SMSC LAN91C111 - Manual (Page 32)

10/100 Non-PCI Ethernet Single Chip MAC + PHY
Datasheet
Revision 1.91 (08-18-08) 32 SMSC LAN91C111 REV C
DATASHEET
Transmit Level Adjust
The transmit output current level is derived from an internal reference voltage and the external resistor
on RBIAS pin. The transmit level can be adjusted with either (1) the external resistor on the RBIAS
pin, or (2) the four transmit level adjust bits in the PHY Ml serial port Configuration 1 register as shown
in
Table 7.2 . The adjustment range is approximately -14% to +16% in 2% steps.
Transmit Rise and Fall Time Adjust
The transmit output rise and fall time can be adjusted with the two transmit rise/fall time adjust bits in
the PHY Ml serial port Configuration 1. The adjustment range is -0.25ns to +0.5ns in 0.25ns steps.
Q 111 0.15
R 111 0
S 111 -0.15
T 110 -1.0
U 100 -0.3
V 110 -0.7
W 90 -0.7
Table 7.2 Transmit Level Adjust
TLVL[3:0] GAIN
0000 1.16
0001 1.14
0010 1.12
0011 1.10
0100 1.08
0101 1.06
0110 1.04
0111 1.02
1000 1.00
1001 0.98
1010 0.96
1011 0.94
1100 0.92
1101 0.90
1110 0.88
1111 0.86
REFERENCE TIME (NS) INTERNAL MAU VOLTAGE (V)