E & E Magnetic Products Limited
S
CHEMATICS
Flyback transformers designed for PoE (IEEE802.3af)
powered devices with up to 3 Watts
POWER TRANSFORMER
Flyback Transformer for PoE
Providing Power to PoE devices with up to 3 Watts
Designed for 250kHz switching frequency (continuous mode)
with input of 33 - 57V
Low Leakage Inductance
Hipot voltage: 1500Vrms
Operating temperature -40°C to +85°C.
RoHS compliant version is available
Custom design is also available
E
LECTRICAL
S
PECIFICATION @
25°C
Part
Number
835-00842
835-00843
835-00844
RoHS
Part
Number
835-00842F
835-00843F
835-00844F
Turns Ratio
Pri : Sec
1 : 0.19
1 : 0.28
1 : 0.70
Pri : Bias
1 : 0.70
1 : 0.70
1 : 0.70
Inductance
at 0A
(uH ± 10%)
310
310
310
Inductance Leakage
at Ipk
Inductance
(uH Min)
(nH Max)
279.0
279.0
279.0
4.75
4.50
4.25
DCR
(mOhm Max)
Pri
1020
1020
1040
Bias
2010
2010
2010
Sec
66
118
700
Ipk
(A)
0.3
0.3
0.3
Secondary
Output
Vout=3.3V,0.91A
Vout=5.0V,0.6A
Vout=12V,0.25A
Notes:
1. Inductance is measured at 250kHz, 0.1Vrms, 0Adc.
2. Peak primary current, Ipk, is drawn at minimum input voltage.
3. DCR for the secondary is per winding.
4. Leakage Inductance measured between pins 3 and 4 with all other pins shorted.
5. Turns ratio is with the secondary windings connected in parallel.
6. Output of the secondary is with the windings connected in parallel. Bias winding output is 12V, 20mA.
7.Operating temperature range: -40°
C
to +85°C. The part temperature (ambient temperature + temperature rise)
should not exceed the upper limit of the operating temperature under worst case operating conditions. Circuit design,
component placement, PWB trace size and thickness, airflow and other cooling provisions all affect the part
temperature. Part temperature should be verified in the end application.
2/F Block A, 94 Tokwawan Road, Kowloon, Hong Kong
1
Tel: (852) 2765 3888
Fax: (852) 2954 3304
PX203(01)
Revised in 06/12
E & E Magnetic Products Limited
POWER TRANSFORMER
Flyback Transformer for PoE
Providing Power to PoE devices with up to 3 Watts
M
ECHANICAL
D
IMENSIONS
.090
2.29
.295
7.50
.420 MAX
10.67
1
.520
13.21 MAX
2
3
4
.540
13.72
.098
2.50
EE
5-xxxx
(DATE)
8
7
6
5
.028±.005
0.71±0.13
.052
1.32
RECOMMENDED
PAD LAYOUT
Reference or
Gauge Plane
.010±.005
0.25±0.13
.355 MAX
9.02
0-8°
.098±.010
2.50±0.25
Notes:
.295±.010
7.50±0.25
.040±.010
1.02±0.25
8. All dimensions are specified in
inches
with higher precedence in inches.
mm
9. Unless otherwise specified, all tolerances are ±
.010
.
0.25
10. Coplanarity:
.004
max.
0.10
11. For RoHS compliant version, 835-0yyyyF, the part will be marked with “5-yyyyF”, instead of “5-yyyy”.
Weight (in gram)
Tape & Reel
:
:
2.2 typ.
350 / reel
S
CHEMATICS
3
Pri
4
2
Bias
1
6
5
Sec
7
8
SCHEMATIC
FOR MORE INFORMATION, PLEASE CONTACT
HEADQUARTER
2/F Block A, Merit Industrial Centre,
94 Tokwawan Road, Kowloon,
Hong Kong
Tel: (852) 2765 3888
Fax: (852) 2954 3304
Email: eempl@eleceltek.com
Website: http://www.eleceltek.com
Information herein is for reference only and subject to change without notice. It does not constitute any representation, warranty or commitment of the company in respect
of the products in any aspect. All logos, brands and product names mentioned herein are trademarks or registered trademarks of their respective owners. The company
does not assume any liability arising out of the application or use of any product or circuit described herein. Copyrights 2006, E & E Magnetic Products Limited.
2/F Block A, 94 Tokwawan Road, Kowloon, Hong Kong
2
Tel: (852) 2765 3888
Fax: (852) 2954 3304
PX203(01)
Revised in 06/12
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