High-Precision DAC Signal Buffer
Created: Jun 01, 2017
No description available.
Sometimes, digital electronic circuits need to isolate logic gates from each other, or they need to drive or switch higher than normal loads, such as relays, solenoids and lamps without the need for inversion. In these cases, impedance of one circuit may affect impedance of another. This reference design features the industry's first zero-crossover and zero-drift amplifier (OPA388) to buffer the analog output of a digital-to-analog converter (DAC). It demonstrates the importance of the zero-crossover and zero-drift feature and how they can minimize the integral nonlinearity (INL) of the system as well as make use of the full-scale range of the DAC (DAC8830).
This design features a precision voltage-output digital-to-analog converter (DAC) that provides excellent linearity and a buffered output with different precision operational amplifiers. This circuit demonstrates the importance of having an op amp with zero-crossover and zero-drift to minimize the integral nonlinearity (INL) of the system, giving a precision analog output. The design provides a solution of linearization throughout the full scale range of the DAC using a zero-crossover, zero-drift device as the buffered output. This design uses OPA388IDR, which is an ultra-low-noise, zero-drift, zero-crossover, rail-to-rail input and output op amp. These devices operate from 1.8 to 5.5 V, excellent AC performance, and only 0.25μV of offset and 0.005μV/°C of drift over temperature. The OPA340 device operates on a single supply as low as 2.5 V with an input common-mode voltage range that extends 500 mV below ground and 500 mV above the positive supply. The REF5050 is a low-noise, low-drift, very high precision voltage reference. This reference is capable of both sinking and sourcing current, and has excellent line and load regulation.
This design can be used in field transmitter, data acquisition systems, wireless infrastructure, and also in test and measurement applications.