MAX3646 Maxim Integrated Products, MAX3646 Datasheet - Page 9

• Manufacturer Part Number: MAX3646
• Description: 155Mbps to 622Mbps Sff/sfp Laser Driver
• Manufacturer: Maxim Integrated Products

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Figure 5. Simplified Safety Circuit
Table 1. Typical Fault Conditions
1
2
3
4
If any of the I/O pins are shorted to GND or V
exceeds the programmed threshold.
End-of-life (EOL) condition of the laser diode. The bias current and/or the photocurrent exceed the programmed threshold.
Laser cathode is grounded and photocurrent exceeds the programming threshold.
No feedback for the APC loop (broken interconnection, defective monitor photodiode), and the bias current exceeds the
programmed threshold.
R
R
PC_MON
BC_MON
Laser Driver with Extinction Ratio Control
TX_DISABLE
PC_MON
BC_MON
_______________________________________________________________________________________
V
CC
I
I
BIAS
MD
82
1
POR AND COUNTER
V
V
60ms DELAY
60ms DELAY
CC
CC
COUNTER
MOD CURRENT
APC CURRENT
EXCESSIVE
EXCESSIVE
SETPOINT
SETPOINT
V
V
REF
REF
155Mbps to 622Mbps SFF/SFP
CC
(single-point failure; see Table 2), and the bias current or the photocurrent
S
R
LATCH
RS
100ns DELAY
Q
I
ENABLE
I
ENABLE
MOD
BIAS
SHUTDOWN
TX_FAULT
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