MAX3736 Evaluation Kit Evaluates: MAX3736 General Description Features The MAX3736 evaluation kit (EV kit) is an assembled Single +3.3V Power-Supply Operation demonstration board that provides complete optical eval- AC-Coupling Provided On-Board uation of the MAX3736 3.3V multirate laser driver. Allow s Optical Evaluation The EV kit is composed of an optical test circuit. The output Proven PCB Layout of the optical evaluation section is configured for attach- ment to a laser/monitor diode that is configured in the Fully Assembled and Tested standard four-lead laser connection on BOSA packages. Ordering Information appears at end of data sheet. Optical Evaluation Component List DESIGNATION QTY DESCRIPTION DESIGNATION QTY DESCRIPTION C1, C11, C15, 0.1F 10% ceramic capacitors R1, R2 2 1.5k 5% resistors (0402) 5 C16, C20 (0402) R3 1 75 5% resistor (0402)* Not installed, ceramic capacitors C2C4 0 R4, R18 2 1.0k 1% resistors (0402) (0402) R15, R17 2 20k variable resistors 220pF 10% ceramic capacitors C5, C6 2 (0402)* R21 1 10 5% resistor (0402) 1F 10% ceramic capacitor R22 1 24 5% resistor (0402)* C7 1 (0805) R23 1 15 5% resistor (0402) 0.01F 5% ceramic capacitors C17, C23 2 3.3V multirate laser driver (0402) U2 1 (16 TQFN-EP*) D1 0 Not installed, user-supplied laser Maxim MAX3736ETE+ J1, J2 2 SMA connectors, tab contact 3 Shunts J8, J10, PCB: MAX3736 EVALUATION 12 Test points 1 TP1TP10 KIT REV C JU1, JU2, JU13 3 2-pin headers, 0.1in centers *EP = Exposed pad. Ferrite beads (0402) L1, L3 2 Murata BLM15HG102 *These components are part of the compensation network, which can reduce overshoot and ringing. Ringing due to parasitic series inductance of the laser can be eliminated with R22/R3 and C6/C5. Starting values for most coaxial lasers is R3 = 75 in series with C5 = 220pF and R22 = 24 in series with C6 = 220pF. These values should be experimentally adjusted until the optical eye diagram is optimized. Component Supplier SUPPLIER PHONE WEBSITE Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com Note: Indicate that you are using the MAX3736 when contacting this component supplier. 19-6510 Rev 0 11/12MAX3736 Evaluation Kit Evaluates: MAX3736 6) Conn ect a 3.3V supply between J8 (V ) and J10 CC QuickStart (GND). Set the current limit to 200mA and power on Procedure the device. For optical evaluation of the device, configure the EV kit 7) Adjust R15 (R ) until the desired average BIASSET as follow s: optical power is achieved. 1) To enable the outputs, connect DIS to GND by placing 8) The BIAS current can be monitored at TP8 (V ) BC MON a shunt across jumper JU13. using the follow ing equation: 2) The EV kit is designed to allow connection to a typical V BC MON BOSA-packaged laser. Connect the laser with monitor I 85 BIAS diode (Figure 1) as follows: 1000 Keeping its lead s as short as possible, connect the Note: If the voltage at TP8 exceeds 1.39V, the BC MON laser diode to the appropriate pads in the cut-out pin goes out of regulation. portion on the top (component) side of the PCB. 9) Adjust R17 (R ) until the desired optical ampli- MODSET Note: When performing the following resistance checks, tude is achieved. Optical amplitude can be observed manually set the ohmmeter to a high range to avoid on an oscilloscope connected to an optical-to-elec- forward biasing the on-chip ESD protection diodes. trical converter. Laser oversho ot and ringing can be 3) Adjust R17, the R potentiometer, for maxi- MODSET improved by appropriate selection of R3, R21R23, mum resistance (20k) between TP7 and ground. C5, and C6, as described in the Design Procedure This sets the modulation current to a low value section in the MAX3736 IC data sheet. (< 10mA). Refer to the Design Procedure section in Note: External DACs can be used to control the bias the MAX3736 IC data sheet. and modulation current. To do this, remove shunts from 4) Apply a differential input signal (200mV to P-P jumpers JU1 and JU2 to disconnect potentiometers 2400mV ) between SMA connectors J1 and J2 P-P R15 (R ) and R17 (R ). Connect the BIASSET MODSET (IN+ and IN-). DAC outputs to TP6 (BIASSET) and TP7 (MODSET). 5) Attach the laser diode fiber connector to an optical-to- electrical converter. Table 1. Adjustment and Control Descriptions (see the Quick Start section first) DESIGNATION NAME DESCRIPTION JU13 DIS Enables/disables the output currents. Active low (shunt across JU13 to enable output currents). R15 R Adjusts the bias current. BIASSET R17 R Adjusts the laser modulation current. MODSET TP8 offers a connection to probe the BC MON current through a 1k resistor to ground. TP8 BC MON This allows the bias current to be determined as I = V /1000 x 85. BIAS BC MON TP9 BIAS TP9 allows the voltage at the BIAS pin to be monitored. TP10 offers a connection to probe the monitor diode current through a 1k resistor to ground. TP10 MD The current can be determined as I = V /1000. MD MD Maxim Integrated 2 www.maximintegrated.com =