Setup
7
SNLU158A – January 2014 – Revised January 2016
Copyright © 2014–2016, Texas Instruments Incorporated
DS125DF111EVM Evaluation Board
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 – V
IN
to V
IH
: 3.3 V supply operation (2.5 V internal regulator is enabled)
3. J15 – V
IN
= 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 (V
DD
) or the device V
DD
pins. While in 3.3 V mode,
J18 (V
DD
) is a regulated output voltage. Do not connect a 2.5 V supply to this pin.
4. J3 – ENSMB = 1 k
Ω
to GND (L): Pin Control Mode
5. J6 – LBK = 1 k
Ω
to V
IN
(H): Normal operation, INA - to - OUTA and INB - to - OUTB
6. J91 – VODA = 1 k
Ω
to GND (L): 600 mV output VOD on OUTA
7. J10 – VODB = 1 k
Ω
to GND (L): 600 mV output VOD on OUTB
8. J41 – DEMA = 1 k
Ω
to GND (L): 0 dB de-emphasis on OUTA
9. J51 – DEMB = 1 k
Ω
to 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
and
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
R
0
0
1
700
0
1
0
800
0
1
1
900
F
1
0
0
1000
1
1
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)
0
0
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
