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

4.11REGOFF 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)

REGOFF = 0

LED output = active low

LED output = active high

VDD2A

 

 

LED1/REGOFF

 

 

 

 

 

 

 

 

 

 

10K

~270 ohms

~270 ohms

LED1/REGOFF

Figure 4.9 REGOFF Configuration on LED1

SMSC LAN8720/LAN8720i

33

Revision 1.0 (05-28-09)

 

DATASHEET