Datasheet TL431LI, TL432LI (Texas Instruments) - 10

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TL431LI TL432LI
SLVSDQ6A – JULY 2018 – REVISED NOVEMBER 2018
www.ti.com 8.2 Dynamic Impedance
' K V A K Z A The dynamic impedance is defined as: ' K I A . When the device is operating with two external resistors 'V z ' (see Figure 15), the total dynamic impedance of the circuit is given by: 'I which is approximately equal to § R1 · K Z A ¨1 ¸ © R2 ¹ . The VKA of the TL431LI can be affected by the dynamic impedance. The TL431LI test current Itest for VKA is specified on the Eletrical Characteristics . Any deviation from Itest can cause deviation on the output VKA. Figure 17 shows the effect of the dynamic impedance on the VKA. ) (mA A I I K test / P IKA IKA(min) 0 VKA (V) Ps
Figure 17. Dynamic Impedance
10 Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated Product Folder Links: TL431LI TL432LI Document Outline 1 Features 2 Applications 3 Description Table of Contents 4 Revision History 5 Device Comparison Table 6 Pin Configuration and Functions 7 Specifications 7.1 Absolute Maximum Ratings 7.2 ESD Ratings 7.3 Thermal Information 7.4 Recommended Operating Conditions 7.5 Electrical Characteristics 7.6 Typical Characteristics 8 Parameter Measurement Information 8.1 Temperature Coefficient 8.2 Dynamic Impedance 9 Detailed Description 9.1 Overview 9.2 Functional Block Diagram 9.3 Feature Description 9.4 Device Functional Modes 9.4.1 Open Loop (Comparator) 9.4.2 Closed Loop 10 Applications and Implementation 10.1 Application Information 10.2 Typical Applications 10.2.1 Comparator With Integrated Reference 10.2.1.1 Design Requirements 10.2.1.2 Detailed Design Procedure 10.2.1.3 Application Curve 10.2.2 Precision Constant Current Sink 10.2.2.1 Design Requirements 10.2.2.2 Detailed Design Procedure 10.2.3 Shunt Regulator/Reference 10.2.3.1 Design Requirements 10.2.3.2 Detailed Design Procedure 10.2.3.3 Application Curve 10.2.4 Isolated Flyback with Optocoupler 10.2.4.1 Design Requirements 10.3 System Examples 11 Power Supply Recommendations 12 Layout 12.1 Layout Guidelines 12.2 Layout Example 13 Device and Documentation Support 13.1 Related Links 13.2 Documentation Support 13.2.1 Device Nomenclature 13.2.2 Related Documentation 13.3 Receiving Notification of Documentation Updates 13.4 Community Resources 13.5 Trademarks 13.6 Electrostatic Discharge Caution 13.7 Glossary 14 Mechanical, Packaging, and Orderable Information