MAX3946EVKIT+ Maxim Integrated, MAX3946EVKIT+ Datasheet - Page 3

• Manufacturer Part Number: MAX3946EVKIT+
• Description: Laser Drivers 1.0625Gbps to 11.3Gbps SFP+ Laser Driver with Laser Impedance Mismatch Tolerance
• Manufacturer: Maxim Integrated
• Type: Laser Driverr

Specifications of MAX3946EVKIT+

• Data Rate: 11.3 Gbps
• Operating Supply Voltage: 2.85 V to 3.63 V
• Supply Current: 68 mA
• Maximum Power Dissipation: 2.2 W

Figure 2. MAX3946 EV Kit Software
The GUI consists of three main blocks: bias and modulation
control, data path adjustments, and fault indicators.
For bias and modulation current there are three controls:
set current, set maximum, and increment. The left-side
data-entry boxes allow the user to write to the SET_IBIAS
or SET_IMOD register directly, as long as that value is
below the value loaded in the IBIASMAX and IMODMAX
registers. The middle data-entry boxes allow the user
to write to the IBIASMAX and IMODMAX registers. The
right-side data-entry boxes allow the user to increment
or decrement the bias and modulation current registers
over a Q15 LSB range by writing to the BIASINC and
MODINC registers. The appropriate Load button must
be clicked to initiate a register write. The Read but-
tons read and display the values held in the SET_IBIAS/
SET_IMOD, IBIASMAX/IMODMAX, and BIASINC/MODINC
registers. Calculated bias and modulation current values
are displayed below the data-entry boxes. The modula-
tion current is calculated based on the laser’s effective
series resistance provided by the user in the Laser
Resistance (Rld) edit box.
Detailed Description of Software
Graphical User Interface (GUI)
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Bias and Modulation Control
MAX3946 Evaluation Kit
This block allows control of preemphasis, the input
equalization, data polarity, and pulse-width adjustment.
The Tx De-emphasis Control edit box has a pull-down
box with four options for setting the TXDE_MD bits in the
TXCTRL register. When manual control is selected, the
De-emphasis edit box becomes available to write values
to the SET_TXDE register. When the Tx Polarity check-
box is checked the TOUT+ pin sinks current when TIN+
is high (typical setup). The output polarity is inverted if
the box is unchecked. Check the Tx Equalizer Enable
checkbox to enable the input equalizer. Once checked,
the Tx EQ Control edit box becomes available to write
to the SET_TXEQ register.
Along the right-hand side of the GUI are fault indica-
tors that show the status of the TXSTAT1 and TXSTAT2
registers. Hard faults disable the device and require a
toggling of the DISABLE checkbox to restart the device
(once the source of the fault has been removed). Soft
faults operate as warnings, but do not disable the part.
Automatic updating of the fault monitors can be enabled
by checking the Auto Read Monitors checkbox.
Data Path Adjustments
Fault Indicators
3