SCDS402B June   2019  – February 2024 TMUX1136

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 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics (VDD = 5V ±10 %)
    6. 5.6 Electrical Characteristics (VDD = 3.3V ±10 %)
    7. 5.7 Electrical Characteristics (VDD = 1.8V ±10 %)
    8. 5.8 Electrical Characteristics (VDD = 1.2V ±10 %)
    9.     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 Transition Time
    5. 6.5 Break-Before-Make
    6. 6.6 Charge Injection
    7. 6.7 Off Isolation
    8. 6.8 Crosstalk
    9. 6.9 Bandwidth
  8. 7 Detailed Description
    1. 7.1 Functional Block Diagram
    2. 7.2 Feature Description
      1. 7.2.1 Bidirectional Operation
      2. 7.2.2 Rail to Rail Operation
      3. 7.2.3 1.8V Logic Compatible Inputs
      4. 7.2.4 Fail-Safe Logic
      5. 7.2.5 Ultra-low Leakage Current
      6. 7.2.6 Ultra-low Charge Injection
    3. 7.3 Device Functional Modes
      1. 7.3.1 Truth Tables
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 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

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DGS|10
  • DQA|10
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2 Detailed Design Procedure

The TMUX1136 can operate without any external components except for the supply decoupling capacitors. All inputs passing through the switch must fall within the recommend operating conditions of the TMUX1136, including signal range and continuous current. For this design with a supply of 5V the signal range can be 0V to 5V, and the max continuous current can be 30mA.

Photodiodes commonly have a current output that ranges from a few hundred picoamps to tens of microamps based on the amount of light being absorbed. Difference feedback networks can be switched into a transimpedance amplifier in order to scale the output voltage to maximize system dynamic range. Typical feedback resistance is in the 10s-100s of kilo-ohms range where the on resistance of a switch would have minimal impact on system accuracy. However, some applications will have larger photodiode currents due to light exposure and can require a feedback resistor as low as 100Ω. Analog switches and multiplexers commonly have a tradeoff between on-resistance and leakage current, which will both lead to overall system error. Figure 8-1 shows how to configure a multi-channel analog switch to eliminate the impact from on-resistance and select a device optimized for low leakage currents. The drawback of this architecture is that the output impedance of the TIA stage is now the on-resistance of the multiplexer since the second channel is outside the feedback loop. This is commonly an acceptable tradeoff as the on-resistance of the TMUX1136 is very low, 2Ω typical.

The TMUX1136 has a typical On-leakage current of less than 10pA which would lead to an accuracy well within 1% of a full scale 10µA signal. The low ON and OFF capacitance of the TMUX1136 improves system stability by minimizing the total capacitance on the output of the amplifier. Lower capacitance leads to less overshoot and ringing in the system which can cause the amplifier circuit to go unstable if the phase margin is not at least 45°. Refer to Improve Stability Issues with Low CON Multiplexers for more information on calculating the phase margin vs. percent overshoot..