KS8999 Micrel Inc, KS8999 Datasheet - Page 21

• Manufacturer Part Number: KS8999
• Description: IC SWITCH 10/100 9PORT 208PQFP
• Manufacturer: Micrel Inc

Specifications of KS8999

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 208-MQFP, 208-PQFP
• 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
• Mounting: Surface Mount
• Jtag Support: No
• Operating Temperature Classification: Commercial
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With: 576-1023 - BOARD EVAL EXPERIMENT FOR KS8999
• Lead Free Status / RoHS Status: Not Compliant, Contains lead / RoHS non-compliant

KS8999
Micrel
Power Management
Power Save Mode
The KS8999 will turn off everything except for the Energy Detect and PLL circuits when the cable is not installed on an individual
port basis. In other words, the KS8999 will shutdown most of the internal circuits to save power if there is no link.
MDI/MDI-X Auto Crossover
The KS8999 supports MDI/MDI-X auto crossover. This facilitates the use of either a straight connection CAT-5 cable or a
crossover CAT-5 cable. The auto-sense function will detect remote transmit and receive pairs, and correctly assign the transmit
and receive pairs from the Micrel device. This can be highly useful when end users are unaware of cable types and can also
save on an additional uplink configuration connection.
The auto MDI/MDI-X is achieved by the Micrel device listening for the far end transmission channel and assigning transmit/
receive pairs accordingly. Auto MDI/MDI-X can be disabled by pulling the pin 87 (AUTOMDIX) to low.
Auto-Negotiation
The KS8999 conforms to the auto-negotiation protocol as described by the 802.3 committee. Auto-negotiation allows UTP
(Unshielded Twisted Pair) link partners to select the best common mode of operation. In auto-negotiation the link partners
advertise capabilities across the link to each other. If auto-negotiation is not supported or the link partner to the KS8999 is forced
to bypass auto-negotiation , then the mode is set by observing the signal at the receiver. This is known as parallel mode because
while the transmitter is sending auto-negotiation advertisements, the receiver is listening for advertisements or a fixed signal
protocol.
The flow for the link set up is depicted below.
No
Yes
No
Yes
Figure 2. Auto-Negotiation
January 2005
21
KS8999