KSZ8993MI Micrel Inc, KSZ8993MI Datasheet - Page 23

• Manufacturer Part Number: KSZ8993MI
• Description: IC SWITCH 10/100 W/TXRX 128PQFP
• Manufacturer: Micrel Inc

Specifications of KSZ8993MI

• Applications: *
• Mounting Type: Surface Mount
• Package / Case: 128-MQFP, 128-PQFP
• Number Of Primary Switch Ports: 3
• Internal Memory Buffer Size: 32
• 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): 1.89/3.465V
• Operating Supply Voltage (min): 1.71/3.135V
• Power Dissipation: 800mW
• Supply Current: 0.1/0.19A
• Operating Temperature Classification: Industrial
• Data Rate: 100Mbps
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-2124; KSZ8993MI

10BASE-T Transmit
The output 10BASE-T driver is incorporated into the 100BASE-T driver to allow transmission with the same
magnetic. 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.
10BASE-T Receive
On the receive side, input buffers 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 400 mV 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 KSZ8993M decodes a data frame. The receiver
clock is maintained active during idle periods in between data reception.
Power Management
The KSZ8993M features a per-port power down mode. To save power, the user can power down ports that are
not in use by setting the port control registers, or MII control registers. In addition, there is a full chip power down
mode. When activated, the entire chip will be shut down.
MDI /MDI-X Auto Crossover
The KSZ8993M supports MDI/ DI-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 KSZ8993M device. This feature can be extremely useful
when end users are unaware of cable types and can also save on an additional uplink configuration connection.
The auto-crossover feature can be disabled through the port control registers.
Based on the IEEE 802.3 standard, the MDI and MDI-X definitions are as follows:
Micrel, Inc.
October 2008
RJ45 Pins
1
2
3
6
MDI
Table 2. MDI/MDI-X Pin Definitions
Signals
TD+
RD+
TD-
RD-
23
RJ-45 Pins
1
2
3
6
MDI-X
Signals
RD+
TD+
RD-
TD-
M9999-020606
KSZ8993M/ML