Texas Instruments DS125DF111EVM User manual

DS125DF111EVM Evaluation Board
User's Guide
Literature Number: SNLU158A
January 2014–Revised January 2016

2SNLU158A–January 2014–Revised January 2016
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Table of Contents
Contents
1 Overview............................................................................................................................. 4
2 Features.............................................................................................................................. 5
3 Applications ........................................................................................................................ 5
4 Ordering Information............................................................................................................ 5
5 Setup.................................................................................................................................. 6
5.1 Pin Control Mode......................................................................................................... 6
5.2 SMBus Slave Mode...................................................................................................... 9
5.3 EEPROM Mode......................................................................................................... 12
6 EVM Layout ....................................................................................................................... 13
7 Schematic ......................................................................................................................... 14
8 Bill of Materials .................................................................................................................. 15
9 Example Waveforms........................................................................................................... 16
Revision History.......................................................................................................................... 18

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List of Figures
List of Figures
1 DS125DF111EVM........................................................................................................... 4
2 4-Level I/O Control on DS125DF111EVM................................................................................ 6
3 DS1xxDF111EVM Slave Mode Full Setup ............................................................................... 9
4 DS1xxDF111EVM Slave Mode Close-Up ................................................................................ 9
5 DS125DF111 High Level Page........................................................................................... 10
6 DS125DF111 Low Level Page ........................................................................................... 11
7 DS125DF111 Eye Monitor Page......................................................................................... 11
8 DS125DF111 EEPROM Hex File Generation Page................................................................... 12
9 Top Assembly Layer....................................................................................................... 13
10 Bottom Assembly Layer ................................................................................................... 13
11 10.3125 Gbps Output Waveform......................................................................................... 16
12 10.3125 Gbps Rj/Dj Jitter Decomposition............................................................................... 17
List of Tables
1 Four-Level Logic Settings................................................................................................... 6
2 DS125DF111 VOD Levels.................................................................................................. 7
3 DS125DF111 DEM Levels.................................................................................................. 7
4 DS125DF111 Loopback Control........................................................................................... 8
5 SMBus Write Address Assignment ...................................................................................... 10

4SNLU158A–January 2014–Revised January 2016
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DS125DF111EVM Evaluation Board
User's Guide
SNLU158A–January 2014–Revised January 2016
DS125DF111EVM Evaluation Board
1 Overview
The Texas Instruments DS125DF111EVM evaluation module provides a high bandwidth platform with an
SMA interface to evaluate the DS125DF111 dual channel retimer with integrated signal conditioning. The
DS125DF111 includes an input Continuous-Time Linear Equalizer (CTLE), Clock and Data Recovery
(CDR), and transmit driver on each channel.
Figure 1. DS125DF111EVM

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DS125DF111EVM Evaluation Board
2 Features
• Adjustable Transmit VOD: 600 to 1300 mVp-p
• Settable Transmit De-emphasis Driver to -12 dB
• Low Power Consumption: 200 mW/Channel
• Locks to Half/Quarter/Eighth Data Rates for Legacy Support
• On-chip Eye Monitor (EOM), PRBS Generator
3 Applications
• Front Port Optical Interconnects
• SFF-8431
• 10G/1G Ethernet
• CPRI
4 Ordering Information
EVM ID DEVICE ID DEVICE PACKAGE
DS125DF111EVM DS125DF111SQ 24WQFN

HIGH
SIGNAL
RESISTOR
SIGNAL
LOW
4-LEVEL CONTROL
HIGH RESISTOR FLOAT LOW
PIN HEADER CONNECTION
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5 Setup
This section describes the jumpers and connectors on the EVM as well as how to properly connect, set
up, and use the DS125DF111EVM.
The DS125DF111EVM can be used in three different modes:
1. Pin Control Mode – provides access to selected signal integrity settings.
2. SMBus Slave Mode – provides full access to signal integrity and control settings.
3. EEPROM Mode – provides full access to signal integrity and control settings. EEPROM mode is a
convenient method of programming one or more DS125DF111 devices on system power up when an
SMBus master (microcontroller or similar) is unavailable in the design.
This EVM and documentation focus on Pin Control and SMBus Slave Mode to highlight the ease-of-use
and excellent low-jitter performance of the DS125DF111.
5.1 Pin Control Mode
In Pin Control Mode, the external control pins on the DS125DF111 are used to configure the signal
integrity and control settings of the device. In this mode, only a subset of the VOD and de-emphasis
(DEMA/B) levels are available. Due to the limited number of control pins, a limited bandwidth 4-level input
scheme has been implemented across the control pin interface. This allows for improved DE and VOD
control with fewer physical pins.
The four levels are defined below:
Table 1. Four-Level Logic Settings
Level Input Pin Setting
Low - 0 1 kΩto GND
Resistor - R 20 kΩto GND
Float - F Open
High - 1 1 kΩto VDD
The EVM interfaces to this 4-level I/O using the setup in Figure 2. Only one shunt connection is required
to access any of the four levels. This methodology minimizes the risk of improper connections that could
damage the board or board power supply.
Figure 2. 4-Level I/O Control on DS125DF111EVM

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5.1.1 Pin Control Mode Configuration
The DS125DF111EVM is shipped ready-to-use in pin control mode. The EVM requires the following power
supply inputs and jumper settings:
1. J17 – GND
2. J19 – VIN to VIH: 3.3 V supply operation (2.5 V internal regulator is enabled)
3. J15 – VIN = 3.3 V: Use internal regulator to convert 3.3V supply to internal supply level of 2.5 V
NOTE: The 2.5 V level may be observed on J18 (VDD) or the device VDD pins. While in 3.3 V mode,
J18 (VDD) is a regulated output voltage. Do not connect a 2.5 V supply to this pin.
4. J3 – ENSMB = 1 kΩto GND (L): Pin Control Mode
5. J6 – LBK = 1 kΩto VIN (H): Normal operation, INA - to - OUTA and INB - to - OUTB
6. J91 – VODA = 1 kΩto GND (L): 600 mV output VOD on OUTA
7. J10 – VODB = 1 kΩto GND (L): 600 mV output VOD on OUTB
8. J41 – DEMA = 1 kΩto GND (L): 0 dB de-emphasis on OUTA
9. J51 – DEMB = 1 kΩto GND (L): 0 dB de-emphasis on OUTB
10. J161 – LOCK: With shunt installed, LOCK LED will light Green when DS125DF111 CDR is in the
locked state
5.1.2 VOD and De-Emphasis
The DS125DF111EVM uses pin strapping to define the VOD and DE level of the outputs. These are set
by the following jumpers on the DS125DF111EVM:
• VODA – J9 / J91
• VODB – J10
• DEMA – J4 / J41
• DEMB – J5 / J51
See Table 2 and Table 3 for a complete list of VOD and DE settings.
Table 2. DS125DF111 VOD Levels
VODA/B Bit 2,
sel_vod[2] Bit 1, sel_vod[1] Bit 0, sel_vod[0] Output VOD (mVppd)
0 0 0 0 600
R0 0 1 700 0 1 0 800
0 1 1 900
F 1 0 0 1000
11 0 1 1100 1 1 0 1200
1 1 1 1300
Table 3. DS125DF111 DEM Levels
DEMA/B Reg 0x15
Bit [2] Reg 0x15 Bit [1] Reg 0x15 Bit [0] Reg 0x15 Bit [6] De-Emphasis (dB)
00 0 0 0 0.0
0 0 1 1 -0.9
R
0 0 1 0 -1.5
0 1 0 1 -2.0
0 1 1 1 -2.8
1 0 0 1 -3.3

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Table 3. DS125DF111 DEM Levels (continued)
DEMA/B Reg 0x15
Bit [2] Reg 0x15 Bit [1] Reg 0x15 Bit [0] Reg 0x15 Bit [6] De-Emphasis (dB)
F
0 1 0 0 -3.5
1 0 1 1 -3.9
1 1 0 1 -4.5
0 1 1 0 -5.0
1 1 1 1 -5.6
1
1 0 0 0 -6.0
1 0 1 0 -7.5
1 1 0 0 -9.0
1 1 1 0 -12.0
5.1.3 Equalization
There are no pin control settings for the input equalization. The DS125DF111 input equalization will
automatically adapt for divide ratios 1 and 2. For divide ratios 4 and 8, a pre-set equalization level is used.
5.1.4 Loopback
J6 and J61 control the DS125DF111EVM loopback function according to Table 4.
Table 4. DS125DF111 Loopback Control
Loopback Mode of Operation IN A IN B
0 Loopback Output B Output A
R Fanout Input A Output A Output A
F Fanout Input B Output B Output B
1 Normal Operation Output A Output B
5.1.5 LOS and LOCK
• LOS Function: The LOS function monitors the input of channel A for a valid signal. When there is a
valid signal on input A the LED will light up. Channel B does not have any effect on the LOS output
signal.
• LOCK Function: The LOCK function monitors both channel A and channel B for a valid lock condition.
If either channel has a valid lock the LED will light up.

DPS-DONGLE-EVM
SMBus Pin Headers
SCL | SDA | GND
DS1xxDF111EVM
SMBus Pin Headers
SCL
SDA
GND
DPS-DONGLE-EVM
DS1xxDF111EVM
PC running either DS110DF111 or
DS125DF111 profile in SigCon Architect
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5.2 SMBus Slave Mode
The SMBus can also be used to control DS125DF111 devices. This method has the advantage of
independent channel control and finer signal conditioning granularity.
1. J17 – GND
2. J19 – VIN to VIH: 3.3 V supply operation (2.5 V internal regulator is enabled)
3. J15 – VIN = 3.3 V: Use internal regulator to convert 3.3 V supply to internal supply level of 2.5 V
NOTE: The 2.5V level may be observed on J18 (VDD) or the device VDD pins. While in 3.3 V mode,
J18 (VDD) is a regulated output voltage. Do not connect a 2.5 V supply to this pin.
4. Floating the AD[1:0] inputs will result in an SMBus address = 00 = 30’h
5. J3 – ENSMB = H: SMBus Slave Mode
6. Connect the board signals SDA, SCL, and GND on J20 to a DPS-DONGLE-EVM or an equivalent
USB2ANY device. A pull-up resistor is needed on the SMBus clock and data signals; place jumpers on
pins 1-2 of J4 and J5 to connect a 1 kΩpull-up resistor to SCL and SDA. The address line settings on
J16 (ADR0) and J10 (ADR1) are pin strap settings which get latched on power up and retain their
value until the DS125DF111 is power cycled.
7. The DS125DF111's control and signal integrity settings are programmable with SigCon Architect, a
GUI which supports full register access through SMBus communication. An example of a
DS1xxDF111EVM connected to a PC through a DPS-DONGLE-EVM is shown in Figure 3 and
Figure 4. The possible SMBus address settings are shown in Table 5. For more information about
SigCon Architect, reference the "SigCon Architect: Installation and Starter's Guide" (SNLU178).
Figure 3. DS1xxDF111EVM Slave Mode Full Setup Figure 4. DS1xxDF111EVM Slave Mode Close-Up

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(1) A floating ADDR[1:0] pin at power-up will be interpreted as a logic 0.
Table 5. SMBus Write Address Assignment(1)
ADDR1 ADDR0 SMBus Write SMBus Read
0 0 0x30 0x31
0 1 0x32 0x33
1 0 0x34 0x35
1 1 0x36 0x37
5.2.1 Register Architecture and Bit Fields
There are two types of device registers in the DS125DF111. These are the Control/Share Registers and
the Channel Registers. The Control/Share Registers control or allow observation of settings which affect
the operation of all channels of the DS125DF111. They are also used to select which channel of the
device is to be the target channel for reads from and writes to the Channel Registers.
The Channel Registers are used to set all the configuration settings of the DS125DF111. They provide
independent control for each channel of the DS125DF111 for all the configurable device characteristics.
Any registers not described in the datasheet tables should be treated as Reserved. The user should not
try to write new values to these registers. The user-accessible registers described in the datasheet provide
a complete capability for customizing the operation of the DS125DF111 on a channel-by-channel basis.
Many of the registers in the DS125DF111 are divided into bit fields. This allows a single register to serve
multiple purposes, which may be unrelated. Often configuring the DS125DF111 requires writing a bit field
that makes up only part of a register value while leaving the remainder of the register value unchanged.
5.2.2 Using SigCon Architect
SigCon Architect can be used to program the DS125DF111EVM. In order to use SigCon Architect for
SMBus Slave Mode access control, a DPS-DONGLE-EVM (see SNLU184) or USB2ANY equivalent
adapter board must be used. This adapter board serves as an interface board to allow SMBus
communication between the PC and the DS125DF111 retimer. The SigCon Architect GUI features high
level control, low level register bit level control, and an Eye Monitor page to program the device. Examples
of these pages are shown in the following figures.
Figure 5. DS125DF111 High Level Page