SMSC LAN8720i User Manual

Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support

SMSC LAN8720/LAN8720i

33

Revision 1.0 (05-28-09)

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 

.

 

 

~270 ohms

nINTSEL = 0

LED output = active high

10K 

~270 ohms

 

 

nINTSEL = 1

LED output = active low

 

 

~270 ohms

REGOFF = 0

LED output = active high

~270 ohms

 

 

REGOFF  = 1 (Regulator OFF)

LED output = active low

10K