green LED Monitor of VOUT LED on when VOUT is present

D39 Green LED Monitor of FAUX signal LED on when frontal aux ispresent

D40 Green LED Monitor of STBY signal LED on when STBY is high

D44 Green LED Monitor of RAUX signal LED on when rear aux ispresent

Table 4. Tx signal possible configurations

Classification T0 T1 T2 Bridges Finger number Notes

Type 1 (13 W) 1 1 1 1 0 or 1 Legacy type

Type 2 (25.5 W) 0 1 1 1 2, 3 Legacy type

Type 3 (51 W) 1 0 0 2 4 New PD type

Type 4 (71 W) 0 0 0 2 ≥ 5 New PD type

Type 3 on 4pairs (13 W), orlegacy 4 pairs(type 1 class)

1 1 0 2 0 or 1 New PD type

Type 3 on 4pairs (25.5 W),or legacy 4pairs (type 2class)

0 1 0 2 2, 3 New PD type

Rear AUX0 0 1

anyN.A. Aux present

Front AUX 0

The STEVAL-POE005V1 reference design is classified as type 4 and class 8. The default status of Tx signal is000.

Note: Level 0 or low means the corresponding LED is on; level 1 or high means the LED is off.

AN5207Specifications, connectors and LEDs

AN5207 - Rev 2 page 3/47

https://www.st.com/en/product/steval-poe005v1

1.2 Board setupThe STEVAL-POE005V1 reference design combines the PM8805 PD interface, compliant with the IEEE 802.3btPoE standard, and the PM8804 PWM controller for an active clamp forward.

Figure 2. STEVAL-POE005V1 reference design: component view

• 1. POE IN• 2. RAUX IN• 3. FAUX IN• 4.SLEEP and WAKEUP• 5.SHUTDOWN• 6.OUTPUT

12

3

4 56

When you use a bench power supply, follow the steps below.

Step 1. Set the power supply current limit to 0.2 AStep 2. Apply 10 V and check the input current is 350-400 µAStep 3. Apply 20 V and check the input current is within the selected Class range (the default is Class 8, 39

mA)Step 4. Apply 48 V and check the input current is <60 mA and the output voltage is 12 V (without load)Step 5. Change the current limit to 3 AStep 6. Connect an electronic load between VOUT and the secondary GNDStep 7. Turn the power supply on (48 V) and check the input current is coherent with the load current setting

and the converter expected efficiency.For example, 12 V x 5.5 A = 66 W→expected efficiency is 92% so PIN = 66/0.92=71.74 W, which, with48 V as input voltage, gives Iinput =71.74/48 =1.5 A

Step 8. Change the load current as needed

AN5207Board setup

AN5207 - Rev 2 page 4/47




2 Configurations

2.1 PM8805 configurations

Table 5. PM8805 control signal description

PM8805behavior,st

andardoperations

INPUTS OUTPUTS

FAUX RAUX STBY PGD Hot swap Chargepump

Activebridge MPS

NormalPOE

operation0 0 0

1 after85ms hot

swapenabled

Closes atUVLO

On @UVLO Enabled Off

Stby PoEoperation 0 0 1 1 when hot

swap closedCloses at

UVLO Off LS enabledHS OFF On

Front Auxoperation 1 0 x 1 when hot

swap closed Closed On Enabled Off

Rear Auxoperation 0 1 0 1 Open Off Off Off

Additional non standard operations

Sleepmode/Wake

up1 1 1 0 Open Off LS enabled

HS OFF On

Rear Auxwith MPS 0 1 1 1 Open Off LS enabled

HS OFF On

Shutdown/reboot 1 1 0 0 Open Off Off Off

2.2 PoEThe STEVAL-POE005V1 reference design default operation mode is the PoE (0,0,0). The selected class resistorsare 36.5 ohm for CLS1 and 51.1 ohm for CLS2, so the board is class 8; that is, the Tx LED configuration is 000 orall LEDs on.The other classes can be adjusted using the following table.

Table 6. PM8805 class description

PD class CLS1 resistor (Ω) CLS2 resistor (Ω) Min. (mA) Max. (mA)

Class 0 2 K 2 K 0 4.0

Class 1 150 150 9.0 12.0

Class 2 80.6 80.6 17.0 20.0

Class 3 51.1 51.1 26.0 30.0

Class 4 36.5 36.5 36.0 44.0

Class 5 36.5 2 K 36/0 44/4

Class 6 36.5 150 36/9 44/12

Class 7 36.5 80.6 36/17 44/20

AN5207Configurations

AN5207 - Rev 2 page 5/47


PD class CLS1 resistor (Ω) CLS2 resistor (Ω) Min. (mA) Max. (mA)

Class 8 36.5 51.1 36/26 44/30

Classification phase is valid only for PoE devices, so it is not required when connected to any non-PoE powersource such as a wall adapter: in those cases, the CLS buffers are never turned on.Depending on the PD type and class, the relevant PD electrical parameters are summarized in the table below.

Table 7. PM8805 PD main parameters

PD type Class CLS1 sign. CLS2 sign. Pin (W) Vin min. (V) Vin max.(V)

IIN max.(mA)

Ppeak (W)for 50 ms

1

0 0 0 13.0 37.0

57

350 14.4

1 1 1 3.84 42.1 90 5.00

2 2 2 6.49 40.8 160 8.36

3 3 3 13.0 37.0 350 14.4

2 4 4 4 25.5 42.5 600 28.05

3

1 1 1 3.84 42.1 90 5.00

2 2 2 6.49 40.8 160 8.36

3 3 3 13.0 37.0 350 14.4

4 4 4 25.5 42.5 600 28.05

5 4 0 40.0 44.3 900 42

6 4 1 51.0 42.5 1200 53.55

47 4 2 62.0 42.9 1440 65.10

8 4 3 71.3 41.2 1730 74.86

2.3 FAUX connectorA voltage applied at J9 connector (FAUX) sets automatically the correct input configuration (FAUX=1, RAUX=0,STBY=do not care).If the STEVAL-POE005V1 reference design is already powered by a PSE, the following conditions apply:1. FAUX voltage lower than PSE voltage: the board is still powered from PSE and T0,T1,T2 signal

configuration remains the same according to Table 42. FAUX voltage is greater than PSE voltage, but the difference is less than 2 V: a current sharing occurs

between PSE and FAUX to supply the board. T0,T1,T2 signal configuration remains unchanged as in theprevious case

3. FAUX voltage is greater than PSE voltage and the difference is greater than 2 V: the board is powered byFAUX, PSE is disconnected as its load has significantly decreased (~3 mA) and PD does not ensure MPScondition.The PM8805 device works in Front aux mode (T0=0,T1=0,T2=1). When the FAUX connector (J9) isunplugged, PSE is not connected and the output voltage is interrupted as a new detection/classificationprocedure must be done before PSE powers the board again.

2.4 RAUX with MPSA voltage applied at J10 connector (RAUX) sets automatically the correct input configuration (FAUX=0; RAUX=1;Stby=1).The hot swap MOSFET is opened to give prevalence of the RAUX source over the PoE interface.The STEVAL-POE005V1 reference design is configured to put the PSE in MPS mode triggering the STBY pinthreshold by a proper divider (R69, R76 and R120) supplied by the RAUX input voltage. When STBY pin is pulledup, MPS current is enabled and drawn from the PSE.

AN5207FAUX connector

AN5207 - Rev 2 page 6/47




The RAUX voltage can be in one of the following ranges, depending on the PSE voltage available at RJ45connector (J1):• RAUX voltage lower than PSE input voltage of less than 10 V: when RAUX voltage is applied and the board

is already powered by PSE, switching between the two power supply sources works properly. The PM8805device goes in Rear auxiliary with MPS mode and PSE remains connected to the board (T0=0,T1=0, T2=1)

Figure 3. PSE to RAUX switchover at VPSE=55 V, VRAUX=48 V, IOUT=5.5 A

– Ch1: VDC input voltage (TP5); Ch2: PSE input current (J1 twisted pairs)– Ch3: RAUX signal (pin 11 U1 - PM8805); Ch4: RAUX input current (J10)

When RAUX power supply is unplugged from J10, PSE is immediately available to supply the board, withoutcausing output voltage interruptions, and the PM8805 device goes back to normal operating mode.As shown in the figure below, there is a delay of about 200 µs between the time the RAUX source isunplugged and the hot swap MOSFET of PM8805 is turned on again, during which the forward converter issupplied only by input capacitors C29 and C15.

AN5207RAUX with MPS

AN5207 - Rev 2 page 7/47


Figure 4. RAUX to PSE switchover at IOUT=5.5 A, VRAUX=48 V, PSE voltage=55 V

– Ch1: VDC input voltage (TP5); Ch2: PSE input current (J1 twisted pairs)– Ch3: Vout output voltage (TP8); Ch4: RAUX signal (pin 11 U1 - PM8805)

• RAUX voltage lower than PSE input voltage of more than 10 V: when RAUX voltage is applied and theboard is already powered by PSE, switching between the two power supply sources works properly as in theprevious case. When RAUX power supply is unplugged from J10, during the switchover, the PM8805 hotswap MOSFET drop between drain and source might be greater than the datasheet parameter Vds_fail (12V min./16 V max.).If this failure occurs, the power good signal is forced to low level according to the datasheet parameterTretry (9 min./11 max. msec), stopping the forward converter switching, then it is released causing an outputvoltage interruption as shown in the following figure.

AN5207RAUX with MPS

AN5207 - Rev 2 page 8/47

Figure 5. RAUX to PSE switchover at IOUT=5.5 A, Aux Rear = 44 V, PD voltage = 55 V

– Ch1: VDC input voltage (TP5); Ch2: Vout output voltage (TP8)– Ch3: RAUX signal (pin 11 U1-PM8805); Ch4: PGD signal (TP19)

• RAUX voltage is greater than PSE input voltage of at least a diode forward voltage: when RAUX voltage isapplied and the board is already powered by PSE, switching between the two power supply sources worksproperly as reported in the previous cases, but in this condition MPS current is drawn by RAUX source, thenPSE is no more able to stay connected to the board. In this case, when RAUX source is removed, the outputvoltage goes to zero until PSE has successfully completed detection and classification phases, and thevoltage is reapplied to the PD interface.

2.5 Soft stopAn important feature of the PM8804 is the soft stop that can be controlled via the MODE pin, used to select theconverter operation mode.By connecting this pin to AGND, you can turn GATE2 off when not used and disable the soft stop feature.Pull up MODE pin if GATE2 is used and soft stop desired. Leave this pin open when not used.In case of normal shutdown or thermal fault, the device features a soft stop procedure which helps to reduce thestress and the overvoltage on the power MOSFET and it is achieved discharging slowly the soft start capacitorwith a 10 µA current sink. On the STEVAL-POE005V1 reference design the MODE pin is left open, as GATE2must be available to implement the active clamp forward converter and, during normal shutdown, the soft stopprocedure is implemented.

AN5207Soft stop

AN5207 - Rev 2 page 9/47



3 Measurements

3.1 EfficiencyThe STEVAL-POE005V1 reference design consists of a PoE interface compliant with the IEEE 802.3bt standardand a forward active clamp DC-DC converter that receives DC voltage from the PoE interface.The figure below shows the efficiency of a single forward converter and the overall efficiency including the PoEinterface power losses.

Figure 6. STEVAL-POE005V1 overall and DC-DC forward efficiency

The dotted lines indicate the STEVAL-POE005V1 efficiency at different DC input voltages applied to RJ45connector J1. The continuous line indicates the DC-DC forward efficiency, which does not include the followinglosses associated with the PoE interface section:• RJ45 connector J1• PoE data transformer T1• common chokes T7 and T8 placed on the two power supply pairs• PM8805 interface that integrates the dual power MOS bridges and a hot swap MOSFET• Forward converter input filter

This efficiency is measured between output test points TP8/TP9 and input test points TP5/TP6 of the forwardconverter.

AN5207Measurements

AN5207 - Rev 2 page 10/47




3.2 Output voltage ripple

Figure 7. Output voltage ripple: IOUT= 800 mA

• Ch1: Vout ripple; Ch2: Primary MOSFET gate voltage; Ch3: IOUT

AN5207Output voltage ripple

AN5207 - Rev 2 page 11/47

Figure 8. Output voltage ripple: IOUT= 8 A

• Ch1: Vout ripple; Ch2: Primary MOSFET gate voltage; Ch3: IOUT

AN5207Output voltage ripple

AN5207 - Rev 2 page 12/47

3.3 Input voltage ripple

Figure 9. Input voltage ripple before and after forward input filter: VIN = 48 V, IOUT = 800 mA

• Ch1: Vin ripple before input filter (TP5); Ch2: Primary MOSFET gate voltage• Ch4: Vin ripple after input filter (C33); Ch3: Input current (J1 connector pairs)

AN5207Input voltage ripple

AN5207 - Rev 2 page 13/47

Figure 10. Input voltage ripple before and after forward input filter: VIN = 48 V, IOUT = 8 A

• Ch1: Vin ripple before input filter (TP5); Ch2: Primary MOSFET gate voltage• Ch4: Vin ripple after input filter (C33); Ch3: Input current (J1 connector pairs)

AN5207Input voltage ripple

AN5207 - Rev 2 page 14/47

3.4 Startup

Figure 11. Output voltage at startup: Iout at no load, Vin= 48 V

• Ch1: Vout; Ch2: Soft start voltage (C53); Ch4: primary MOSFET gate voltage

AN5207Startup

AN5207 - Rev 2 page 15/47

Figure 12. Output voltage at startup: Iout=8 A, Vin= 48 V

• Ch1: Output voltage; Ch2: Soft start voltage (C53);Ch4: Output current; Ch3: primary MOSFET gate voltage

AN5207Startup

AN5207 - Rev 2 page 16/47

3.5 PoE connector unplugged power off

Figure 13. Power off at primary side: Iout=8 A, Vin= 42 V

• Ch1: Primary Q4 MOSFET drain voltage; Ch2: Forward input voltage (TP5)• Ch3: Soft start voltage (C53); Ch4: Power good (TP19)

AN5207PoE connector unplugged power off

AN5207 - Rev 2 page 17/47

Figure 14. Power off at secondary side (Q1): Iout=8 A, Vin= 42 V

• Ch1: Primary Q4 MOSFET drain voltage; Ch2: Secondary Q1 MOSFET gate voltage• Ch3: Secondary Q1 MOSFET drain voltage; Ch4: Power good (TP19)


AN5207 - Rev 2 page 18/47

Figure 15. Power off at secondary side (Q5): Iout=8 A, Vin= 42 V

• Ch1: Primary Q4 MOSFET drain voltage; Ch2: Secondary Q5 MOSFET gate voltage• Ch3: Secondary Q5 MOSFET drain voltage; Ch4: Power good (TP19)


AN5207 - Rev 2 page 19/47

3.6 Primary side waveforms

Figure 16. Primary steady state: Iout=800 mA, Vin= 48 V

• Ch1: Primary Q4 MOSFET drain voltage; Ch2: Primary current sense voltage• Ch4: Primary MOSFET gate voltage

AN5207Primary side waveforms

AN5207 - Rev 2 page 20/47

Figure 17. Primary steady state: Iout=8 A, Vin= 48 V

• Ch1: Primary Q4 MOSFET drain voltage; Ch2: Primary current sense voltage• Ch4: Primary MOSFET gate voltage

AN5207Primary side waveforms

AN5207 - Rev 2 page 21/47

3.7 Secondary side waveforms

Figure 18. Secondary steady state: Iout=800 mA, Vin= 48 V

• Ch1: Secondary Q1 MOSFET drain voltage; Ch3: Secondary Q5 MOSFET drain voltage• Ch2: Secondary Q1 MOSFET gate voltage; Ch4: Secondary Q5 MOSFET gate voltage

AN5207Secondary side waveforms

AN5207 - Rev 2 page 22/47

Figure 19. Secondary steady state: Iout=8 A, Vin= 48 V

• Ch1: Secondary Q1 MOSFET drain voltage; Ch3: Secondary Q5 MOSFET drain voltage• Ch2: Secondary Q1 MOSFET gate voltage; Ch4: Secondary Q5 MOSFET gate voltage

AN5207Secondary side waveforms

AN5207 - Rev 2 page 23/47

3.8 Load transient side waveforms

Figure 20. Load transient: Iout=4 to 8 A, Vin= 48 V

• Ch1: Output voltage; Ch2: Output current

AN5207Load transient side waveforms

AN5207 - Rev 2 page 24/47

3.9 Gloop measurements

Figure 21. Gloop plot (Vin= 48 V, Iout=6 A)

Figure 22. Gloop plot (Vin= 48 V, Iout=0.8 A)

Figure 23. Gloop plot (Vin= 42 V, Iout=6 A)

AN5207Gloop measurements

AN5207 - Rev 2 page 25/47

Figure 24. Gloop plot (Vin= 42 V, Iout=0.8 A)

3.10 Board thermography

Figure 25. STEVAL-POE005V1 reference design thermography at 8 A, 56 V (emissivity = 0.95, reflectedtemperature = 20°C

• SP1 (Q1 secondary rectifier MOSFET) = 78.4°C• SP2 (Q5 secondary freewheeling MOSFET) = 77.3°C• SP3 (Q4 primary main MOSFET) = 87.1°C• SP4 (T3 forward transformer) = 85.4°C• SP5 (L4 output inductor) = 80.3°C• SP6 (U1 PM8805) = 66.2°C• SP7 (Reference point) = 45.6°C

AN5207Board thermography

AN5207 - Rev 2 page 26/47

Figure 26. STEVAL-POE003V1 reference design thermography at 6 A, 41 V (emissivity = 0.95, reflectedtemperature = 20°C

• SP1 (Q1 secondary rectifier MOSFET) = 63.1°C• SP2 (Q5 secondary freewheeling MOSFET) = 64.3°C• SP3 (Q4 primary main MOSFET) = 73°C• SP4 (T3 forward transformer) = 71.5°C• SP5 (L4 output inductor) = 63°C• SP6 (U1 PM8805) = 60.9°C• SP7 (Reference point) = 43.4°C

AN5207Board thermography

AN5207 - Rev 2 page 27/47

4 STEVAL-POE005V1 schematic diagrams

Figure 27. STEVAL-POE005V1 circuit schematic (1 of 3)

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ND

2

43

21

C89

10nF

-NM

250V

DAT

A O

UTP

UT

250V

R21

NM

IN1215

9

U21

SM

AN

M

11

U7

1KV

1210

SM

CN

M

GND36ExP

ad

T5 NM

TP-R

edTP

17

NO

TE fo

r Cla

ss1

and

Cla

ss2

resi

stor

s

thei

r fin

al v

alue

cou

ld b

e se

lect

ed fr

om ta

ble

base

d on

the

outp

ut p

ower

and

Typ

e of

the

PD

.

1

100V

C11 1nF

0805

U11

NM

SM

C

R19

U20

SM

AN

M

16 23

C97

47K

1%

C61 33nF

0805

Blue

12

R7

AN5207STEVAL-POE005V1 schematic diagrams

AN5207 - Rev 2 page 28/47


2

SMC

R13

1

1%

AutoClass

1k

C78

3

0805

4k7

VB

1%

BAT46J

D43

3

NM

TP4

STBY

2

1nF

VDC

12

100K

C84

VB

FOD

817A

S

R12

3

C81

SOD

323

RAUX

TP2

R11

9TP

1

4

TP-R

ed

R13

0

R75

1k

P1

4k3

U23

SOD

323

3

SLEE

P/W

KU

P

R10

5

GN

D

41

Raux +live PoE

SOD

323

OVP

AU

X R

ear

0805

STPS

4S20

0S

R11

7

MO

DE

D45

FAUX

BAT46J

R08

05

R76

0R

330R

D52

VOU

T

0

C82

D42

R12

7

1%47

0K

BAT46J

GND

D14

PGD

0805

J10

R11

4

TP-B

lack

R12

120

K

22nF

1%

AUXR

TS43

1AIL

T-N

MSO

T23-

55

R12

247

K

CLS

1

SOT-

23

J9

0805

C83

1 2 3

0805

1 2 3

3

R11

6

D53

STBY High

R67

0R-N

M

SOT2

3

Q14

2N70

02

R13

3

1

RAU

X_M

AN

D37

3

SHD

N

D46

SOD

323

STBY

BAT46J

0805

U24

0805

U22

R10

21K

SOD

323

R11

5

D51

BAS70

1

TP-R

ed

FAU

X

D41

NM

R13

2

AU

X Fr

ont

4k7

D39

TS24

31-A

ILT

GN

D

1nF

SOD

323

R12

9

1nF

C86

NM

4 12

Q13

2N70

02

0R-N

M

R10

456

K1%

D20

P2

STBY

BAT46J

STPS

4S20

0S

R11

8

NM

R10

1

BAT46J

RAU

XSO

T23

C85

20K

SOT-

23

OVP

SOT2

3

R77

SMC

1%

100k

R12

810

K

2

AUXF

1%

D40

D47

SOD

323

R10

312

K

VOB

4

BAT46J

100k

TP-B

lack

R12

610 1%

SOD

323

R12

0

BAS7

0-05

TP3

BAS7

0-05

FAU

X_M

AN

NM

6K8-

NM

0R

SSSG

ND

D44

2.2K

-NM

R69

100k


AN5207 - Rev 2 page 29/47


D7

0805

16V

200V

2KV

2KV

SOD

323

S2

C59

R54

4K64

1%

C52SM

A

C32

4.7u

F12

10

L1 5.6u

H

11

VC12

5

S1D5

0603

C55 10

0nF

25V

100V

R33

5R6-

NM

VSP

7

7503

7022

5 R

ev 0

3

TP-R

ed

STL9

0N6F

7

Cha

ssis

GN

D

0603

1%

R43

130K

TP-R

ed

D7

Auxi

liary

vol

tage

3

Inpu

t Filt

er

TP7

C29

33uF

100V

D49

BAS7

0

C43 100u

F

100n

F

Q9

3

NC

0805

NM

0805

Q2

6

100V

C

C38

47uF

1210

SOT2

3

10K

GSH

S2

1

SOT2

3

TP6

R12

5

0805

2

G4

GSH

0603

S3

SS2

NM

T3

D8

D13

BAS1

6JD8

4

PGN

D

D11

4

PBSS

4240

T

0R

D16

BAS1

6J

VOUT Led

D7

R40

C26

1nF

0805

1206

Ex P

ad

11 8

SGN

D

8

2

R62

NM

Q3

C54

2200

pF

1812

Q5

G4

CTL

D6

U4

3

R55

5K23

J6

TP11

PGN

D

D7

POE1

20PL

-xxL

_-N

M0R

1

1206

D8

NC

0805

R41

NM

R30

NM

D8

NC27

GAT

1

PGN

D10

1206

TP14

VSP

0805

C20

NM

1812

AGN

D

C50

100n

F25

V

D5

NC

SGN

D

C21

2200

pF18

12

C35

2200

pF-N

M18

12

R26

0R

S1

4.7K

1%

R61

10k

VIN8

C25

100n

F

SMA

J58A

2

D6

TP-R

ed

0805

R46

91K

C33

4.7u

F12

10

5

R52

20k

1%

SGN

D

0805

TP-R

ed

R50

390R

SGN

D

R24

0R

R34

R17

Q11

C44

100n

F06

03

L9 1mH

R25

10K

G4

100V

T4

SGN

D

C37

47uF

1210

S3

D8

22nF

Pow

er c

ircui

tFe

edba

ck c

ircui

t

GSL

2

10 9

R37

Q1

4

STL9

0N6F

7-N

M

C96

2.2u

F25

V

S1

0805

4 1

R16

5R6-

NM

Q8 ST

L90N

6F7-

NM

MODE13

0603

10K

SOD

323

0603

VSN

D7

BSC

190N

15N

S3

S2

VSN

TP5

C36

47uF

1210

16V

R56

C

C48

47nF

1206

BZX8

4C10

-NM

R48

D2

D15

PBSS

5240

T-N

M

17

2K

Wur

th 7

4439

3460

56

C41

47uF

1210

16V

2

1

4

LPS4

018-

105M

L

D12

BAS7

0

0603

PBSS

5240

T-N

M

C30 NM

C27

NM

Fairc

hild

FO

D81

7AS

D5

C49

NM

1206

GAT

2

15

1210

SOT2

3-5

SOT2

3

5

22R

S1

C51

1nF

0805

PGD

1%

25V

Pow

erFL

AT 5

x6

1K

D8

2KV 08

05Po

wer

FLAT

5x6

Pow

erFL

AT 5

x6

D6D7

SOT2

3

220p

F

TP12

6PGD

100V

D50

BAS7

0

U2

R15

NM

PM88

04

C58

S2S3

50V

10

C56

NM

3

TP-R

ed

pow

erFL

AT 5

x6

TP-B

lack

TP-R

ed

L2 0R

2

C24

4.7u

F12

10

1

DT

3

C40

47uF

1210

16V

NM

R38

10R

1

AGN

D

VSP

0805

D48

BAS1

6J

2 1

C57

22nF

NM

S3

10k

100V

SOT2

3

22R

D8

SGN

D

SS

EEEF

K2A3

30P

SGN

D

16V

PGN

D

2KV

C60

SOT2

3

0603

7443

6310

00

Q10

12

A

turre

t

0805

VOU

T

R12

418

R

1

0603

G4

D5

C46

1nF

0805

STL9

0N6F

7

0805

C39

1nF

NM

D9

BAS1

6J

6.3x

5.8m

m

CS14

1

R28

0R

S2

R53

U12

S3

SGN

D

S1

pow

erFL

AT 5

x6

2

SOD

323

R47

2K

2KV

SOT2

3

1206

TP8

TP-B

lack

U3

S3D6

BZX8

4C10

16V

50V

L4

R27

3M-N

M

Q7

R36

10R

R45

330K

VSN

C34

2200

pF18

12R

3510

0V

S1

1K

TS43

1AIL

T-N

M

0805

C45

100n

F25

V

T2 NM

D5

R29

NM

TP13

SOD

323

VDC

J4

Sync

hron

ous

rect

ifier

s

R78

0R

This

circ

uit a

t the

bot

tom

sid

e un

der

the

equi

vale

nt c

ircui

t of t

he to

p si

de

D6

C47

2.2u

F25

V

47K

6

100p

F

C95

1nF

1

A

Q4

TP9

2

C22

2200

pF-N

M18

12

R51

D5

C28

NM

1

GSL

SOD

323

MO

DE

L3

2

turre

t

G4

FDM

C86

259P

100V

C75

100p

F08

05

MM

BT39

04LT

1-N

M

A

C42

47uF

1210

16V

NM

Q12

1210

SOD

323

16Q

FN_3

X3X0

.75_

0.5

AGN

D

BLK16

R44

0R05

5NC1

2

0603

C23

1nF

0805

D1

PGN

D

SOD

323

C31

4.7u

F12

1010

0V

200V

SOD

323

3

D17

BZX8

4C10

C

R32

10R

SOT2

3

C53

10nF

PBSS

4240

T

R10

80R

100

4FS

W

BAS1

6J

TP10

D6

G4

2KV

10x1

0.2

9

R49

0R

S2

R31

NM

C76

100p

F08

05

SOT2

3TS

2431

-AIL

T

2010

1


AN5207 - Rev 2 page 30/47

5 Bill of materials

Table 8. STEVAL-POE005V1 bill of materials

Item Q.ty Ref. Part/Value Description Manufacturer Order code

1 4 C1, C2, C3, C4 10 nF 250 VC0805 Capacitors Wurth

Elektronik 885342207010

2 1 C5 2.2 nF 2KVC1812 Capacitor AVX

3 4 C6, C7, C8, C9 1 nF 2KVC1812

Capacitors (notmounted) TDK

4 1 C10 1 nF 2KVC1812 Capacitor AVX

5 2 C11, C12 1 nF 250 VC0805 Capacitors Wurth


6 2 C13, C17 100 nF 100 VC0805 Capacitor Wurth


7 1 C14 10 nF 100 VC0603 Capacitor Wurth


8 1 C15 33 µF 100 V C-POL8-10 Capacitor Panasonic EEEFK2A330P

9 2 C16, C24 4.7 µF 100 VC1210 Capacitor TDK

10 1 C18 1.5 nF 100 VC0603 Capacitor Wurth




12 2 C20, C22 2200 pF 2KVC1812

Capacitors (notmounted) AVX

13 1 C21 2200 pF 2KVC1812 Capacitor AVX

14 5 C23, C26, C46,C51, C95

1 nF 100 VC0805 Capacitor Wurth


15 1 C25 100nF 25VC0603 Capacitor Wurth


16 3 C27, C28, C30 100 V C0805 Capacitors (notmounted) Any

17 1 C29 33 µF 100 V C-POL8-10

AluminiumElectrolyticcapacitor

Panasonic EEEFK2A330P

18 3 C31, C32, C33 4.7uF 100VC1210 Capacitors TDK


20 1 C35 2200 pF 2KVC1812

Capacitor (notmounted) AVX

21 3 C36, C37, C38 47 µF 16 VC1210 Capacitor Wurth


22 1 C39 1 nF 100 VC0805

Capacitor (notmounted)

WurthElektronik 885012207116

AN5207Bill of materials

AN5207 - Rev 2 page 31/47


23 3 C40, C41, C42 47 µF 16 VC1210

Capacitor (notmounted)


24 1 C43 100 0F 16 VCase D

AluminiumElectrolyticcapacitor

Panasonic EEEFK1C101P

25 2 C44, C45 100 nF 25 VC0603 Capacitor Wurth


27 1 C47 2.2 µF 25 VC0603 Capacitor Any

28 1 C48 47 nF 200 VC1206 Capacitor Any

29 1 C49 200 V C1206 Capacitor (notmounted) Any

30 3 C50, C55, C58 100 nF 25 VC0603 Capacitor Wurth


31 1 C52 100 pF 25 VC0603 Capacitor Any




34 1 C56 C0603 Capacitor (notmounted) Any

35 1 C57 22 nF COG 25V C0603

Capacitor (notmounted) Any

36 1 C59 220 pF COG 25V C0603 Capacitor Wurth


37 1 C60 22 nF COG 25V C0603 Capacitor Any

38 4 C61, C62, C63,C64

33 nF 100 VC0805 Capacitor Wurth


39 2 C75, C76 100 pF 50 VC0805 Capacitor Wurth





42 3 C82, C83, C84 1 nF 25 VC0603 Capacitor Wurth


43 1 C85 20 K R0805 Resistor (notmounted) Any


45 8C87, C88, C89,C90, C91, C92,

C93, C94

10 nF 1KVC1210

Capacitor (notmounted) AVX 1210AC103KAT

1A

46 1 C96 2.2 µF 25 VC0603 Capacitor Any

47 1 C97 47K R0603 Resistor Any

48 1 C98 47K R0603 Resistor Any


AN5207 - Rev 2 page 32/47


49 1 D1 SOD-323 Diode Any

50 1 D2 SOD-23 Diode Any

51 1 D3 SOT23 Diode Any

52 1 D4 T2 LED Diode Kingbright AA3528CGSK



55 1 D7 SMA Diode TVS ST SMAJ58A

56 1 D8 SMA Transil Diode ST

57 1 D9 SOD-323 Diode Any BAS16J

58 1 D11 SOT23-D Zener diode(not mounted) Any BZX84C10

59 15

D12, D13, D14,D16, D17, D20,D37, D43, D45,D46, D47, D48,D49, D50, D51

SOD-323 Diode Any

60 1 D15VOUT Led

LED_SMD_0805

LED Diode Several

61 1 D39 FAUX LED Diode Kingbright AA3528CGSK

62 1 D40 STBY LED Diode Kingbright AA3528CGSK

63 2 D41, D42 SMC Diode ST STPS4S200S

64 1 D44 RAUX LED Diode Kingbright AA3528CGSK

65 2 D52, D53 SOT-23Dual DiodeCommonAnodes

Any BAS70-05

66 1 J1DATA &

POWER INPUTRJ45-8PIN

Connector Bell Stewart SS-7188S-A-NF

67 1 J2 DATA OUTPUTRJ45-8PIN Connector Bell Stewart SS-7188S-A-NF

68 2 J4, J6 BANANA-JACKBOC_10A Connector Any

69 1 J9 AUX Front Power Jack Switchcraft P-JACK-RAPC722

70 1 J10 AUX Rear Power Jack Switchcraft P-JACK-RAPC722

71 1 L1POWER

INDUCTOR, 5.6µH

InductorWurth


Coilcraft XAL5050-562

72 2 L2, L3 220 R 805Inductor (not

mounted, mountohm resistor)

TDK MPZ2012S221AT000

73 1 L4 10 µH Inductor WurthElektronik 7443631000

74 4 L5, L6, L7, L8 220 R 805 Ferrite beads TDK MPZ2012S221AT000

75 1 L9 Low ProfilePower inductor Coilcraft LPS4018-105M

L


AN5207 - Rev 2 page 33/47


76 1 P1 SLEEP/WKUP Push Button Any

77 1 P2 SHDN Push Button Any

78 2 Q1, Q5 POWERFLAT_5X6_SGD Power MOSFET ST STL90N6F7

79 1 Q2 POWERFLAT_5X6_SGD

Power MOSFET(not mounted) ST STL90N6F7

80 2 Q3, Q8 MMBT3904LT1SOT23_BEC_T

Switchingtransistor NPN(not mounted)

Any MMBT3904LT1

81 1 Q4

BSC190N15NS3

POWERFLAT_5X6_SGD

Power MOSFET Infineon BSC190N15NS3

82 1 Q7 POWERFLAT_3X3_SGD

SwitchingMOSFET P

channelAny FDMC86259P

83 2 Q9, Q12 SOT23_BEC_T Switchingtransistor NPN Any PBSS4240T

84 2 Q10, Q11 SOT23_BEC_TSwitching

transistor PNP(not mounted)

Any PBSS5240T

85 2 Q13, Q14 SOT23 N channelMOSFET Any 2N7002

86 8 R1, R2, R3, R4,R5, R6, R7, R8 75 R R0603 Resistor Any

87 1 R9 0R0 R1210 Resistor Any

88 1 R14 26.1 K ±1%R0603 Resistor Any

89 1 R15 R1206 Resistor (notmounted) Any

90 1 R16 5R6 R0805 Resistor (notmounted) Any

91 1 R17 22 R R0805 Resistor Any

92 3 R18, R19, R20 3.9 K R0603 Resistor Any

93 2 R21, R30 10 K R0805 Resistor (notmounted) Any

94 1 R22 51R1 ±1%R0805 Resistor Any

95 1 R23 36R5 ±1%R0805 Resistor Any

96 2 R24, R26 0R0 R1206 Resistor Any

97 3 R25, R37, R40 10 K R0603 Resistor Any

98 1 R27 3Mega R2010 Resistor (notmounted) Any

99 1 R28 0R R0603 Resistor Any

100 1 R29 1 K R0805 Resistor Any



AN5207 - Rev 2 page 34/47

http://www.st.com/en/product/STL90N6F7


102 1 R32 10 R R0805 Resistor (notmounted) Any



105 2 R35, R75 1 K R0805 Resistor Any

106 2 R36, R38 10 R R0805 Resistor Any


108 1 R43 130 K ±1%R0603 Resistor Any

109 1 R44 R050 ±1%R1210 Resistor Any

110 1 R45 330 K ±1%R0603 Resistor Any

111 1 R46 91 K ±1%R0603 Resistor Any


113 1 R48 0R ±1% R0603 Resistor Any


115 1 R50 390 R ±1%R0603 Resistor Any

116 1 R51 2 K ±1% R0603 Resistor Any

117 1 R52 20 k ±1%R0603 Resistor Any

118 1 R53 4.7 K ±1%R0603 Resistor Any

119 1 R54 4K64 ±1%R0603

Resistor (notmounted) Any

120 1 R55 5K23 ±1%R0603 Resistor Any


122 5 R57, R58, R59,R60, R67 0R0 R0805 Resistor (not

mounted) Any


124 1 R62 5K6 R0805 Resistor (notmounted) Any

125 1 R69 100 k R0805 Resistor Any

126 2 R76, R77 0R R0805 Resistor Any

127 1 R78 0R R1206 Resistor Any

128 1 R101 ±1% R0603 Resistor (notmounted) Any


130 1 R103 12k ±1% R0603 Resistor Any

131 1 R104 56K ±1% R0603 Resistor Any



AN5207 - Rev 2 page 35/47



134 1 R108 R100 R1210 Resistor Any

135 1 R114 4K7 R0805 Resistor Any

136 2 R115, R116 100 k R0805 Resistor Any

137 1 R117 4k7 R0805 Resistor Any

138 1 R118 0 R R0805 Resistor (notmounted) Any

139 1 R119 100 k R0603 Resistor (notmounted) Any

140 1 R120 4k3 R0805 Resistor Any



143 1 R123 1 k R0805 Resistor Any



146 1 R126 10 R0603 Resistor Any







153 1 R133 100K R0603 Resistor Any

154 2 RV1, RV2 1812 Surge arrester(not mounted) TDK B88069X9231T

203

155 1 T1 POE Trafo Data TrafoWurth


Coilcraft WA8704-ALD

156 1 T2 RN112 Common Choke(not mounted) Schaffner RN

112-4-02-0M7

157 1 T3 750370225 Rev03 Power Trafo Wurth

Elektronik

158 1 T4Planar Power

Trafo (notmounted)

Coilcraft

159 2 T5, T6 WURTH_WE-SL5

Common Choke(not mounted)


160 2 T7, T8 RN102 Common Choke Schaffner RN102-2-02-1M1


AN5207 - Rev 2 page 36/47


161 14

TP1, TP3, TP5,TP7, TP8,

TP12, TP13,TP14, TP15,TP16, TP17,TP18, TP19,

TP20

KEYSTONE_5010 Test point red Any

162 4 TP2, TP4, TP6,TP9

KEYSTONE_5011 Test point black Any

163 2 TP10, TP11 MILLMAX_2501 Test point turret Any

164 1 U1 QFN56-8X8X1-49PIN Controller ST PM8805

165 1 U2 16QFN_3X3X0.75_0.5 Controller ST PM8804

166 1 U3 FOD817 Optocoupler Fairchild FOD817AS

167 2 U4, U23 SOT-23-5LEADVoltage

Reference (notmounted)

ST TS431AILT

168 5 U5, U16, U17,U18, U19

Diode TVSSMC Transil Any

169 5 U6, U7, U8, U9,U11

Diode TVSSMC

Transil (notmounted) Any

170 1 U10 Diode TVSSMC Transil ST SM15T68CA

171 2 U12, U24 SOT-23-3L VoltageReference ST TS2431-AILT

172 2 U20, U21 Diode TVSSMC

Transil (notmounted) Any

173 1 U22 FOD817 Optocoupler Fairchild FOD817AS


AN5207 - Rev 2 page 37/47

http://www.st.com/en/product/pm8805

http://www.st.com/en/product/pm8804

http://www.st.com/en/product/ts431

http://www.st.com/en/product/sm15t

http://www.st.com/en/product/ts2431

6 Board layout

Figure 30. STEVAL-POE005V1 reference design PCB top assembly

Figure 31. STEVAL-POE005V1 reference design PCB bottom assembly

AN5207Board layout

AN5207 - Rev 2 page 38/47

Figure 32. STEVAL-POE005V1 reference design PCB layer 1 top

Figure 33. STEVAL-POE005V1 reference design PCB layer 2

AN5207Board layout

AN5207 - Rev 2 page 39/47



AN5207Board layout

AN5207 - Rev 2 page 40/47



AN5207Board layout

AN5207 - Rev 2 page 41/47

A ReferencesFreely available on www.st.com:1. PM8804 datasheet2. PM8805 datasheet

AN5207References

AN5207 - Rev 2 page 42/47



Revision history

Table 9. Document revision history

Date Version Changes

05-Oct-2018 1 Initial release.

09-May-2019 2

Updated title, Introduction,Figure 1. STEVAL-POE005V1 referencedesign and Figure 2. STEVAL-POE005V1 reference design:component view.

AN5207

AN5207 - Rev 2 page 43/47

Contents

1 STEVAL-POE005V1 reference design overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

1.1 Specifications, connectors and LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 Board setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

2.1 PM8805 configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 PoE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.3 FAUX connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.4 RAUX with MPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.5 Soft stop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 Measurements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

3.1 Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.2 Output voltage ripple. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.3 Input voltage ripple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.4 Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.5 PoE connector unplugged power off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

3.6 Primary side waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.7 Secondary side waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

3.8 Load transient side waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3.9 Gloop measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

3.10 Board thermography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4 STEVAL-POE005V1 schematic diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

5 Bill of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

6 Board layout. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

A References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

AN5207Contents

AN5207 - Rev 2 page 44/47

List of figuresFigure 1. STEVAL-POE005V1 reference design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Figure 2. STEVAL-POE005V1 reference design: component view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Figure 3. PSE to RAUX switchover at VPSE=55 V, VRAUX=48 V, IOUT=5.5 A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Figure 4. RAUX to PSE switchover at IOUT=5.5 A, VRAUX=48 V, PSE voltage=55 V. . . . . . . . . . . . . . . . . . . . . . . . . . . 8Figure 5. RAUX to PSE switchover at IOUT=5.5 A, Aux Rear = 44 V, PD voltage = 55 V. . . . . . . . . . . . . . . . . . . . . . . . . 9Figure 6. STEVAL-POE005V1 overall and DC-DC forward efficiency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Figure 7. Output voltage ripple: IOUT= 800 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Figure 8. Output voltage ripple: IOUT= 8 A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Figure 9. Input voltage ripple before and after forward input filter: VIN = 48 V, IOUT = 800 mA . . . . . . . . . . . . . . . . . . . . 13Figure 10. Input voltage ripple before and after forward input filter: VIN = 48 V, IOUT = 8 A . . . . . . . . . . . . . . . . . . . . . . . 14Figure 11. Output voltage at startup: Iout at no load, Vin= 48 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Figure 12. Output voltage at startup: Iout=8 A, Vin= 48 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Figure 13. Power off at primary side: Iout=8 A, Vin= 42 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Figure 14. Power off at secondary side (Q1): Iout=8 A, Vin= 42 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Figure 15. Power off at secondary side (Q5): Iout=8 A, Vin= 42 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure 16. Primary steady state: Iout=800 mA, Vin= 48 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Figure 17. Primary steady state: Iout=8 A, Vin= 48 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Figure 18. Secondary steady state: Iout=800 mA, Vin= 48 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Figure 19. Secondary steady state: Iout=8 A, Vin= 48 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Figure 20. Load transient: Iout=4 to 8 A, Vin= 48 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Figure 21. Gloop plot (Vin= 48 V, Iout=6 A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Figure 22. Gloop plot (Vin= 48 V, Iout=0.8 A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Figure 23. Gloop plot (Vin= 42 V, Iout=6 A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Figure 24. Gloop plot (Vin= 42 V, Iout=0.8 A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Figure 25. STEVAL-POE005V1 reference design thermography at 8 A, 56 V (emissivity = 0.95, reflected temperature = 20°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Figure 26. STEVAL-POE003V1 reference design thermography at 6 A, 41 V (emissivity = 0.95, reflected temperature = 20°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Figure 27. STEVAL-POE005V1 circuit schematic (1 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Figure 28. STEVAL-POE005V1 circuit schematic (2 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Figure 29. STEVAL-POE005V1 circuit schematic (3 of 3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Figure 30. STEVAL-POE005V1 reference design PCB top assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Figure 31. STEVAL-POE005V1 reference design PCB bottom assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Figure 32. STEVAL-POE005V1 reference design PCB layer 1 top . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Figure 33. STEVAL-POE005V1 reference design PCB layer 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Figure 34. STEVAL-POE005V1 reference design PCB layer 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Figure 35. STEVAL-POE005V1 reference design PCB layer 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Figure 36. STEVAL-POE005V1 reference design PCB layer 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Figure 37. STEVAL-POE005V1 reference design PCB layer 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

AN5207List of figures

AN5207 - Rev 2 page 45/47

List of tablesTable 1. STEVAL-POE005V1 specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Table 2. STEVAL-POE005V1 connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Table 3. STEVAL-POE005V1 LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Table 4. Tx signal possible configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Table 5. PM8805 control signal description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Table 6. PM8805 class description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Table 7. PM8805 PD main parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Table 8. STEVAL-POE005V1 bill of materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Table 9. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

AN5207List of tables

AN5207 - Rev 2 page 46/47

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AN5207

AN5207 - Rev 2 page 47/47

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