SCDS477A June   2024  – June 2025 TMUX1308A , TMUX1309A

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Thermal Information: TMUX1308A
    4. 6.4  Thermal Information: TMUX1309A
    5. 6.5  Recommended Operating Conditions
    6. 6.6  Electrical Characteristics
    7. 6.7  Logic and Dynamic Characteristics
    8. 6.8  Timing Characteristics
    9. 6.9  Injection Current Coupling
    10. 6.10 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1  On-Resistance
    2. 7.2  Off-Leakage Current
    3. 7.3  On-Leakage Current
    4. 7.4  Transition Time
    5. 7.5  Break-Before-Make
    6. 7.6  tON(EN) and tOFF(EN)
    7. 7.7  Charge Injection
    8. 7.8  Off Isolation
    9. 7.9  Crosstalk
    10. 7.10 Bandwidth
    11. 7.11 Injection Current Control
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Bidirectional Operation
      2. 8.3.2 Rail-to-Rail Operation
      3. 8.3.3 1.8V Logic Compatible Inputs
      4. 8.3.4 Fail-Safe Logic
      5. 8.3.5 High-Impedance Optimization
      6. 8.3.6 Injection Current Control
        1. 8.3.6.1 TMUX13xxA is Powered, Channel is Unselected, and the Input Signal is Greater Than VDD (VDD = 5V, VINPUT = 5.5V)
        2. 8.3.6.2 TMUX13xxA is Powered, Channel is Selected, and the Input Signal is Greater Than VDD (VDD = 5V, VINPUT = 5.5V)
        3. 8.3.6.3 TMUX13xxA is Unpowered and the Input Signal has a Voltage Present (VDD = 0V, VINPUT = 3V)
    4. 8.4 Device Functional Modes
    5. 8.5 Truth Tables
  10. 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 Short To Battery Protection
      4. 9.2.4 Application Curve
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

9.2.3 Short To Battery Protection

When evaluating the safety and reliability of an automotive grade multiplexer, it is important to note their performance under various operating conditions. In the case of TMUX13xxA, we examine its response to various short-to-battery conditions to provide insight on system level design for automotive optimization. It is important to design around short-to-battery as failure to do so can result in operational issues. The following section shows a deep dive into two scenarios to demonstrate the behavior of the TMUX1308A under short-to-battery conditions using a 5V supply voltage.

We begin with the following setup to explore our first scenario with channel S7 selected and channel S0 experiencing a short-to-battery condition.

TMUX1308A TMUX1309A Channel S7 Selected, Channel S0 Experiencing a Short-to-Battery ConditionFigure 9-2 Channel S7 Selected, Channel S0 Experiencing a Short-to-Battery Condition

Table 9-2 indicates values of ∆VOUT, VSBAT and minimum RLIM for various VBAT cases when considering a maximum allotment of 25mAfor IS/ID. Choosing too large of an RLIM will negatively affect ∆VOUT as well as substantially limit current flow. Choosing too small of an RLIM can damage the device.

Table 9-2 RLim Values for 25mA Through the Switch
VBAT RLIM ∆VOUT (typ) VSBAT
12V 470 < 10µV 5.6V
19V 750 < 10µV 5.6V
24V 1K < 10µV 5.6V
36V 1.5K < 10µV 5.6V
48V 2K < 10µV 5.6V
60V 2.4K < 10µV 5.6V
TMUX1308A TMUX1309A All Unselected Channels Experiencing a Short-to-Battery ConditionFigure 9-3 All Unselected Channels Experiencing a Short-to-Battery Condition

We then evaluate the scenario of seeing a short-to-battery condition on all unselected channels at the same time. The follwing table indicates values when considering a maximum allotment of 12.5mA for IS/ID(for more information, see Section 6.1). If you have the potential to see short-to-battery on all channels at the same time, then 12.5mA is the limiting factor. Here again choosing too large of an RLIM will negatively affect ∆VOUT as well as substantially limit current flow.

CAUTION: To avoid damage to the device do not choose too small of an RLIM.
Table 9-3 RLim Values for 12.5mA Through the Switch

VBAT

RLIM

∆VOUT (typ)

VSBAT

12V

1K

< 10µV

5.6V

19V

1.5K

< 10µV

5.6V

24V

2K

< 10µV

5.6V

36V

3K

< 10µV

5.6V

48V

3.9K

< 10µV

5.6V

60V

4.7K

< 10µV

5.6V

TMUX1308A TMUX1309A Short-to-Battery Condition Only on a Single Selected ChannelFigure 9-4 Short-to-Battery Condition Only on a Single Selected Channel
CAUTION: To avoid damage to the device do not choose too small of an RLIM.

In conclusion, several short-to-battery case studies were observed using a 5V supply. Note that if using a lower supply voltage, the RLim values will change for optimal current flow. It is important to protect against short-to-battery conditions as a failure to do so can result in system level issues. Take care to design around these conditions and the electrical characteristics for proper device operation.