DM9000
ISA to Ethernet MAC Controller with Integrated 10/100 PHY
36
Final
Version: DM9000-DS-F02
June 26, 2002
9.11 Power Reduced Mode
The Signal detect circuit is always turned to monitor whether
there is any signal on the media (cable disconnected). The
DM9000 automatically turns off the power and enters the
Power Reduced mode, whether its operation mode is N-
way or force mode. When enters the Power Reduced
mode, the transmit circuit still sends out fast link pules with
minimum power consumption. If a valid signal is detected
from the media, which might be N-ways fast link pules,
10Base-T normal link pules, or 100Base-TX MLT3 signals,
the device will wak e up and resum e a normal
operation mode.
That can be writing Zero to Reg.16.4 of MII register to
disable Power Reduced mode.
9.11.1 Power Down Mode
The Reg.0.11 of MII register can be set high to enter the
Power Down mode, which disables all transmit, receive
functions and MII interface functions, except the MDC/MDIO
management interface.
9.11.2 Reduced Transmit Power Mode
The additional Transmit power reduction can be
gained by designing with 1.25:1 turns ration magnetic
on its TX side and using a 8.5K
Ω
resistor on BGRES
and AGND pins, and the TXO+/TXO- pulled high
resistors should be changed from 50
Ω
to 78
Ω
.
This configuration could be reduced about 20%
transmit power.