SBAA631 January   2025 DAC80508 , INA592 , XTR111 , XTR300 , XTR305

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Analog Output Module Specification
  6. 3Analog Output Module Structure
  7. 4Multi-Channel Output Architectures
    1. 4.1 Fully Integrated DAC Architecture
    2. 4.2 Low Voltage DAC Plus an Output Buffer
    3. 4.3 Track and Hold Multiplexed Output
  8. 5Single-Channel Output Architectures
    1. 5.1 Fully Integrated DAC
    2. 5.2 Low-Voltage DAC Plus an Output Buffer
    3. 5.3 Pulse-Width Modulation Plus a Buffer
  9. 6Output Buffers
    1. 6.1 Unidirectional Current Buffer
    2. 6.2 Bidirectional Current Buffer
    3. 6.3 Voltage Buffer
    4. 6.4 Combined Voltage or Current Buffer
  10. 7Summary
  11. 8References

6.3 Voltage Buffer

Voltage buffer is simpler and straightforward and provides the required gain for low-voltage DAC signal to reach ±10V. According to the available supply and the maximum output voltage, rail-to-rail output op amp is not be needed. Low offset voltage is important for achieving high accuracy. Precision matched resistors with low drift are required for precise gain.

Voltage Buffer Voltage BufferFigure 6-3 Voltage Buffer

Inverting difference amplifier can be used as in Figure 6-3, which enables the use of matched resistors readily available. The inverting amplifier input impedance is finite, designer need to make sure the DAC can drive the selected resistors.

The second implementation shown in Figure 6-3 is the non-inverting summing amplifier. The amplifier has high input impedance, but requires precision resistors, and possibly needs calibration. The amplifier allows also for the use of lower than 5V DAC.