SCBS881F january   2010  – june 2023 TMS3705

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Functional Block Diagram
  6. 5 Revision History
  7. 6 Device Characteristics
    1. 6.1 Related Products
  8. 7 Terminal Configuration and Functions
    1. 7.1 Pin Diagram
    2. 7.2 Signal Descriptions
  9. 8 Specifications
    1. 8.1 Absolute Maximum Ratings #GUID-D01738F0-6DD5-4A5A-BE33-2BC076228CBE/AMR001
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Electrical Characteristics
    5. 8.5 Thermal Resistance Characteristics for D (SOIC) Package
    6. 8.6 Switching Characteristics
    7. 8.7 Timing Diagrams
  10. 9 Detailed Description
    1. 9.1  Power Supply
    2. 9.2  Oscillator
    3. 9.3  Predrivers
    4. 9.4  Full Bridge
    5. 9.5  RF Amplifier
    6. 9.6  Band-Pass Filter and Limiter
    7. 9.7  Diagnosis
    8. 9.8  Power-on Reset
    9. 9.9  Frequency Divider
    10. 9.10 Digital Demodulator
    11. 9.11 Transponder Resonance-Frequency Measurement
    12. 9.12 SCI Encoder
    13. 9.13 Control Logic
    14. 9.14 Test Pins
  11. 10Applications, Implementation, and Layout
    1. 10.1 Application Diagram
  12. 11Device and Documentation Support
    1. 11.1 Getting Started and Next Steps
    2. 11.2 Device Nomenclature
    3. 11.3 Tools and Software
    4. 11.4 Documentation Support
    5. 11.5 Support Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

9.4 Full Bridge

The full bridge drives the antenna current at the carrier frequency during the charge phase and the active time of the write phase. The minimal load resistance the full bridge sees between its outputs in normal operation at the resonance frequency of the antenna is 43.3 Ω. When the full bridge is not active, the two driver outputs are switched to ground.

Both outputs of the full bridge are protected independently against short circuits to ground.

In case of an occurring short circuit, the full bridge is switched off in less than 10 µs to avoid a drop of the supply voltage. After a delay time of less than 10 ms the full bridge is switched on again to test if the short circuit is still there. An overcurrent due to a resistive short to ground that is higher than the maximum current in normal operation but lower than the current threshold for overcurrent protection does not need to be considered.