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

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

11.2.8 Driving Capacitive Loads

The THS4531 is designed for a nominal capacitive load of 2 pF (differentially). When driving capacitive loads greater than this, it is recommended to use small resisters (RO) in series with the output as close to the device as possible. Without RO, capacitance on the output will interact with the output impedance of the amplifier causing phase shift in the loop gain of the amplifier that will reduce the phase margin resulting in:

1. Peaking in the frequency response.

2. Overshoot, undershoot, and ringing in the time domain response with a pulse or square-wave signal.

3. May lead to instability or oscillation.

Inserting RO will compensate the phase shift and restore the phase margin, but it will also limit bandwidth. The circuit shown in Figure 68 is used to test for best RO versus capacitive loads, CL, with a capacitance placed differential across the VOUT+ and VOUT- along with 2 kΩ load resistor, and the output is measure with a differential probe. Figure 77 shows the optimum values of RO versus capacitive loads, CL, and Figure 78 shows the frequency response with various values. Performance is the same on both 2.7 V and 5 V supply.

THS4531 G068_RO_vs_CLOAD.pngFigure 77. Recommended Series Output Resistor vs Capacitive Load for Flat Frequency Response
THS4531 G069_Gain_vs_Freq_CLOAD.pngFigure 78. Frequency Response for Various RO and CL Values