KS8997 Micrel Inc, KS8997 Datasheet - Page 37

• Manufacturer Part Number: KS8997
• Description: IC SWITCH 10/100 8PORT 128PQFP
• Manufacturer: Micrel Inc

Specifications of KS8997

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 128-MQFP, 128-PQFP
• Fiber Support: No
• Integrated Led Drivers: Yes
• Phy/transceiver Interface: MII
• 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: Contains lead / RoHS non-compliant

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. 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
Selection of Reference Oscillator/Crystal
An oscillator or crystal with the following typical characteristics is recommended.
The following transformer vendors provide compatible magnetic parts for Micrel’s device:
February 2007
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
Maximum Frequency Tolerance
Maximum Jitter
Type
Transformer only
can be compensated by increasing the line drive current by means of reducing the ISET resistor value.
Vendor
Pulse
4-Port Integrated
Value
1 CT : 1 CT
350µH
0.4µH
12pF
0.9Ω
1.0dB
1500Vrms
Value
25.00000
±100
150
Table 8. Qualified Magnetics Lists
(1)
H1164
Part
37
Test Condition
100mV, 100 KHz, 8mA
1MHz (min.)
0MHz to 65MHz
Test Condition
MHz
ppm
ps(pk-pk)
Vendor
Pulse
Single-Port
M9999-022807-1.1
H1102
Part