A 1.5-ns Switching Time, 9-Bit Current-Mode DAC for High Speed Laser Diode Drivers

Evolution in consumer electronics has brought the need for high-current laser diode drivers (LDDs) compatible with integrated systems on chip (SOCs). Traditional solutions device-based are migrating to integrated architectures granting easy digital control, compliance to the voltage rails and fast switching times. The introduction of the digital control directly implies the need of digital-to-analog converter (DAC) structures for the modulation of the laser current and the chosen solution has to match the analog performances required for the particular application. This paper presents a current-mode DAC architecture for LDDs together with a 9-bit implementation which targets a rise time of 1.5 ns for a zero-to-full-current (51 mA) switching condition. A 0.105-mm2 prototype has been manufactured in a 130-nm BiCMOS technology, and the experimental measurements are reported.