KS8721B TR Micrel Inc, KS8721B TR Datasheet - Page 30

• Manufacturer Part Number: KS8721B TR
• Description: IC TXRX PHY 10/100 2.5V 48SSOP
• Manufacturer: Micrel Inc
• Type: Transceiverr

Specifications of KS8721B TR

• Number Of Drivers/receivers: 1/1
• Protocol: MII, RMII
• Voltage - Supply: 2.375 V ~ 2.625 V
• Mounting Type: Surface Mount
• Package / Case: 48-SSOP
• For Use With: 576-1006 - BOARD EVAL EXPERIMENT KS8721B
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: KS8721BTR

KS8721B/BT
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.
Note 1.
Selection of Reference Crystal
An oscillator or crystal with the following typical characteristics is recommended.
M9999-041405
Single Port
Magnetic Manufacturer
Pulse
Bel Fuse
YCL
Transpower
Delta
LanKom
Integrated Transformers
Pulse
Pulse
Characteristics Name
Turns Ratio
Open-Circuit Inductance (min.)
Leakage Inductance (max.)
Inter-Winding Capacitance (max.)
D.C. Resistance (max.)
Insertion Loss (max.)
HIPOT (min.)
Characteristics Name
Frequency
Frequency Tolerance (max.)
Load Capacitance (max.)
Series Resistance (max.)
The IEEE 802.3u standard for 100BaseTX assumes a transformer loss of 0.5dB. For the transmit line transformer, insertion loss of up to
1.3dB can be compensated by increasing the line drive current by means of reducing the ISET resistor value.
Part Number
H1102
S558-5999-U7
PT163020
HB726
LF8505
LF-H41S
J0011D21
J00-0061
Value
1 CT : 1 CT
350µH
0.4µH
12pF
0.9Ω
1.0dB
1500Vrms
Value
25.00000
±100
20
40
Table 8. Qualified Transformer Lists
(Note 1)
30
Test Condition
100mV, 100 KHz, 8 mA
1MHz (min.)
0MHz to 65MHz
Units
MHz
ppm
pF
Ω
Auto MDIX
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Number
of Ports
1
1
1
1
1
1
1
1
Micrel, Inc.
April 2005