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General Description
The GD19903 is a high-speed amplifier,
which provides a high power output drive
suitable to feed an optical modulator at
10 Gbit/s.
GD19903 provides single-ended or differ-
ential output drive to an external modula-
tor. The outputs must be externally AC
coupled, and on-chip termination is pro-
vided to minimize reflections.
The output amplitude can be adjusted to
the required value by sourcing a DC cur-
rent into a control terminal of the device.
The data outputs can be shut down by
setting the amplitude control currents to
0. When shut down, the residual output
data amplitude will be less than 1.5 % of
maximum amplitude.
The GD19903 modulator driver provides
Amplitude Modulation
(AM) control of the
outputs of the modulator driver for control
of the modulation in Mach-Zehnder
modulators. The AM will be controlled by
inserting a dither current at up to 10 kHz
with AM amplitude of up to 10 % of the
data amplitude.
An analogue monitor output is provided
to indicate peak-peak output voltage
swing.
The GD19903 modulator driver is deli-
vered in a 68 pin ceramic package. 50
transmissions lines inside the package
are ensured by GIGA proprietary
Flexguide technology.
Advance Information
Features
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Fully differential, 10 V
PP
differential
drive capability.
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CML inputs.
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Limiting structure.
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Output peak-peak monitor.
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Data outputs can be turned off.
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Capability to AM modulate output.
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Power supply: -8.0 V and +5 V
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No external choke required.
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Maximum rise/fall time of 45 ps
(20 – 80 %).
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Power dissipation: 8.6 W (typical) at
maximum output swing.
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Package: 68 pin MLC
Applications
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Telecommunications transmission
systems:
–
SDH STM-64
–
SONET OC-192
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WDM applications.
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10 Gbit/s optical transmission.
10 Gbit/s
Modulator Driver
GD19903
D
VMONREF
VMON
VOUT
VIN
VINN
VOUTN
VEE
VCC
I
I