KS8995E Micrel Inc, KS8995E Datasheet - Page 40

• Manufacturer Part Number: KS8995E
• Manufacturer: Micrel Inc

Specifications of KS8995E

• Number Of Primary Switch Ports: 5
• Fiber Support: Yes
• Integrated Led Drivers: Yes
• Phy/transceiver Interface: MII/SNI
• Power Supply Type: Analog/Digital
• Package Type: PQFP
• Data Rate (typ): 10/100Mbps
• Vlan Support: Yes
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Pin Count: 128
• Mounting: Surface Mount
• Jtag Support: No
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Not Compliant

KS8995E
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.
KS8995E
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.)
Jitter (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.
Value
1 CT : 1 CT
350 H
0.4 H
12pF
0.9
1.0dB
1500Vrms
Value
25.00000
150
100
(Note 1)
40
Test Condition
100mV, 100KHz, 8mA
1MHz (min.)
0MHz to 65MHz
Units
MHz
ppm
ps(pk-pk)
August 2003
Micrel