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

Datasheet

Chapter 3 Pin Description

This chapter describes the signals on each pin. When a lower case “n” is used at the beginning of the signal name, it indicates that the signal is active low. For example, nRST indicates that the reset signal is active low. The buffer type for each signal is indicated in the TYPE column, and a description of the buffer types is provided in Table 3.1.

 

Table 3.1 Buffer Types

 

 

BUFFER TYPEDESCRIPTION

 

 

I8

Input.

 

 

O8

Output with 8mA sink and 8mA source.

 

 

IOD8

Input/Open-drain output with 8mA sink.

 

 

IPU

Input with 67k (typical) internal pull-up.

Note 3.1

 

 

 

IPD

Input with 67k (typical) internal pull-down.

Note 3.1

 

 

 

IOPU

Input/Output with 67k (typical) internal pull-up. Output has 8mA sink and 8mA source.

Note 3.1

 

 

 

IOPD

Input/Output with 67k (typical) internal pull-down. Output has 8mA sink and 8mA source.

Note 3.1

 

 

 

AI

Analog input

 

 

AIO

Analog bi-directional

 

 

ICLK

Crystal oscillator input pin

 

 

OCLK

Crystal oscillator output pin

 

 

P

Power pin

 

 

Note 3.1 Unless otherwise noted in the pin description, internal pull-up and pull-down resistors are always enabled. The internal pull-up and pull-down resistors prevent unconnected inputs from floating, and must not be relied upon to drive signals external to LAN8720/LAN8720i. When connected to a load that must be pulled high or low, an external resistor must be added.

Note: The digital signals are not 5V tolerant.They are variable voltage from +1.6V to +3.6V, as shown in Table 7.1.

Revision 1.0 (05-28-09)

14

SMSC LAN8720/LAN8720i

 

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