MAX3669EVKIT+ Maxim Integrated, MAX3669EVKIT+ Datasheet - Page 2

• Manufacturer Part Number: MAX3669EVKIT+
• Description: Laser Drivers +3.3V 622Mbps SDH/SONET Laser Driver with Current Monitors and APC
• Manufacturer: Maxim Integrated
• Type: Laser Driverr

Specifications of MAX3669EVKIT+

• Data Rate: 622 Mbps
• Operating Supply Voltage: 3.14 V to 5.5 V
• Supply Current: 40 mA
• Maximum Power Dissipation: 929 mW

In the electrical configuration, an APC test circuit is
included to emulate a semiconductor laser with a moni-
tor photodiode. Monitor diode current is provided by
Q1, which is controlled by an operational amplifier (U3).
The APC test circuit, consisting of U3 and Q1, applies
the simulated monitor diode current to the MAX3669’s
MD pin. The ratio of I
ensure proper operation in the electrical configuration,
set up the evaluation board as follows:
1) Verify inductor L2 is not installed.
2) Remove the shunt from P1 to enable the output.
Note: When performing the following resistance
checks, manually set the ohmmeter to a high range to
avoid forward biasing the on-chip ESD protection
diodes.
3) Adjust R14, the MOD (R
4) Adjust R15, the BIAS (R
5) Adjust R16, the APC (R
6) Power up the board with a +3.3V supply.
7) Apply a differential input signal (max amplitude
8) Attach a high-speed oscilloscope with 50
9) Adjust R
10) Adjust R
Note: See Adjustment and Control Descriptions.
MAX3669 Evaluation Kit
2
10k
and ground).
10k
and ground).
10k
and ground).
to J5.
desired laser-bias current is achieved (refer to the
note in the Applications Information section of the
MAX3669 data sheet).
lation current is achieved.
_______________________________________________________________________________________
800mV per side) to J1 and J2 (DATA+ and DATA-).
resistance between pins 2 and 3 (test point 5
resistance between pins 2 and 3 (test point 4
resistance between pins 2 and 3 (test point 6
BIASMAX
MODSET
(R14) until the desired laser-modu-
(R15) and R
BIAS
Electrical Setup (Default)
/ I
BIASMAX
MODSET
APCSET
MD
is R24 / R23 = 100. To
APCSET
) potentiometer, for
) potentiometer, for
) potentiometer, for
Quick Start
(R16) until the
inputs
For optical operation, the electrical APC test circuit
must be disabled. For optical evaluation of the MAX3669,
configure the EV kit as described in Component
Modifications for Optical Configuration:
1) Remove the shunt from P1 to enable the output.
2) Connect a TO-style header laser and monitor diode
Note: When performing resistance checks, manually
set the ohmmeter to a high range to avoid forward bias-
ing the on-chip ESD protection diodes.
3) Adjust R14, the MOD (R
4) Adjust R15, the BIAS (R
5) Adjust R16, the APC (R
6) Power up the board with a +3.3V supply.
7) Apply a differential input signal ( 800mV per side)
8) Attach the laser-diode output to an optical/electrical
9) Adjust R15 until LED D1 is no longer illuminated.
10) Adjust R14 until the desired optical amplitude is
(Figure 1) as follows:
• Keeping the leads to the laser diode as short as
• Connect the monitor diode on the underside of the
maximum resistance between pins 2 and 3 (test
point 5 and ground).
maximum resistance between pins 2 and 3 (test
point 4 and ground).
desired optical power. (Refer to the Design
Procedure section of the MAX3669 data sheet.)
to J1 and J2 (DATA+ and DATA-).
converter.
Laser power can be monitored at the laser diode
with an optical/electrical converter (refer to the note
in the Applications Information section of the
MAX3669 data sheet).
achieved. Optical amplitude can be observed on an
oscilloscope connected to an optical/electrical con-
verter.
possible, connect the laser diode on the compo-
nent side of the board between R20 and V
with the cathode connected to R20 and the
anode connected to V
the board with the anode connected to the
MAX3669’s MD pin and the cathode connected to
V
CC
.
CC
BIASMAX
MODSET
APCSET
.
) potentiometer, for
) potentiometer, for
) potentiometer, for
Optical Setup
CC