1.0625Gbps to 11.3Gbps, SFP+ Laser Driver
with Laser Impedance Mismatch Tolerance
18 17 16 15 14 13
12 3 4 56
(4mm × 4mm)
*EXPOSED PAD CONNECTED TO GROUND.
Power Supply. Provides supply voltage to the digital block.
Disable Input, CMOS Input. Set to logic-low for normal operation. Logic-high or open disables both
the modulation current and the bias current. Internally pulled up by a 7.5kI resistor to VCC.
Fault Output, Open Drain. Logic-high indicates a fault condition. FAULT remains high even after the
fault condition has been removed. A logic-low occurs when the fault condition has been removed and
the fault latch has been cleared by toggling the DISABLE pin. FAULT should be pulled up to VCC by
a 4.7kI to 10kI resistor.
Analog Laser Bias-Current Limit. A resistive voltage-divider connected among BMON, BMAX, and
BMAX ground sets the maximum allowed laser bias current limit. The voltage at BMAX is internally com-
pared to 1.2V bandgap reference voltage.
6, 7, 12, 13
Bias Current-Monitor Output. Current out of this pin develops a ground-referenced voltage across
external resistor(s) that is proportional to the laser bias current. The current sourced by this pin is
typically 1/100th the BIAS pin current.
Power Supply. Provides supply voltage to the output block.
Inverted Modulation Current Output. Internally pulled up by a 25I resistor to VCCT.
Noninverted Modulation Current Output. Internally pulled up by a 25I resistor to VCCT.
Laser Bias Current Connection
Chip-Select Input, CMOS. Setting CSEL to logic-high starts a cycle. Setting CSEL to logic-low ends
the cycle and resets the control state machine. Internally pulled down by a 75kI resistor to ground.
Serial-Data Bidirectional Input, CMOS. Open-drain output. This pin has a 75kI internal pullup, but it
requires an external 4.7kI to 10kI pullup resistor. (Data line-collision protection is implemented.)