SCDS466A August   2023  – December 2024 TMUX7612

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Thermal Information
    4. 5.4  Source or Drain Current through Switch
    5. 5.5  Recommended Operating Conditions
    6. 5.6  Electrical Characteristics (Global)
    7. 5.7  Electrical Characteristics (±15 V Dual Supply)
    8. 5.8  Switching Characteristics (±15 V Dual Supply)
    9. 5.9  Electrical Characteristics (±20 V Dual Supply)
    10. 5.10 Switching Characteristics (±20 V Dual Supply)
    11. 5.11 Electrical Characteristics (+37.5 V/–12.5 V Dual Supply)
    12. 5.12 Switching Characteristics (+37.5 V/–12.5 V Dual Supply)
    13. 5.13 Electrical Characteristics (12 V Single Supply)
    14. 5.14 Switching Characteristics (12 V Single Supply)
    15. 5.15 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1  On-Resistance
    2. 6.2  Off-Leakage Current
    3. 6.3  On-Leakage Current
    4. 6.4  tON and tOFF Time
    5. 6.5  Propagation Delay
    6. 6.6  Charge Injection
    7. 6.7  Off Isolation
    8. 6.8  Channel-to-Channel Crosstalk
    9. 6.9  Bandwidth
    10. 6.10 THD + Noise
    11. 6.11 Power Supply Rejection Ratio (PSRR)
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Bidirectional Operation
      2. 7.3.2 Rail-to-Rail Operation
      3. 7.3.3 1.8 V Logic Compatible Inputs
      4. 7.3.4 Flat On-Resistance
      5. 7.3.5 Power-Up Sequence Free
      6. 7.3.6 Ultra-Low Charge Injection
      7. 7.3.7 Ultra-Low Leakage Current
    4. 7.4 Device Functional Modes
      1. 7.4.1 Truth Tables
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Detailed Design Procedure
      2. 8.2.2 Design Requirements
      3. 8.2.3 Application Curve
    3. 8.3 Thermal Considerations
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Tape and Reel Information
    2. 11.2 Mechanical Data

Package Options

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

8.3 Thermal Considerations

For analog switches in many applications, several 100s of mA of current needs to be supported through the switch (from source to drain, or NO/NC to COM). Many devices already have a maximum current specified based on ambient temperature, but if a device specifies with junction temperature or you want to calculate for your specific use case (temperature, supply voltage, channels in parallel) you can use the following equations and scheme.

There are mainly 2 limitations to this maximum current:

  1. Inherent metal limitations of the device
  2. Thermal self-heating limitations

To calculate maximum current for your specific setup you need the following information:

  • TA = maximum ambient temperature
  • RϴJA = package thermal coefficients
  • RON = on resistance
  • n = number of channels in parallel
  • Limitations on maximum current based on junction temperature from the datasheet
Below is an example using TMUX7612 specifications:

Device maximum TJ=150°C

For this example we assume 20°C of self-heating at a maximum TA=105°C and operating with 4 channels at once at ±15V. We can assume worst case RON = 2.2Ω. This number is taken from the maximum specified value at TA = 125°C where TJ=125°C since the specification assumes no self-heating. Using the following equation we can calculate the maximum thermal limitation.

Similarly, you can calculate the TJ and total power dissipated in these examples with the following equations. Note there will be some small power dissipated from the supply current consumption of the device, which is ignored here.

Equation 1. T J   =   R θ J A × I 2 × R O N × n + T A
Equation 2. P t o t a l = T J - T A R θ J A

Pulse current can be calculated the same way, but using the duty cycle, d. Typically, pulse current is specified at a 10% duty cycle; however, do not exceed the maximum current provided in the pulse current table even with a shorter duty cycle.

Equation 3. I   =   1 d T J - T A R θ J A × R O N × n
Equation 4. T J = R θ J A × ( d × I ) 2 × R O N × n + T A