SBOA591 March   2024 ADS8881 , ADS8900B , ADS9224R , THS4551 , THS4552

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2CWD Block Diagram and Designs
    1. 2.1 Proposal 1
    2. 2.2 Proposal 2
    3. 2.3 Proposal 3
    4. 2.4 Proposal 4
  6. 3Comparison of the Designs
  7. 4Summary
  8. 5References

2.3 Proposal 3

Shown in Figure 2-8, the ADS8900B used in Proposal 3 is a 20 bits SAR ADC with 1 MSPS in TI introduced in 2017, and since the ADS8900B does not have an internal reference, the REF70 is also required as an external reference. The proposal has the highest quality signal-to-noise ratio and dynamic range among the SAR ADC proposals. Designed for high-end ultrasound device CWD applications for higher image quality.

GUID-20240221-SS0I-H8Z5-3VGV-GK5LFCXMWCDN-low.svg Figure 2-8 Proposal 3 ADS8900B and THS4551

Simulation of noise and amplitude frequency characteristics for Proposal 3.

GUID-20240221-SS0I-FBPK-KDKD-TC9JQ1MRHCXD-low.png Figure 2-9 Proposal 3 Simulated Circuit

Proposal 3 noise and amplitude frequency characteristics

GUID-20240221-SS0I-SS4F-GNWT-TCNXJRKVH10J-low.png Figure 2-10 Proposal-3 AC and Noise Performance

As shown from the simulation results of the Proposal 3, the Proposal 3 has the lowest total integral noise, highest signal-to-noise ratio and dynamic range among all of the SAR ADC proposals.