Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
Datasheet
nINTSEL = 1
nINTSEL = 0
LED output = active low
LED output = active high
VDD2A
LED2/nINTSEL
10K
~270 ohms
~270 ohms
LED2/nINTSEL
Figure 4.8 nINTSEL Strapping on LED2
4.11
REGOFF and LED Polarity Selection
The REGOFF configuration pin is shared with the LED1 pin. The LED1 output will automatically
change polarity based on the presence of an external pull-up resistor. If the LED pin is pulled high to
VDD2A by an external pull-up resistor to select a logical high for REGOFF, then the LED output will
be active low. If the LED pin is pulled low by the internal pull-down resistor to select a logical low for
REGOFF, the LED output will then be an active high output.
To set REGOFF without LEDs, pull-up the pin with an external resistor to VDDIO to disable the
regulator. See Figure 4.9.
REGOFF = 1 (Regulator OFF)
LED output = active low
REGOFF = 0
LED output = active high
VDD2A
LED1/REGOFF
10K
~270 ohms
~270 ohms
LED1/REGOFF
Figure 4.9 REGOFF Configuration on LED1
SMSC LAN8720/LAN8720i
Revision 1.0 (05-28-09)
DATA3S3HEET
SMSC [ SMSC CORPORATION ]
