SCPS221G October   2010  – November 2018 TCA9406


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Typical Application Block Diagram for TCA9406
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  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  Timing Requirements (VCCA = 1.8 V ± 0.15 V)
    7. 6.7  Timing Requirements (VCCA = 2.5 V ± 0.2 V)
    8. 6.8  Timing Requirements (VCCA = 3.3 V ± 0.3 V)
    9. 6.9  Switching Characteristics (VCCA = 1.8 V ± 0.15 V)
    10. 6.10 Switching Characteristics (VCCA = 2.5 V ± 0.2 V)
    11. 6.11 Switching Characteristics (VCCA = 3.3 V ± 0.3 V)
    12. 6.12 Typical Characteristics
  7. Parameter Measurement Information
    1. 7.1 Voltage Waveforms
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Architecture
      2. 8.3.2 Input Driver Requirements
      3. 8.3.3 Output Load Considerations
      4. 8.3.4 Enable and Disable
      5. 8.3.5 Pullup Resistors on I/O Lines
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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


The TCA9406 architecture (see ) is an auto-direction-sensing based translator that does not require a direction-control signal to control the direction of data flow from A to B or from B to A.

TCA9406 arch_ces640.gifFigure 10. Architecture of a TCA9406 Cell

These two bidirectional channels independently determine the direction of data flow without a direction-control signal. Each I/O pin is automatically reconfigured as either an input or an output, which is how this auto-direction feature is realized.

The TCA9406 is part of TI's "Switch" type voltage translator family and employs two key circuits to enable this voltage translation:

1) An N-channel pass-gate transistor topology that ties the A-port to the B-port


2) Output one-shot (O.S.) edge-rate accelerator circuitry to detect and accelerate rising edges on the A or B ports

For bidirectional voltage translation, pullup resistors are included on the device for dc current sourcing capability. The VGATE gate bias of the N-channel pass transistor is set at approximately one threshold voltage (VT) above the VCC level of the low-voltage side. Data can flow in either direction without guidance from a control signal.

The O.S. rising-edge rate accelerator circuitry speeds up the output slew rate by monitoring the input edge for transitions, helping maintain the data rate through the device. During a low-to-high signal rising edge, the O.S. circuits turn on the PMOS transistors (T1, T2) to increase the current drive capability of the driver for approximately 30 ns or 95% of the input edge, whichever occurs first. This edge-rate acceleration provides high ac drive by bypassing the internal 10-kΩ pullup resistors during the low-to-high transition to speed up the signal. The output resistance of the driver is decreased to approximately 50 Ω to 70 Ω during this acceleration phase. To minimize dynamic ICC and the possibility of signal contention, the user should wait for the O.S. circuit to turn off before applying a signal in the opposite direction. The worst-case duration is equal to the minimum pulse-width number provided in the Timing Requirements section of this data sheet.