KS8995MI Micrel Inc, KS8995MI Datasheet - Page 23
![IC SWITCH 10/100 5PORT 128PQFP](/photos/6/81/68152/576-128-pqfp_sml.jpg)
KS8995MI
Manufacturer Part Number
KS8995MI
Description
IC SWITCH 10/100 5PORT 128PQFP
Manufacturer
Micrel Inc
Specifications of KS8995MI
Applications
*
Mounting Type
Surface Mount
Package / Case
128-MQFP, 128-PQFP
Number Of Primary Switch Ports
5
Internal Memory Buffer Size
64
Operating Supply Voltage (typ)
1.8/2.5/3.3V
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)
85C
Operating Temperature (min)
-40C
Pin Count
128
Mounting
Surface Mount
Jtag Support
No
Operating Supply Voltage (max)
1.9/2.6/3.6V
Operating Supply Voltage (min)
1.7/2.4/3V
Operating Temperature Classification
Industrial
Data Rate
100Mbps
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
For Use With
576-1017 - BOARD EVAL EXPERIMENT KS8995M
Lead Free Status / RoHS Status
Not Compliant, Contains lead / RoHS non-compliant
Other names
576-1020
Available stocks
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Part Number
Manufacturer
Quantity
Price
detect, and FXSDx ‘L’ is below the 1.25V reference to indicate no signal. When FXSDx is below 0.6V then 100BaseFX mode
is disabled. Since there is no auto-negotiation for 100BaseFX mode, ports 4 and 5 must be forced to either full or half-duplex.
Note that strap in options exist to set duplex mode for port 4, but not for port 5.
100BaseFX Far End Fault
Far end fault occurs when the signal detection is logically false from the receive fiber module. When this occurs, the
transmission side signals the other end of the link by sending 84 1s followed by a zero in the idle period between frames. The
far end fault may be disabled through register settings.
10BaseT Transmit
The output 10BaseT driver is incorporated into the 100BaseT driver to allow transmission with the same magnetics. They are
internally wave-shaped and pre-emphasized into outputs with a typical 2.3V amplitude. The harmonic contents are at least
27dB below the fundamental when driven by an all-ones Manchester-encoded signal.
10BaseT Receive
On the receive side, input buffer and level detecting squelch circuits are employed. A differential input receiver circuit and a
PLL perform the decoding function. The Manchester-encoded data stream is separated into clock signal and NRZ data. A
squelch circuit rejects signals with levels less than 400mV or with short pulse widths in order to prevent noises at the RXP or
RXM input from falsely triggering the decoder. When the input exceeds the squelch limit, the PLL locks onto the incoming signal
and the KS8995M decodes a data frame. The receiver clock is maintained active during idle periods in between data reception.
Power Management
The KS8995M features a per port power down mode. To save power the user can power down ports that are not in use by setting
port control registers or MII control registers. In addition, it also supports full chip power down mode. When activated, the entire
chip will be shut down.
MDI/MDI-X Auto Crossover
The KS8995M 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 crossover feature may be disabled through the port control
registers.
Auto-Negotiation
The KS8995M 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 KS8995M 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 in Figure 4.
December 2003
KS8995M
Start Auto Negotiation
Force Link Setting
and Set Link Mode
Auto-Negotiation
Bypass
Yes
Figure 4. Auto-Negotiation
Auto-Negotiation
Attempt
No
23
Listen for 100BaseTX
Link Mode Set ?
Link Mode Set
Operation
Join Flow
Parallel
Idles
Yes
Listen for 10BaseT
Link Pulses
No
M9999-120403
Micrel