KSZ8041TL A3 Micrel Inc, KSZ8041TL A3 Datasheet - Page 39

• Manufacturer Part Number: KSZ8041TL A3
• Manufacturer: Micrel Inc

Specifications of KSZ8041TL A3

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Micrel, Inc.
RMII Back-to-Back Mode (KSZ8041TL/FTL only)
In RMII Back-to-Back mode, the KSZ8041TL interfaces with another KSZ8041TL, or a KSZ8041FTL to provide a complete
100Mbps repeater or media converter solution. The KSZ8041TL/FTL devices are configured to RMII Back-to-Back mode
after they are power-up or reset with the following:
RMII Back-to-Back mode provides an option to disable the fiber side when the copper side is down. This, effectively,
produces a link fault propagation for media converter applications, such that a copper side link down will automatically
disable the fiber side. This KSZ8041TL/FTL feature functions as follows:
The TXD3 and TXD2 pins should be pulled down with 1K resistors, and RXD3 and RXD2 pins should be left floating, if
they are not used.
December 2009
x
x
x
x
x
CONFIGURATION[2:0] (pins 27, 41, 40) set to ‘101’
A common 50MHz reference clock connected to REFCLK (pin 15)
RMII signals connected as shown in the following table.
On the KSZ8041TL copper side, RXD2 (pin 21) indicates if there is energy detected at the receive inputs of the
copper port. RXD2 outputs a low if there is no energy detected (cable disconnected), and outputs a high if there is
energy detected (cable connected).
The RXD2 output of the KSZ8041TL copper side drives the input of an inverter, and the output of the inverter
drives the TXD2 (pin 38) input of the KSZ8041FTL fiber side. The fiber side transmitter is disabled if the TXD2
input is high.
Pin Name
CRSDV
RXD1
RXD0
TXEN
TXD1
TXD0
KSZ8041TL (100Base-TX copper)
Pin Number
Table 13. RMII Signal Connection for RMII Back-to-Back Mode
27
22
23
34
36
35
Pin Type
Output
Output
Output
Input
Input
Input
39
Pin Name
CRSDV
TXEN
TXD1
TXD0
RXD1
RXD0
KSZ8041TL (100Base-TX copper)
KSZ8041FTL (100Base-FX fiber)
Pin Number
34
36
35
27
22
23
Pin Type
Output
Output
Output
KSZ8041TL/FTL/MLL
Input
Input
Input
M9999-120909-1.2