SBOS782A November   2016  – May 2018 TLV170 , TLV2170 , TLV4170

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Smallest Packaging for 36-V Operational Amplifiers
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions: TLV170
    2.     Pin Functions: TLV2170
    3.     Pin Functions: TLV4170
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information: TLV170
    5. 6.5 Thermal Information: TLV2170
    6. 6.6 Thermal Information: TLV4170
    7. 6.7 Electrical Characteristics
    8. 6.8 Typical Characteristics: Table of Graphs
    9. 6.9 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Operating Characteristics
      2. 7.3.2 Phase-Reversal Protection
      3. 7.3.3 Electrical Overstress
      4. 7.3.4 Capacitive Load and Stability
    4. 7.4 Device Functional Modes
      1. 7.4.1 Common-Mode Voltage Range
      2. 7.4.2 Overload Recovery
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 TINA-TI™ (Free Software Download)
        2. 11.1.1.2 DIP Adapter EVM
        3. 11.1.1.3 Universal Op Amp EVM
        4. 11.1.1.4 TI Precision Designs
        5. 11.1.1.5 WEBENCH Filter Designer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2 Detailed Design Procedure

Figure 30 shows a unity-gain buffer driving a capacitive load. Equation 1 shows the transfer function for the circuit in Figure 30. Not shown in Figure 30 is the open-loop output resistance of the op amp, Ro.

Equation 1. TLV170 TLV2170 TLV4170 ai_refdes_eqn_bos618.gif

The transfer function in Equation 1 has a pole and a zero. The frequency of the pole (fp) is determined by (Ro + RISO) and CLOAD. Components RISO and CLOAD determine the frequency of the zero (fz). A stable system is obtained by selecting RISO such that the rate of closure (ROC) between the open-loop gain (AOL) and 1/β is 20 dB per decade; see Figure 31. The 1/β curve for a unity-gain buffer is 0 dB.

TLV170 TLV2170 TLV4170 ai_refdes_bodeplot_bos618.gifFigure 31. TIPD128 Unity-Gain Amplifier With RISO Compensation

ROC stability analysis is typically simulated. The validity of the analysis depends on multiple factors, especially the accurate modeling of Ro. In addition to simulating the ROC, a robust stability analysis includes a measurement of overshoot percentage and ac gain peaking of the circuit using a function generator, oscilloscope, and gain and phase analyzer. Phase margin is then calculated from these measurements. Table 4 shows the overshoot percentage and ac gain peaking that correspond to phase margins of 45° and 60°. For more details on this design and other alternative devices that can be used in place of the TLV170, see the Capacitive Load Drive Solution Using an Isolation Resistor precision design.

Table 4. Phase Margin versus Overshoot and AC Gain Peaking

PHASE MARGIN OVERSHOOT AC GAIN PEAKING
45° 23.3% 2.35 dB
60° 8.8% 0.28 dB