ONET1191V Datasheet, PDF (18/22 Pages) Texas Instruments – 11.3-GBPS DIFFERENTIAL VCSEL DRIVER

ONET1191V
SLLS750A – AUGUST 2006 – REVISED SEPTEMBER 2006
www.ti.com
Table 7. I_MOD vs I_MODC for a Given Attenuator Pad and VCSEL
I_MODC (mA):
50-Ω PAD
REGISTER SETTING ATTENUATION (dB)
VCSEL SERIES
RESISTANCE (Ω)
I_MOD (mA): MODULATION
CURRENT AT THE VCSEL
40
3
100
14.76
40
6
100
10.52
30
3
100
11.07
30
6
100
7.89
20
3
100
7.38
20
6
100
5.26
40
3
60
18.33
40
6
60
13.12
30
3
60
13.75
30
6
60
9.84
20
3
60
9.17
20
6
60
6.56
LAYOUT GUIDELINES
For optimum performance, use 50-Ω transmission lines (100-Ω differential) for connecting the signal source to
the DIN+ and DIN– pins and for connecting the modulation current outputs, MOD+ and MOD–, to the VCSEL.
The length of the transmission lines should be kept as short as possible to reduce loss and pattern-dependent
jitter.
18
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