DS100KR401_13 Datasheet, PDF (9/38 Pages) Texas Instruments – Ultra Low Power, 4 Lane (8-channel, bi-directional) Repeater for Data-rates up to 10.3 Gbps

DS100KR401
www.ti.com
SNLS395B – JANUARY 2012 – REVISED MARCH 2012
FUNCTIONAL DESCRIPTIONS
The DS100KR401 is a low power media compensation 4 lane repeater optimized for 10G–KR. The DS100KR401
compensates for lossy FR-4 printed circuit board backplanes and balanced cables. The DS100KR401 operates
in 3 modes: Pin Control Mode (ENSMB = 0), SMBus Slave Mode (ENSMB = 1) and SMBus Master Mode
(ENSMB = float) to load register informations from external EEPROM; please refer to SMBUS Master Mode for
additional information.
Pin Control Mode:
When in pin mode (ENSMB = 0) , the repeater is configurable with external pins. Equalization and de-emphasis
can be selected via pin for each side independently. When de-emphasis is asserted VOD is automatically
adjusted per the De-Emphasis table below. The receiver electrical idle detect threshold is also adjustable via the
SD_TH pin.
SMBUS Mode:
When in SMBus mode (ENSMB = 1), the VOD (output amplitude), equalization, de-emphasis, and termination
disable features are all programmable on a individual lane basis, instead of grouped by A or B as in the pin mode
case. Upon assertion of ENSMB the MODE, EQx and DEMx functions revert to register control immediately. The
EQx and DEMx pins are converted to AD0-AD3 SMBus address inputs. The other external control pins remain
active unless their respective registers are written to and the appropriate override bit is set, in which case they
are ignored until ENSMB is driven low (pin mode). On power-up and when ENSMB is driven low all registers are
reset to their default state. If RESET is asserted while ENSMB is high, the registers retain their current state.
Equalization settings accessible via the pin controls were chosen to meet the needs of most applications. If
additional fine tuning or adjustment is needed, additional equalization settings can be accessed via the SMBus
registers. Each input has a total of 256 possible equalization settings. The tables show the 16 setting when the
device is in pin mode. When using SMBus mode, the equalization, VOD and de-Emphasis levels are set by
registers.
The input control pins have been enhanced to have 4 different levels and provide a wider range of control
settings when ENSMB=0.
Table 1. 4–Level Control Pin Settings⁽¹⁾
Pin Setting
0
R
Float
1
Description
Tie 1kΩ to GND
Tie 20kΩ to GND
Float (leave pin open)
Tie 1kΩ to VDD
Voltage at Pin
0.03 x VDD
1/3 x VDD
2/3 x VDD
0.98 x VDD
(1) The above required resistor value is for a single device. When there are multiple devices connected to the pull-up / pull-down resistor,
the value must scale with the number of devices. If 4 devices are connected to a single pull-up or pull-down, the 1kΩ resistor value
should be 250Ω. For the 20kΩ to GND, this should also scale to 5kΩ.
3.3V or 2.5V Supply Mode Operation
The DS100KR401 has an optional internal voltage regulator to provide the 2.5V supply to the device. In 3.3V
mode, the VIN pin = 3.3V is used to supply power to the device and the VDD pins should be left open. The
internal regulator will provide the 2.5V to the VDD pins of the device and a 0.1 µF cap is needed at each of 5
VDD pins for power supply de-coupling (total capacitance should be ≤0.5 µF). The VDD_SEL pin must be tied to
GND to enable the internal regulator. In 2.5V mode, the VIN pin should be left open and 2.5V supply must be
applied to the VDD pins. The VDD_SEL pin must be left open (no connect) to disable the internal regulator.
Copyright © 2012, Texas Instruments Incorporated
Product Folder Links: DS100KR401
Submit Documentation Feedback
9