10-bit Driver IC Using 3-bit DAC Embedded Operational Amplifier for Spatial Optical Modulators (SOMs)

A 10-bit driver IC for laser projection full high-definition TV (HDTV) applications using a spatial optical modulator (SOM) has been developed. For high-speed data transfer between the timing controller and driver IC, the driver IC adopts a mini-LVDS interface that operates up to 400 Mbps. To reduce the chip area, a digital-to-analog converter (DAC) structure including a 7-bit resistor-string DAC and a unity-gain buffer, which has a 3-bit linear DAC, is proposed. The area of the proposed DAC is 40% smaller than that of the typical 8-bit resistor-string DAC. The driver IC, which has 546 channels, is fabricated using a 0.35-mum CMOS process, and its area is 21 700 mum times 3 000 mum. The measured INL and DNL of the output voltages are less than 0.13 LSB, and the settling time is 1.93 mus with 40 pF capacitive loads. The output voltage deviation of the driver IC is achieved as 1.3 mV by compensating the nonuniformity among output channels.