KSZ8091MLX Datasheet, PDF (18/70 Pages) Micrel Semiconductor – 10Base-T/100Base-TX Physical Layer Transceiver

KSZ8091MLX
3.3 Back-to-Back Mode – 100 Mbps Copper Repeater
Two KSZ8091MLX devices can be connected back-to-back to form a 100BASE-TX copper repeater.
FIGURE 3-3:
KSZ8091MLX TO KSZ8091MLX BACK-TO-BACK COPPER REPEATER
RXP/RXM
RxD
TXP/TXM
KSZ8091MLX
TxD
(COPPER MODE)
XI
XI
TXP/TXM
RXP/RXM
KSZ8091MLX
TxD
(COPPER MODE)
RxD
25MHz
OSC
3.3.1 MII BACK-TO-BACK MODE
In MII back-to-back mode, a KSZ8091MLX interfaces with another KSZ8091MLX to provide a complete 100 Mbps cop-
per repeater solution.
The KSZ8091MLX devices are configured to MII back-to-back mode after power-up or reset with the following:
• Strap-in pin CONFIG[2:0] (pins 27, 41, 40) set to 110.
• A common 25 MHz reference clock connected to XI (Pin 15) of both KSZ8091MLX devices.
• MII signals connected as shown in Table 3-2.
TABLE 3-2: MII SIGNAL CONNECTION FOR MII BACK-TO-BACK MODE (100BASE-TX COPPER
REPEATER)
KSZ8091MLX (100BASE-TX Copper)
[Device 1]
KSZ8091MLX (100BASE-TX Copper)
[Device 2]
Pin Name
RXDV
RXD3
RXD2
RXD1
RXD0
TXEN
TXD3
TXD2
TXD1
TXD0
Pin Number
27
20
21
22
23
34
39
38
36
35
Pin Type
Output
Output
Output
Output
Output
Input
Input
Input
Input
Input
Pin Name
TXEN
TXD3
TXD2
TXD1
TXD0
RXDV
RXD3
RXD2
RXD1
RXD0
Pin Number
34
39
38
36
35
27
20
21
22
23
Pin Type
Input
Input
Input
Input
Input
Output
Output
Output
Output
Output
DS00002297A-page 18
 2016 Microchip Technology Inc.