An accurate current source with on-chip self-calibration circuits for low-voltage differential transmitter drivers

An accurate CMOS current source for current-mode low-voltage differential transmitter drivers has been designed and fabricated. It is composed of binary weighted current mirrors with built-in switch-cap based self-calibration circuits. Experimental results show that it achieves the specified ±1% accuracy with 16% reference current variation, 42% power supply variation, 10% load variation, and CMOS process variation respectively.