SDLS973 june   2023 LSF0101

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 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  LSF0101 AC Performance (Translating Down) Switching Characteristics , VCCB = 3.3 V
    7. 6.7  LSF0101 AC Performance (Translating Down) Switching Characteristics, VCCB = 2.5 V
    8. 6.8  LSF0101 AC Performance (Translating Up) Switching Characteristics, VCCB = 3.3 V
    9. 6.9  LSF0101 AC Performance (Translating Up) Switching Characteristics, VCCB = 2.5 V
    10. 6.10 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Auto Bidirectional Voltage Translation
      2. 8.3.2 Output Enable
    4. 8.4 Device Functional Modes
      1. 8.4.1 Up and Down Translation
        1. 8.4.1.1 Up Translation
        2. 8.4.1.2 Down Translation
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Open-Drain Interface (I2C, PMBus, SMBus, and GPIO)
        1. 9.2.1.1 Design Requirements
          1. 9.2.1.1.1 Enable, Disable, and Reference Voltage Guidelines
          2. 9.2.1.1.2 Bias Circuitry
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Bidirectional Translation
          2. 9.2.1.2.2 Pull-Up Resistor Sizing
          3. 9.2.1.2.3 Single Supply Translation
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Voltage Translation for Vref_B < Vref_A + 0.8 V
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.4.1.1 Up Translation

When the signal is being driven from A to B and the An port is HIGH, the switch will be OFF and the Bn port will then be driven to a voltage higher than Vref_A by the pull-up resistor that is connected to the pull-up supply voltage (VPU). This functionality allows seamless translation between higher and lower voltages selected by the user, without the need for directional control. Pull-up resistors are always required on the high side, and pull-ups are only required on the low side, if the low side of the device's output is open drain or its input has a leakage greater than 1 µA.

GUID-20230222-SS0I-CJRC-P0QF-BRGDRLCDVR35-low.svgFigure 8-2 Up Translation Example Schematic with Push-Pull and Open Drain Configuration

Up translation with the LSF requires attention to two important factors: maximum data rate and sink current. Maximum data rate is directly related to the rising edge of the output signal. Sink current depends on supply values and the chosen pull-up resistor values. Equation 1 shows the maximum data rate formula and Equation 2 shows the maximum sink current formula, both of which are estimations. A low RC value is needed to reach high speeds, which also require strong drivers. Please see the Up Translation with the LSF Family video for estimated data rate and sink current calculations based on circuit components.

Equation 1. 13×2RB1CB1= 16RB1CB1 (bitssecond)
Equation 2. IOL ≅ VCCARA1+ VCCBRB1 (A)