CMOS 155-Mb/s optical wireless transmitter for indoor networks

12 A 155 Mb/s CMOS LED driver for low-cost optical wireless links is presented. The driver is realized in a 0.7 micrometers commodity mixed-signal CMOS process from Alcatel Microelectronics. The driver employs switching transistors which drive a current mirror to generate modulation current. The circuit also contains a controllable quiescent current source. The transmitter driver incorporates two novel features: adjustable current peaking and adjustable charge extraction. These functions are implemented with the use of original timing generators. Simulations indicate that the design achieves output rise times and fall times of less than 2 ns. Other design parameters were selected to suit the requirements of the InP resonant cavity LED that was developed for this application.