GD90521 Intel, GD90521 Datasheet - Page 2

• Manufacturer Part Number: GD90521
• Manufacturer: Intel

Specifications of GD90521

• Lead Free Status / Rohs Status: Not Compliant

Functional Details
Data and Clock Inputs
The differential data input (SDIP/SDIN) is AC coupled from the
signal source via connectors J2/J3. The inputs are DC-biased
and terminated internally in the GD16521. Only external de-
coupling of the termination pins (TDIP/TDIN) is required.
The clock input (SCIP/SCIN) is constructed in the same way as
the data input.
Data Output
Each branch of the differential data output (IM/IMB) terminates
in two output pins. Connecting each of these two output pins re-
sults in a 25 W characteristic impedance. The single-ended load
is connected to IM, and both outputs are termianted in the same
manner to ensure symmetrical working conditions for the driver.
The IM output is AC coupled to the load via C26. DC bias is in-
jected through L1 – L2. The unused branch is DC biased via L3
– L4 and is AC coupled to a dummy load (R36). The load (la-
ser-diode) is pre-biased via L5 – L6 from the IB pin. The output
is either connected to the SMA connector (J6) or to a sur-
face-mounted, laser.
If a laser is mounted, the signal from the monitor diode is fed
back to the integrated regulation circuits (AR and PD), which
are described in the GD16521 data sheet. The modulation cur-
rent can be adjusted on the potentiometer (P3). The integrated
regulation circuit for control of the modulation current is de-
scribed in the GD16521 data sheet.
The output from the integrated mark/space monitor is filtered
and buffered with offset adjustment in an LMV358 op-amp
(U4:B) and fed to a test point.
DIP Switches
Two DIP switches are available for control of re-timing/bypass
and shutdown function.
Default settings are:
u
u
Other Items
The power supply for the laser’s anode is as default connected
to VCC. However the PCB is designed with separate access to
this power supply. By removing of R39 the laser can be
powered from a separate (higher) voltage if desired. Hence
tests can be made with the laser DC connected without modifi-
cation of the PCB.
Data Sheet Rev.: 3
Re-timing: Enabled
Shutdown: Disabled
GD90521
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