KSZ8895 INFINEON [Infineon Technologies AG], KSZ8895 Datasheet - Page 30

• Manufacturer Part Number: KSZ8895
• Description: Integrated 5-Port 10/100 Managed Ethernet Switch with MII/RMII interface
• Manufacturer: INFINEON [Infineon Technologies AG]

Micrel, Inc.
On-chip Termination Resistors
The KSZ8895MQ/RQ/FMQ reduces the board cost and simplifies the board layout by using on-chip termination
resistors for all ports and RX/TX differential pairs without the external termination resistors. The solution of the on
chip termination and internal biasing will save about 500 to 1000mw power consumption in system level compare
with regular using external biasing and termination resistors, and the transformer will not consume power any more.
And the center tap of the transformer doesn’t need to be tied to the analog power and do not tie the center taps
together between RX and TX pairs for its application.
Internal 1.2V LDO Controller
The KSZ8895MQ/RQ/FMQ reduces board cost and simplifies board layout by integrating an internal 1.2V LDO
controller to drive a low cost MOSFET to supply the 1.2V core power voltage for a single 3.3V power supply solution.
The internal 1.2V LDO controller can be disabled by the pin 126 IN_PWR_SEL pull-down if want to use an external
1.2V LDO.
Functional Overview: Power Management
The KSZ8895MQ/RQ/FMQ supports a full chip hardware power down mode. When activated low, internally the
PWRDN pin 47 (pin PWRDN =0), the entire chip is powered down. If this pin is de-asserted, the chip will be internal
reset.
The KSZ8895MQ/RQ/FMQ can also use multiple power level of 3.3V, 2.5V or 1.8V for VDDIO to support different I/O
voltage.
The KSZ8895MQ/RQ/FMQ supports enhanced power management feature in low power state with energy detection
to ensure low-power dissipation during device idle periods. There are five operation modes under the power
management function which is controlled by the Register 14 bit [4:3] and the Port Register Control 13 bit3 as shown
below:
Register 14 bit [4:3] = 00 Normal Operation Mode
Register 14 bit [4:3] = 01 Energy Detect Mode
Register 14 bit [4:3] = 10 Soft Power Down Mode
Register 14 bit [4:3] = 11 Power Saving Mode
The Port Register 29, 45, 61, 77, 93 Control 13 bit 3 =1 are for the Port Based Power-Down Mode.
Table 2 indicates all internal function blocks status under four different power management operation modes.
Normal Operation Mode
This is the default setting bit [4:3] =00 in register 14 after the chip power-up or hardware reset. When
KSZ8895MQ/RQ/FMQ is in this normal operation mode, all PLL clocks are running, PHY and MAC are on and the
host interface is ready for CPU read or write.
During the normal operation mode, the host CPU can set the bit [4:3] in register 14 to transit the current normal
operation mode to any one of the other three power management operation modes.
January 2011
KSZ8895MQ/RQ/FMQ
Internal PLL Clock
Function Blocks
Host Interface
Tx/Rx PHY
MAC
Normal Mode
Enabled
Enabled
Enabled
Enabled
Table 2. Internal Function Block Status
Rx unused block disabled
Power Saving Mode
Enabled
Enabled
Enabled
Power Management Operation Modes
30
Energy Detect Mode
Energy detect at Rx
Disabled
Disabled
Disabled
Soft Power Down Mode
KSZ8895MQ/RQ/FMQ
Disabled
Disabled
Disabled
Disabled
M9999-012011-1.2