SNOSD26 May   2016 TLV521

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  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
    5. 6.5 Electrical Characteristics
    6. 6.6 AC Electrical Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Input Stage
      2. 7.4.2 Output Stage
  8. 8 Applications and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Driving Capacitive Load
      2. 8.1.2 EMI Suppression
    2. 8.2 Typical Applications
      1. 8.2.1 60-Hz Twin T-Notch Filter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Portable Gas Detection Sensor
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
      3. 8.2.3 High-Side Battery Current Sensing
        1. 8.2.3.1 Design Requirements
        2. 8.2.3.2 Detailed Design Procedure
        3. 8.2.3.3 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
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7 Detailed Description

7.1 Overview

The TLV521 is fabricated with Texas Instruments' state-of-the-art VIP50 process. This proprietary process dramatically improves the performance of Texas Instruments' low-power and low-voltage operational amplifiers. The following sections showcase the advantages of the VIP50 process and highlight circuits which enable ultra-low power consumption.

7.2 Functional Block Diagram

TLV521 Op_Amp_Triangle.gif Figure 29. Block Diagram

7.3 Feature Description

The amplifier's differential inputs consist of a noninverting input (IN+) and an inverting input (IN–). The amplifier amplifies only the difference in voltage between the two inputs, which is called the differential input voltage. The output voltage of the op-amp Vout is given by Equation 1:

Equation 1. VOUT = AOL (IN+ - IN-)

where AOL is the open-loop gain of the amplifier, typically around 100 dB.

7.4 Device Functional Modes

7.4.1 Input Stage

The TLV521 has a rail-to-rail input which provides more flexibility for the system designer. Rail-to-rail input is achieved by using in parallel, one PMOS differential pair and one NMOS differential pair. When the common mode input voltage (VCM) is near V+, the NMOS pair is on and the PMOS pair is off. When VCM is near V−, the NMOS pair is off and the PMOS pair is on. When VCM is between V+ and V−, internal logic decides how much current each differential pair will get. This special logic ensures stable and low distortion amplifier operation within the entire common mode voltage range.

Because both input stages have their own offset voltage (VOS) characteristic, the offset voltage of the TLV521 becomes a function of VCM. VOS has a crossover point at 1.0 V below V+. Refer to the ’VOS vs. VCM’ curve in the Typical Performance Characteristics section. Caution should be taken in situations where the input signal amplitude is comparable to the VOS value and/or the design requires high accuracy. In these situations, it is necessary for the input signal to avoid the crossover point. In addition, parameters such as PSRR and CMRR which involve the input offset voltage will also be affected by changes in VCM across the differential pair transition region.

7.4.2 Output Stage

The TLV521 output voltage swings 3 mV from rails at 3.3-V supply, which provides the maximum possible dynamic range at the output. This is particularly important when operating on low supply voltages.

The TLV521 Maximum Output Voltage Swing defines the maximum swing possible under a particular output load. The TLV521 output swings 50 mV from the rail at 5-V supply with an output load of 100 kΩ.