KSZ9021GN TR Micrel Inc, KSZ9021GN TR Datasheet - Page 52

• Manufacturer Part Number: KSZ9021GN TR
• Description: Specifications: Number of Drivers/Receivers: 8/8 ; Type: Transceiver ; Voltage - Supply: 3.135 V ~ 3.465 V ; Package / Case: 64-VFQFN Exposed Pad ; Packaging: Tape & Reel (TR) ; Protocol: Gigabit Ethernet ; Lead Free Status: Lead Free ; RoHS Stat
• Manufacturer: Micrel Inc

Micrel, Inc.
Reference Clock – Connection and Selection
A crystal or external clock source, such as an oscillator, is used to provide the reference clock for the KSZ9021GN. The
reference clock is 25 MHz for all operating modes of the KSZ9021GN.
The following figure and table shows the reference clock connection to XI (pin 61) and XO (pin 60) of the KSZ9021GN,
and the reference clock selection criteria.
Magnetics Specification
A 1:1 isolation transformer is required at the line interface. An isolation transformer with integrated common-mode chokes
is recommended for exceeding FCC requirements.
The following tables provide recommended magnetic characteristics and a list of qualified magnetics for the KSZ9021GN.
September 2010
Characteristics
Frequency
Frequency tolerance (max)
Parameter
Turns ratio
Open-circuit inductance (min.)
Insertion loss (max.)
HIPOT (min.)
Magnetic Manufacturer
Pulse
TDK
Figure 16. 25MHz Crystal / Oscillator Reference Clock Connection
Table 18. Qualified Single Port 10/100/1000 Magnetics
Table 16. Reference Crystal/Clock Selection Criteria
Table 17. Magnetics Selection Criteria
Part Number
H5007NL
TLA-7T101LF
Value
1 CT : 1 CT
350μH
1.0dB
1500Vrms
Value
52
±50
25
Auto MDI-X
Yes
Yes
Test Condition
100mV, 100kHz, 8mA
0MHz – 100MHz
Number of Port
Units
MHz
ppm
1
1
M9999-091010-1.1
KSZ9021GN