Teridian 78Q2120C09, Руководство пользователя

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78Q2120C09
MII Evaluation Board Design Kit
User Manual
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© 2007 Teridian Semiconductor Corporation, Proprietary and Confidential - 3 - Rev_1.2
10/100Mbps Transformer Selection
The line interface for the 78Q2120C09 requires a pair of 1:1 isolation transformers. Integrated common-mode
chokes are recommended for satisfying FCC radiated EMI requirements. Additional filtering is not required with
the 78Q2120C09 due to internal waveform shaping circuitry. The line transformer characteristics are outlined
below:
Name Value Condition
Turns Ratio 1 CT : 1 CT
Open-Circuit Inductance 350 µH (min)
See Note 1.
@ 10 mV, 10 KHz
Leakage Inductance 0.40 µH (max) @ 1 Mhz (min)
Inter-Winding Capacitance 25 pF (max)
D.C. Resistance 0.9 ohm (max)
Insertion Loss 1.1 dB (typ) 0 - 100 Mhz
HIPOT 1500 Vrms
Note 1: The receive line transformer’s Open-Circuit Inductance can be as low as 100 µH for the 78Q2120C09.
The 78Q2120C09 incorporates baseline wander correction circuitry which allows the receiver to track the
incoming data signal when there is excessive transformer droop.
For Commercial Temperature (0
°
C ~ 70
°
C)
Teridian Semiconductor has performed line testing with the following transformers and found their performance
acceptable with the 78Q2120C09:
Manufacturer Part Number
TDK TLA-6T103
Bel-Fuse S558-5999-46
Halo
TG22-3506ND
Pulse PE-68515
Valor ST6118
YCL 20PMT04
The following transformers are low profile packages (0.100 in/2.5 mm or less).
TDK
TLA-6T118
Halo TG110-S050
PCA EPF8023G