SDLS975 April   2024 LSF0002

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
    6. 5.6 Switching Characteristics (Translating Down): BN = 3.3V
    7. 5.7 Switching Characteristics (Translating Down): BN = 2.5V
    8. 5.8 Switching Characteristics (Translating Up): BN = 3.3V
    9. 5.9 Switching Characteristics (Translating Up):BN = 2.5V
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Auto Bidirectional Voltage Translation
      2. 7.3.2 VBIAS/ Enable
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Open-Drain Interface (I2C, PMBus, SMBus, and GPIO)
        1. 8.2.1.1 Design Requirements
          1. 8.2.1.1.1 Enable and Disable Guidelines
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Bidirectional Translation
          2. 8.2.1.2.2 Pull-Up Resistor Sizing
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Mixed-Mode Voltage Translation
      3. 8.2.3 Voltage Translation for Vref_B < Vref_A + 0.8V
    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 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)
  • DTQ|6
Thermal pad, mechanical data (Package|Pins)
Orderable Information
8.2.1.2.2 Pull-Up Resistor Sizing

The pull-up resistor value needs to limit the current through the pass transistor when it is in the ON state to about 15mA. Doing this causes a voltage drop of 260mV to 350mV to have a valid LOW signal on the downstream channel. If the current through the pass transistor is higher than 15mA, then the voltage drop is also higher in the ON state. To set the current through each pass transistor at 15mA, calculate the pull-up resistor value using the following equation:

Equation 1. Rpu = (Vpu - 0.35 V)0.015 A 

Table 8-3 provides resistor values, reference voltages, and currents at 8mA, 5mA, and 3mA. The resistor value shown in the +10% column (or a larger value) should be used so that the voltage drop across the transistor is 350mV or less. The external driver must be able to sink the total current from the resistors on both sides of the LSF family device at 0.175V, although the 15mA applies only to current flowing through the LSF family device. The device driving the low state at 0.175V must sink current from one or more of the pull-up resistors and maintain VOL. A decrease in resistance will increase current, and thus result in increased VOL.

Table 8-3 Pull-Up Resistor Values
VPU(1)(2)8mA5mA3mA
NOMINAL (Ω)+10%(3) (Ω)NOMINAL (Ω)+10%(3) (Ω)NOMINAL (Ω)+10%(3) (Ω)
5V581639930102315501705
3.3V3694065906499831082
2.5V269296430473717788
1.8V181199290319483532
1.5V144158230253383422
1.2V106117170187283312
(1) Calculated for VOL = 0.35V
(2) Assumes output driver VOL = 0.175V at stated current
(3) +10% to compensate for VDD range and resistor tolerance