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

4 Multi-Channel Output Architectures

In principle, there are three common architectures for Multi-channel AOUT modules.

  1. Fully integrated DAC: this approach offers the smallest area and possibly the highest performance for the highest cost per channel as this approach requires high voltage DAC.
  2. Low-voltage DAC plus an output buffer: this approach provides scalability regarding number of channels, and flexibility in choosing the DAC and the buffer features at lower cost than the integrated design.
  3. Track and hold multiplexed single channel DAC: this approach offers the lowest cost per channel in the expense of more complex design as channel sequencing needs an MCU. This implementation generally has longer settling time, and higher noise than the other implementations.

Choosing the designed for architecture is a function of the performance, cost, and speed targets

Table 4-1 Multi-Channel AOUT Architectures
Fully integrated DAC Voltage DAC+ buffer stage Multiplexed Track&Hold
Block diagram
Features High integration, accuracy, smaller area but Higher cost per channel Scalable in performance and number of channels and low cost per channel but larger area Lowest cost per channel, but requires MCU and complex design and slower settling
Devices DAC8775, DAC8140x DAC8050x, XTR111, XTR305, TLV9302, OPA2990S DAC80501+TMUX1108/4, DAC8760+TMUX6208