1. POE (Power Over Ethernet)
SGYOON / Sr.Applications Engineer and SJ Kuen apps engineer 29th, May – 2009 updated Mike speed 12th November 2010

2. Contents. What is POE? Suppliers Analysis
Fairchild’s Value and Portfolio

3. What is POE?

4. What is POE?
A system to transfer electrical power, along with data, to remote devices over standard twisted-pair cable(CAT-5) in an Ethernet network  AC power is not required.
Configuration : PSE(Power Sourcing Equipment), PD(Power Device)
Standard : IEEE 802.3af(Started from 2003), IEEE 802.3at(Started from 2004)
IP phone
Wireless LAN Access point
Security Camera
PCs
Midspan
(Power integrated)
PD : Terminal (IP phone, Wirelss Lan port)
PSE : END span, Mid span (Ethernet switch)

5. POE Advantages

6. POE Standards IEEE 802.3af (POE) device power : up to 12.95W
IEEE 802.3at (POE+) device power : up to 60W
PSE : Power source, Ethernet Routers, Switches and Hubs.
PD : VoIP Phones, Wireless LAN Access points, IP Cameras.
VoIP
Wireless LAN
ETC..
PSE Power supply
PSE Circuit
CAT5 Cable
PD Circuit

7. POE vs. POE+ POE IEEE 802.3af POE+ IEEE 802.3at PSE Output voltage
44V ~ 57V
50V ~ 57V
CAT5 Max current on 2-pairs
Under 45degC cable temp
350mA ~ 400mA
720mA
PD Power Level
Max 12.95W
Min 30W ~ Max 60W
CAT 5 Cable pairs
2-pairs
(PSW power : 15.4W, PD power :12.95W)
(PSE power : 36W, PD power : 29.5W)
4-pairs
(PSE power : 72W, PD power 59W)
Detection
25kohm
Classification
Class4
2-Event Classification
Layer-2 Cassification
Etc
Up to 1Gbyte Midspan
Support for 10Giga byte Midspan(IEEE 802.3an)
Pan –Zoom –Tilt 카메라, 멀티미디어 키오스트, 인더스트리얼 건트롤러, 랩탑 배터리 충청기

8. What is PSE? PSE – Power Sourcing Equipment
The PSE is the equipment that provides power to PDs. The PSE’s main functions are:
To search the link section for a PD.
Optionally classify the PD.
Supply power to the link section. (only if a PD is detected)
Monitor the power on the link section.
802.3af defines two types of power source equipment: Endspan and Midspan.
Endspan refers to an Ethernet switch with embedded Power over Ethernet technology.
Midspan devices are usually placed between legacy switches and the powered devices.

9. Configurations
Midspan is resides between the Switch and the PD, providing power only.
Endspan configuration integrates POE into Switch

10. What is PD? PD – Powered Device
A PD is a device that is either drawing power or requesting power from PSE.
The Power Class of PD:
Once a PD is discovered, a PSE may optionally perform PD classification by applying a DC voltage and current to the port, allocated power is subtracted from total power budget.
Any unclassified PD is considered to be a class 0 device.
Class 3 is similar to Class 0 in that it also requests full power, but a Class 3 PD will always draw at least 7W according to the standard, whereas a Class 0 device could draw anything up to full power
PD Device is referring to the device like:
PoE IP-Cam (5~12W), PoE IP-Phone (3~6W), PoE Wi-Fi access point (4~11W), PoE RFID Reader, PoE door controller, PoE printer server….etc

11. POE (IEEE 802.3af ) Applications example
PSE : Convert from AC voltage(110V ~ 240V) to 44V ~ 57V.
Transmission : CAT5 Cable, Max 100m distance.
PD : Input(37 ~ 57V), Convert to 5V, 3.3V, 2.5V, 1.2V, 0.9V using DC/DC.
PSE PD
Ethernet switch
POE Midspan
44~57VDC
Max 350mA/port
15.4W
CAT5 Cable -100m
Network Camera
10~12W
Wireless LAN Access
6~12W
VoIP Phone
3~5W
Power
Max 12.95W

12. Cable connection(CAT5 Cable)
PD should operate with both schemes for success in market.
POE system must allow the non-powered device to access.
Power supplied over the Spare pins
(Midspan configuration)
Power supplied over the Data pins
(Endspan configuration)
Power sourced through SPARE pairs.
Pins 4 and 5 connected together and forming the positive supply
Pins 7 and 8 connected together and forming the negative supply
Power sourced through DATA transfer center tap
The pair on pins 3 and 6, the pair on pins 1 and 2 can be of either polarity.

13. Suppliers Analysis

14. LTC solutions
LTC has PSE power solutions, PD interface controllers and F/B controllers.
PSE power source controller
LTC4258, LTC4263, LTC4259A
PD interface controller
LTC4264/5, LTC4267/8, LTC4257
F/B controller
LT1725, LTC1871, LTC3803, LT3825, LT3837, LTC3805/6, LTC4267/8, LTC3887

15. MicroSemi Ev.Board Analysis
Interface block
F/B block
2’nd filtering block
Detection, Classification, Isolation
FlyBack conversion
DC/DC Conversion PD
0.75A 1A 1A

16. Application Example Circuit Conditions EVB Vehicle / Schematics
Descriptions
Evaluation Board
LT3825 PoE board
Controller
LT3825
Topology
Flyback
Primary Switch
FDS86242
FDC86244
FDN86246
Secondary Switch
FDS8880
VIN
47V
V Gate
7.4V VO 5V
Switching frequency
250kHz
Maximum load current 3A
Transformer
EPC2018
Running Condition
0.5,1,1.5….3A
5min. soaking/each step

17. Summary & Conclusion Analysis
For primary switch in flyback converter, the cross reference test of FDS86242, FDC86244 and FDN was measured.
In middle load, the lowest Qg value of FDN86246 made the total efficiency highest but the gap of efficiency between FDN86246 and FDC86244 was reduced as increased load due to higher Rds(on) of FDN86246.
Because of higher Qg value of FDS86242, FDS86242 had the biggest power loss.
The temperature of FDN86246 was highest due to higher Rthjc in spite of the lowest power loss.
Conclusions
FDC86244&FDN86246 are the good solution for IEEE802.3af in aspect of the efficiency and thermal performance and also the smaller package size has the merit to design PCB size.
To apply FDS86242 to IEEE802.3at for primary switch, it is better to reduce Qg value of FDS86242 to increase the efficiency.
Power
Application
Package
Item
IEEE802.3af
3.8W
Primary
SSOT23
FDN86246
15W
SSOT6
FDC86244
Secondary -
IEEE802.3at
28W
SOT6
SO8
FDS86242
IEEE802.3at+
60W
FDS8880

18. Efficiency & Power loss
Analysis
Because the switching performance of FDN86246 is better, the efficiency of FDN86246 is higher about 0.2~ 0.3% at middle load than FDC86244.
In middle load, the lowest Qg value of FDN86246 made the total efficiency highest but the gap of efficiency between FDN86246 and FDC86244 was reduced as increased load due to higher Rds(on).
Because of higher Qg value of FDS86242, FDS86242 had the biggest power loss.

19. IR Thermal data Temperature @ 5Vo/3A FDS86242 44.4℃ FDC86244 42.4℃
Vin = 47V, Vout = 5V/Iout=Max. 3A ( At the room temperature)
FDS86242
FDC86244
Active bridge FET
Active bridge FET
FDS8880
FDS8880
FDS86242
FDC86244
FDN86246
5Vo/3A
FDS86242
44.4℃
FDC86244
42.4℃
FDN86246
47.7℃
Active bridge FET
FDS8880
FDN86246

20. PT5 150V Release 2010 Package Part Number VGS(V) RDS(ON) Max (mΩ) @10V
Next gen of..
ID (A)
QG (nC)
QGD (nC)
Samples
DPAK
FDD86250 20
TBD
FDD2572
P11-10
Power 56
FDMS86200 18
FDMS2572+
9.6 33
7.7
Released
Dual Cool 56
FDMS86200DC
16.5 -
Q1-10
FDMS86252 46
FDMS2572 11
Power33
FDMC86240
FDMC
Dual Cool 33
FDMC86240DC 45
Q2-10
SO8
FDS86240 16
FDS2572 32
FDS86242 60
FDS2582
FDS86248
100
N/A
P12-10
Power 33
FDMC86244
150
Si7818DN 4 1
SSOT6
FDC86244
FDC2512
2.2
SSOT3
FDN86246
250

21. POE Enabled Products
NEW Cisco Cius Tablet

22. CCI Strategy
Align with the PSE and where appropriate the PD controller
Players to offer FET solutions targetted for POE
Target partners
LTC - closest partner with NDA signed
Maxim - communication and meetings .
Microsemi - meetings and close co-operation in Asia
Ti – some alignment wary of Ciclon acqusition
Silicon Labs – emerging supplier to Cisco

23. FET’s for Isolated DC-DC Converter for POE
200V Primary for Flyback
Package
Part Number
VGS(V)
RDS(ON) Max Qg
ID (A)
Main attribute
Status
SO8
FDS2672 20 70
33nC
3.9
value
Released
MLP 3x3
FDMC2610
200
12.3nC
2.2
Small size
Power 56
FDMS2672 77
30nC
3.7
Better
thermal
150V Primary for Flyback/Forward
Package
Part Number
VGS(V)
RDS(ON) Max Qg
ID (A)
Main attribute
Next Gen
Status
Samples
SO8
FDS86242 20 67
8.9nC
4.1
803.3at+
Class 4
FDS2582
Released
Yes
SSOT6
FDC86244
146
4nC
2.2
802.3af
Class 3
FDC2512
P11-10
SSOT3
FDN86246
261
2.4nC
1.6
Class 1 - No
30V Secondary Synchronous rectifier for 12V, 5V and 3V3 output
Package
Part Number
VGS(V)
RDS(ON) Max Qg
ID (A)
Main attribute
Status
SO-8
FDS8880 20 10
23nC
11.6
30V for 3V3 output
Released
FDS86141 23
12nC 7
100V for12V output
SO8
FDS5672
34nC 12
60V for 5V output

24. PoETec Application PoETec is a consortium of manufacturers
Chipmakers - Ti, Maxim, LTC etc
Connectors/magnetics - Belfuse, Pulse, Molex etc
Network equipment makers - HP Procurve

25. POE FET solutions for PSE Side
Wide SOA
Rugged design tested in Application
Industry standard footprints
100V PSE
Package
Part Number
VGS(V)
RDS(ON) Max
ID (A)
Main attribute
Status
MLP 3x3
FDMC3612 20
110
3.3
Small Size
Released
Yes
SO-8
FDS86106
105
3.4
Value
P10-09
yes
SOT223
FDT3612
120
3.7
Legacy

26. PoETec PSE Boards both 12 Port
Legacy SOT223
Emerging Power 33

27. PSE power capability of FDT3612

28. Common Footprint Land pattern
SOT223
Power 33

29. Rdson vs. Bvdss
Standard
Trench
Shielded
Gate

30. Section 2: Key Parameters - Rdson
Comparing the contribution percentage of each of the series resistances for a low voltage part and a high voltage part we would see the following: (silicon only)
It is obvious from this table that most of the work being done today on high voltage MOSFETs is geared towards reducing the drift (EPI) region resistance.
Rds(on)
Vds = 30V
Vds = 100V
Rs = 2%
Rs = 5%
RN = 3%
RN+ = 10%
RCHAN = 36%
RCHAN = 15%
REPI = 30%
REPI = 60%
RSUB = 29%
RSUB = 10%
Note: Planar MOSFETs also have an
additional component that trench
MOSFETs do not have:
- JFET resistance (RJFET)

31. THANKYOU! Questions? Requests?
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32. The Right Technology for Your Success™
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