78Q2120C Teridian Semiconductor Corp. (TDK Semiconductor), 78Q2120C Datasheet - Page 30

• Manufacturer Part Number: 78Q2120C
• Description: 10/100 Ethernet PHYS
• Manufacturer: Teridian Semiconductor Corp. (TDK Semiconductor)

ISOLATION TRANSFORMERS
Two simple 1:1 isolation transformers are all that are required at the line interface, but transformers with
integrated common-mode choke are recommended for exceeding FCC requirements.
recommended line transformer characteristics:
Note: The 100Base-TX amplitude specifications assume a transformer loss of 0.4 dB. For the transmit line
transformer with higher insertion losses, up to 1.2 dB of insertion loss can be compensated by selecting the
appropriate setting in the Transmit Amplitude Selection bits in register MR19.11:10.
REFERENCE CRYSTAL
If the internal crystal oscillator is to be used, a crystal with the following characteristics should be chosen:
* Equivalent differential capacitance across the XTLP/XTLN pins.
** If crystal with a larger load is used, external shunt capacitors to ground should be added to make up the
equivalent capacitance difference.
© 2003 TDK Semiconductor Corporation, Proprietary and Confidential
Parameters at 25
Temperature Stability ( 0 - 70
Motional Capacitance (min)
Inter-Winding Capacitance
Spurious Response (max)
Shunt Capacitance (max)
Series Resistance (max)
Open-Circuit Inductance
Frequency Tolerance
Leakage Inductance
Load Capacitance*
Oscillation Mode
D.C. Resistance
Insertion Loss
Turns Ratio
Frequency
HIPOT
NAME
NAME
Aging
o
C ± 2
o
C ; Drive Level = 0.5 mW
o
C)
Parallel Resonance, Fundamental Mode
> 5 dB below main within 500 kHz
1 CT : 1 CT ± 5%
0.40 µH (max)
350 µH (min)
12 pF (max)
0.9 Ω (max)
0.4 dB (typ)
1500 Vrms
25.00000
VALUE
VALUE
±50
4**
±2
±5
10
60
- 30 -
8
10/100BASE-TX Transceiver
@ 10 mV, 10 kHz
@ 1 MHz (min)
CONDITION
0 - 65 MHz
PPM/yr
UNITS
This table gives the
PPM
PPM
MHz
pF
pF
f F
Ω
78Q2120C
Rev_1.1