KS8721B Micrel Inc, KS8721B Datasheet - Page 30
![Special Function IC](/photos/6/84/68448/576-48-ssop_sml.jpg)
KS8721B
Manufacturer Part Number
KS8721B
Description
Special Function IC
Manufacturer
Micrel Inc
Type
Transceiverr
Specifications of KS8721B
Peak Reflow Compatible (260 C)
No
Leaded Process Compatible
No
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
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
For Use With
576-1006 - BOARD EVAL EXPERIMENT KS8721B
Lead Free Status / RoHS Status
Not Compliant, Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
KS8721B
Manufacturer:
MICREL/麦瑞
Quantity:
20 000
Part Number:
KS8721BL
Manufacturer:
MICREL/麦瑞
Quantity:
20 000
Company:
Part Number:
KS8721BT
Manufacturer:
LUCENT
Quantity:
560
Part Number:
KS8721BT
Manufacturer:
MICREL/麦瑞
Quantity:
20 000
Part Number:
KS8721BTR
Manufacturer:
MICREL/麦瑞
Quantity:
20 000
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