DS125BR820 Datasheet, PDF (16/62 Pages) Texas Instruments – Low-Power 12.5 Gbps 8-Channel Linear Repeater

DS125BR820
SNLS491B – JULY 2014 – REVISED FEBRUARY 2015
www.ti.com
Signal Conditioning Settings (continued)
Table 4. Equalizer Settings⁽¹⁾⁽²⁾
LEVEL
1
2
3
4
EQA ⁽³⁾
EQB
0
R
F
1
EQUALIZATION BOOST RELATIVE to DC
EQ – 8 bits[7:0]
dB at
1.5 GHz
dB at
2.5 GHz
xxxx xx00 = 0x00
2.1
2.5
xxxx xx01 = 0x01
4.0
5.1
xxxx xx10 = 0x02
5.5
7.0
xxxx xx11 = 0x03
6.8
8.3
dB at
4 GHz
2.7
6.4
8.3
9.5
dB at
5 GHz
2.9
6.8
8.6
9.6
(1) Optimal EQ setting should be determined via simulation and prototype verification.
(2) Equalization boost values are inclusive of package loss.
(3) To program EQ Level 1-4 correctly in Pin Mode, RESERVED3 and AD2 pins must be tied via 1 kΩ resistor to GND.
dB at
6 GHz
3.0
7.4
8.9
9.8
Table 5. Output Voltage Settings⁽¹⁾
LEVEL
--
1
2
3
4
5
6
--
VODA1
VODB1
--
0
0
0
R
F
1
--
VODA0
VODB0
--
0
R
1
F
R
0
--
VOD - 3 bits[2:0]
000'b
001'b
010'b
011'b
100'b
101'b
110'b
111'b
VOD_DB - 3
bits[2:0]
000'b
000'b
000'b
000'b
000'b
000'b
000'b
000'b
VID Vp-p
1.2
1.2
1.2
1.2
1.2
1.2
1.2
1.2
VOD/VID Ratio⁽¹⁾
0.57 ⁽²⁾
0.65
0.71
0.77
0.83
0.90
1.00
1.04^{(2) (3)}
(1) For 40G-CR4/KR4/SAS/SATA/PCIe operation, it is important to keep the output amplitude and dynamic range as large as possible.
When operating in Pin Mode, it is recommended to use VODA[1:0] = VODB[1:0] = Level 6. In SMBus Mode, it is also recommended to
use Level 6 (that is, VOD = 110'b and VOD_DB = 000'b).
(2) These VOD settings are only accessible via SMBus Modes.
(3) VOD = 111'b setting in SMBus Mode is not recommended.
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