MIC2358 Datasheet, PDF (28/29 Pages) Micrel Semiconductor – IEEE 802.3af Octal Power Sourcing Equipment Controller

Micrel, Inc.
MIC2358YLQ
Selection of Isolation Transformer
One simple 1:1 isolation transformer is needed at the line interface. An isolation transformer with integrated common-
mode choke is recommended for exceeding FCC requirements. The following table gives recommended transformer
characteristics.
Characteristics Name
Turns Ratio
Open-Circuit Inductance (min.)
Leakage Inductance (max.)
Inter-Winding Capacitance (max.)
D.C. Resistance (max.)
Insertion Loss (max.)
HIPOT (min.)
Value
1 CT : 1 CT
350µH
0.4µH
12pF
0.9Ω
1.0dB
1500Vrms
Test Condition
100mV, 100kHz, 8mA
1MHz (min.)
0MHz to 65MHz
The following transformer vendors provide compatible PoE magnetic parts for Micrel’s device:
Vendor
Pulse
Part
H2019, H1197
Auto MDIX
Yes
Number of Ports
1
Pulse
H2017
Yes
4
TDK
TAL-6T127LF(-T)
Yes
1
July 2010
28
M9999-070810