SLOS358C September   2011  – April 2020 THS4531

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1. 2.1 1 kHz FFT Plot on Audio Analyzer
  3. 3 Description
  4. 4 Revision History
  5. 5 Packaging and Ordering Information
  6. 6 Electrical Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 Thermal Information
    3. 6.3 Electrical Characteristics: VS = 2.7 V
    4. 6.4 Electrical Characteristics: VS = 5 V
  7. 7 Device Information
    1. 7.1 PIN Configurations
      1. Table 2. PIN Functions
  8. 8 Table of Graphs
  9. 9 Typical Characteristics: VS = 2.7 V
  10. 10Typical Characteristics: VS = 5 V
  11. 11Application Information
    1. 11.1 Typical Characteristics Test Circuits
      1. 11.1.1 Frequency Response and Output Impedance
      2. 11.1.2 Distortion
      3. 11.1.3 Slew Rate, Transient Response, Settling Time, Overdrive, Output Voltage, and Turn-On and Turn-Off Time
      4. 11.1.4 Common-Mode and Power Supply Rejection
      5. 11.1.5 VOCM Input
      6. 11.1.6 Balance Error
    2. 11.2 Application Circuits
      1. 11.2.1  Differential Input to Differential Output Amplifier
      2. 11.2.2  Single-Ended Input to Differential Output Amplifier
      3. 11.2.3  Differential Input to Single-Ended Output Amplifier
      4. 11.2.4  Input Common-Mode Voltage Range
      5. 11.2.5  Setting the Output Common-Mode Voltage
      6. 11.2.6  Single-Supply Operation
      7. 11.2.7  Low Power Applications and the Effects of Resistor Values on Bandwidth
      8. 11.2.8  Driving Capacitive Loads
      9. 11.2.9  Audio Performance
      10. 11.2.10 Audio On and Off Pop Performance
    3. 11.3 Audio ADC Driver Performance: THS4531 AND PCM4204 Combined Performance
    4. 11.4 SAR ADC Performance
      1. 11.4.1 THS4531 and ADS8321 Combined Performance
      2. 11.4.2 THS4531 and ADS7945 Combined Performance
    5. 11.5 EVM and Layout Recommendations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

11.4.1 THS4531 and ADS8321 Combined Performance

To show achievable performance with a high performance SAR ADC, the THS4531 is tested as the drive amplifier for the ADS8321. The ADS8321 is a 16-bit, SAR ADC that offers excellent AC and DC performance, with ultra-low power and small size. The circuit shown in Figure 88 is used to test the performance. Data was taken using the ADS8321 at 100 kSPS with input frequency of 10 kHz and signal levels 0.5 dB below full scale. The FFT plot of the spectral performance is in Figure 89. A summary of the FFT analysis results are in Table 6 along with ADS8321 typical data sheet performance at fS = 100 kSPS. Please refer to its data sheet for more information.

The standard ADS8321 EVM and THS4531 EVM are modified to implement the schematic in Figure 88 and used to test the performance of the THS4531 as a drive amplifier. With single supply +5 V supply the output common-mode of the THS4531 defaults to +2.5 V as required at the input of the ADS8321 so the VOCM input of the THS4531 simply bypassed to GND with 0.22 µF capacitor. The summary of results of the FFT analysis versus typical data sheet performance shown in Table 6 show the THS4531 will make an excellent drive amplifier for this ADC.

THS4531 THS4531_to_ADS8321_Test_Circuit.gifFigure 88. THS4531 and ADS8321 Test Circuit
THS4531 G078_THS4531_to_ADS8321_10kHz_FFT.pngFigure 89. THS4531 + ADS8321 1-kHz FFT

Table 6. 10 kHz FFT Analysis Summary

CONFIGURATION TONE SIGNAL SNR THD SINAD SFDR
THS4531 + ADS8321 10 kHz -0.5 dBFS 87 dBc -96 dBc 87 dBc 100 dBc
ADS8321 data sheet (typical) 10 kHz -0.5 dBFS 87 dBc -86 dBc 84 dBc 86 dBc