Abstract :
This 10-bit monolithic D/A converter is priced as low as $9.95 for units with a maximum error (relative to full-scale output current) down to ±0.05 percent. The low-cost and high-accuracy features are attributed to a laser ¿zapping¿ process introduced during the wafer probe step of the production cycle. With the new process, the chip is designed with parallel resistive structures for all critical resistance values. These parallel structures are linked at a number of points by ¿shorting bars.¿ During the wafer-probe process, the output of each chip is measured and, if the accuracy is out of specification, a computer-monitored laser beam zaps the sequential shorting bars until the desired accuracy is obtained.