KSZ8893FQL-FX Micrel Inc, KSZ8893FQL-FX Datasheet - Page 29

• Manufacturer Part Number: KSZ8893FQL-FX
• Description: 2+1 Port 10/100 Switch W/Tranceivers & Frame Buffers, ( )
• Manufacturer: Micrel Inc

Specifications of KSZ8893FQL-FX

• Controller Type: Ethernet Switch Controller
• Interface: MII, RMII, SNI
• Voltage - Supply: 3.1 V ~ 3.5 V
• Operating Temperature: -40°C ~ 85°C
• 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): 3.3V
• Fiber Support: Yes
• Integrated Led Drivers: Yes
• Power Supply Type: Analog/Digital
• Package Type: PQFP
• Vlan Support: Yes
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Pin Count: 128
• Mounting: Surface Mount
• Jtag Support: No
• Operating Temperature Classification: Commercial
• Data Rate: 1000Mbps
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 576-1603 - EVAL KIT EXPERIMENTAL KSZ8893MQL
• Current - Supply: -
• Lead Free Status / RoHS Status: Compliant, Lead free / RoHS Compliant
• Other names: 576-3273

Micrel, Inc.
100Base-FX Operation
100Base-FX operation is similar to 100Base-TX operation with the differences being that the scrambler/de-scrambler
and MLT3 encoder/decoder are bypassed on transmission and reception. In addition, auto-negotiation is bypassed and
auto MDI/MDI-X is disabled.
100Base-FX Signal Detection
In 100Base-FX operation, FXSD1 (fiber signal detect), input pin 44, is usually connected to the fiber transceiver SD
(signal detect) output pin. 100Base-FX mode is activated when the FXSD1 input pin is greater than 1V. When FXSD1 is
between 1V and 1.8V, no fiber signal is detected and a far-end fault (FEF) is generated. When FXSD1 is over 2.2V, the
fiber signal is detected.
Alternatively, the designer may choose not to implement the FEF feature. In this case, the FXSD1 input pin is tied high
to force 100Base-FX mode.
100Base-FX signal detection is summarized in the following table:
To ensure proper operation, a resistive voltage divider is recommended to adjust the fiber transceiver SD output voltage
swing to match the FXSD1 pin’s input voltage threshold.
100Base-FX Far-End Fault
A far-end fault (FEF) occurs when the signal detection is logically false on the receive side of the fiber transceiver. The
KSZ8893FQL detects a FEF when its FXSD1 input is between 1V and 1.8V. When a FEF is detected, the
KSZ8893FQL signals its fiber link partner that a FEF has occurred by sending 84 1’s followed by a zero in the idle
period between frames.
By default, FEF is enabled. FEF can be disabled through register setting.
10Base-T Transmit
The 10Base-T driver is incorporated with the 100Base-TX driver to allow for transmission using the same magnetics.
They are internally wave-shaped and pre-emphasized into outputs with typical 2.3V amplitude. The harmonic contents
are at least 27dB below the fundamental frequency 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 phase-locked loop (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 to
prevent noise 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 KSZ8893FQL decodes a data frame. The receiver clock is maintained
active during idle periods in between data reception.
Fiber LED Driver
The device provides a current mode fiber LED driver. The edge enhanced current mode does not require any output
wave shaping. The drive current of the fiber LED driver is programmable thru register 138 (0x8A) bit[7:6]. The
programmable current values are as follow:
October 2007
FXSD1 Input Voltage
Less than 0.2V
Greater than 1V, but less than 1.8V
Greater than 2.2V
Table 5. FX and TX Mode Selection
Mode
TX mode
FX mode
No signal detected
Far-end fault generated
FX mode
Signal detected
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M9999-101607-1.3
KSZ8893FQL