®
Small Footprint MII/RMII 10/100 Ethernet Transceiver with HP Auto-MDIX and flexPWR Technology
Datasheet
pin is pulled low by an external pull-down resistor to select a logical low for nINTSEL, the LED2 output
will then be an active high output. Figure 3.8 details the LED2 polarity for each nINTSEL configuration.
nINTSEL = 1
nINTSEL = 0
LED output = Active Low
LED output = Active High
VDD2A
LED2/nINTSEL
10K
~270 ohms
~270 ohms
LED2/nINTSEL
Figure 3.8 LED2/nINTSEL Polarity Configuration
Note: Refer to Section 3.7.5, "nINTSEL: nINT/TXER/TXD4 Configuration," on page 38 for additional
information on the nINTSEL configuration strap.
3.8.2
Variable Voltage I/O
The device’s digital I/O pins are variable voltage, allowing them to take advantage of low power savings
from shrinking technologies. These pins can operate from a low I/O voltage of +1.62V up to +3.6V.
The applied I/O voltage must maintain its value with a tolerance of ± 10%. Varying the voltage up or
down after the transceiver has completed power-on reset can cause errors in the transceiver operation.
Refer to Chapter 5, "Operational Characteristics," on page 66 for additional information.
Note: Input signals must not be driven high before power is applied to the device.
3.8.3
Power-Down Modes
There are two device power-down modes: General Power-Down Mode and Energy Detect Power-
Down Mode. These modes are described in the following subsections.
3.8.3.1
General Power-Down
This power-down mode is controlled via the Power Down bit of the Basic Control Register. In this
mode, the entire transceiver (except the management interface) is powered-down and remains in this
mode as long as the Power Down bit is “1”. When the Power Down bit is cleared, the transceiver
powers up and is automatically reset.
3.8.3.2
Energy Detect Power-Down
This power-down mode is activated by setting the EDPWRDOWN bit of the Mode Control/Status
Register. In this mode, when no energy is present on the line the transceiver is powered down (except
for the management interface, the SQUELCH circuit, and the ENERGYON logic). The ENERGYON
logic is used to detect the presence of valid energy from 100BASE-TX, 10BASE-T, or Auto-negotiation
signals.
In this mode, when the ENERGYON bit of the Mode Control/Status Register is low, the transceiver is
powered-down and nothing is transmitted. When energy is received via link pulses or packets, the
ENERGYON bit goes high and the transceiver powers-up. The device automatically resets into the
Revision 1.4 (08-23-12)
40
SMSC LAN8710A/LAN8710Ai
DATASHEET
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