ONET1131EC
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ZHCSFG0 –SEPTEMBER 2016
7.6.3.6 TX Register 15 (offset = 0000 0000) [reset = 0h]
Figure 36. TX Register 15
7
6
5
4
3
2
1
0
TXBIAS9
R/W
TXBIAS8
R/W
TXBIAS7
R/W
TXBIAS6
R/W
TXBIAS5
R/W
TXBIAS4
R/W
TXBIAS3
R/W
TXBIAS2
R/W
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 13. TX Register 15 Field Descriptions
Bit
7
Field
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
Description
TXBIAS9
TXBIAS8
TXBIAS7
TXBIAS6
TXBIAS5
TXBIAS4
TXBIAS3
TXBIAS2
0
0
0
0
0
0
0
0
Bias current settings (8MSB; 2LSBs are in register 16)
Closed loop (APC):
Coupling ratio CR = IBIAS / IPD, TXBIAS = 0..1023, IBIAS ≤ 150 mA:
TXPDRNG = 00; IBIAS = 0.75 μA x CR x TXBIAS
TXPDRNG = 01; IBIAS = 1.5 μA x CR x TXBIAS
TXPDRNG = 1X; IBIAS = 3 μA x CR x TXBIAS
6
5
4
3
Open Loop:
IBIAS ~ 147 μA x TXBIAS in source mode
IBIAS ~ 147 μA x TXBIAS in sink mode
2
1
0
7.6.3.7 TX Register 16 (offset = 0000 0000) [reset = 0h]
Figure 37. TX Register 16
7
6
5
4
3
2
1
0
Reserved
R/W
TXDMONP
R/W
TXDMONB
R/W
Reserved
R/W
TXBIAS1
R/W
TXBIAS1
R/W
R/W
R/W
LEGEND: R/W = Read/Write; R = Read only; -n = value after reset
Table 14. TX Register 16 Field Descriptions
Bit
Field
Type
Reset
Description
7
Reserved
R/W
0
Reserved
Digital photodiode current monitor selection bit (MONP)
6
5
TXDMONP
TXDMONB
R/W
R/W
0
0
1 = Digital photodiode monitor is active (no external resistor is needed)
0 = Analog photodiode monitor is active (external resistor is required)
Digital bias current monitor selection bit (MONB)
1 = Digital bias current monitor is active (no external resistor is needed)
0 = Analog bias current monitor is active (external resistor is required)
4:2
1
Reserved
TXBIAS1
TXBIAS0
R/W
R/W
R/W
0
0
0
Reserved
Laser Bias current setting (2 LSBs)
0
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