J_EP and J_EN: These two SMA connectors are for the positive (EP) and negative (EN) LVDS inputs of the device, respectively. By default, both connectors are terminated with 50Ω resistors to match source impedance of the instruments. If the device must be driven by an LVDS drive that requires 100Ω termination, remove R22. Alternatively, to operate the device and the EVM on a single-ended input, short jumper J1 and remove R10. This configuration biases the EN pin to midsupply. A single-ended signal with a voltage level that crosses the midsupply voltage can then be provided to the EP pin to switch the device output current.

J_VSET: This SMA connector is used to provide voltage to the VSET pin of the device, and thus sets the current value at the output. Apply an appropriate voltage between 0.2V to 2V to this connector to control IOUT. Alternatively, remove R20 and connect R11 to control the voltage at VSET from the onboard resistor divider by adjusting potentiometer R8.

J_PD: This SMA connector connects to the power-down pin (PD) of the device. To power down the device, pull the PD pin to greater than AVDD – 1.2V. To enable the device, pull the PD pin voltage to less than AGND + 1.2V.

J_TIA_OUT: The onboard TIA (U2) outputs to this SMA connector. The TIA senses current from the back facet diode of the laser and converts the current to a voltage-level based on the gain set by R12.