Dual-Slope ADC Boosts DMM's Precision

Low linearity errors of typically 0.001% full scale, 10 mW total power dissipation, 2 pA input current at 0V and a ±3.5V input range are all features of the ALD500 Series of front-end, dual-slope ADCs. The 18-bit integrating converters offer true 4-1/2-digit to 5-1/2-digit display resolution for a variety of high-accuracy, line-powered and portable digital multimeter applications.The devices operate from ±5V power supplies and offer resolution of up to 18 bits with sign bit and over-range bit. They incorporate a 1-µs zero-crossing comparator and dissipate 6 mW typical.