SLVS905B December   2008  – July 2024 TLV431A-Q1 , TLV431B-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
    1.     Pin Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Thermal Information
    4. 5.4 Recommended Operating Conditions
    5. 5.5 Electrical Characteristics for TLV431A-Q1
    6. 5.6 Electrical Characteristics for TLV431B-Q1
    7. 5.7 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 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 Open Loop (Comparator)
      2. 7.4.2 Closed Loop
  9. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Comparator with Integrated Reference (Open Loop)
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Basic Operation
          2. 8.2.1.2.2 Overdrive
          3. 8.2.1.2.3 Output Voltage and Logic Input Level
            1. 8.2.1.2.3.1 Input Resistance
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Shunt Regulator/Reference
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Programming Output/Cathode Voltage
          2. 8.2.2.2.2 Total Accuracy
          3. 8.2.2.2.3 Stability
        3. 8.2.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.2.1.2.3 Output Voltage and Logic Input Level

For the TLV431 to properly be used as a comparator, the logic output must be readable by the receiving logic device. This is accomplished by knowing the input high and low level threshold voltage levels, typically denoted by VIH & VIL.

As seen in Figure 8-3, TLV431's output low level voltage in open-loop/comparator mode is ~1 V, which is sufficient for some 3.3V supplied logic. However, would not work for 2.5V and 1.8V supplied logic. In order to accommodate this a resistive divider can be tied to the output to attenuate the output voltage to a voltage legible to the receiving low voltage logic device.

TLV431's output high voltage is approximately Vsup due to TLV431 being open-collector. If Vsup is much higher than the receiving logic's maximum input voltage tolerance, the output must be attenuated to accommodate the outgoing logic's reliability.

When using a resistive divider on the output, be sure to make the sum of the resistive divider (R1 & R2 in Figure 8-2) is much greater than Rsup to not interfere with TLV431's ability to pull close to Vsup when turning off.