MAX3646 Maxim Integrated Products, MAX3646 Datasheet - Page 6

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

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155Mbps to 622Mbps SFF/SFP
Laser Driver with Extinction Ratio Control
6
2, 5, 14,
10, 12
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PIN
EP
17
11
13
15
16
18
19
20
21
22
23
24
1
3
4
6
7
8
9
MODBCOMP
Exposed Pad
MODTCOMP
TX_DISABLE
SHUTDOWN
TX_FAULT
APCFILT1
APCFILT2
TH_TEMP
PC_MON
BC_MON
MODSET
APCSET
NAME
OUT+
OUT-
GND
BIAS
V
IN+
MD
IN-
CC
Modulation-Current Compensation from Temperature. A resistor at this pin sets the temperature
coefficient of the modulation current when above the threshold temperature. Leave open for zero
temperature compensation.
+3.3V Supply Voltage
Noninverted Data Input
Inverted Data Input
Transmitter Disable, TTL. Laser output is disabled when TX_DISABLE is asserted high or left
unconnected. The laser output is enabled when this pin is asserted low.
Photodiode-Current Monitor Output. Current out of this pin develops a ground-referenced voltage
across an external resistor that is proportional to the monitor diode current.
Bias-Current Monitor Output. Current out of this pin develops a ground-referenced voltage across an
external resistor that is proportional to the bias current.
Shutdown Driver Output. Voltage output to control an external transistor for optional shutdown
circuitry.
Ground
Open-Collector Transmit Fault Indicator
Laser Bias-Current Output
Inverted Modulation-Current Output. I MOD flows into this pin when input data is low.
Noninverted Modulation-Current Output. I MOD flows into this pin when input data is high.
Monitor Photodiode Input. Connect this pin to the anode of a monitor photodiode. A capacitor to
ground is required to filter the high-speed AC monitor photocurrent.
Connect a capacitor (C APC ) between pin 19 (APCFILT1) and pin 20 (APCFILT2) to set the dominant
pole of the APC feedback loop.
(See Pin 19)
A resistor connected from this pin to ground sets the desired average optical power.
A resistor connected from this pin to ground sets the desired constant portion of the modulation
current.
Modulation-Current Compensation from Bias. Couples the bias current to the modulation current.
Mirrors I BIAS through an external resistor. Leave open for zero-coupling.
Threshold for Temperature Compensation. A resistor at this pin programs the temperature above
which compensation is added to the modulation current.
Ground. Solder the exposed pad to the circuit board ground for specified thermal and electrical
performance.
(Table
FUNCTION
1)
Pin Description