SLVSGG6B april   2022  – june 2023 TPS25981

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
      1.      16
    8. 7.8 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Undervoltage Lockout (UVLO and UVP)
      2. 8.3.2 Overvoltage Lockout (OVLO)
      3. 8.3.3 Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 8.3.3.1 Slew Rate (dVdt) and Inrush Current Control
        2. 8.3.3.2 Circuit-Breaker During Steady-State
        3. 8.3.3.3 Active Current Limiting During Start-Up
        4. 8.3.3.4 Short-Circuit Protection
      4. 8.3.4 Analog Load Current Monitor
      5. 8.3.5 Overtemperature Protection (OTP)
      6. 8.3.6 Fault Response and Indication (FLT)
      7. 8.3.7 Power Good Indication (PG)
      8. 8.3.8 Quick Output Discharge (QOD)
      9. 8.3.9 Reverse Current Blocking FET Driver
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Single Device, Self-Controlled
      2. 9.1.2 Parallel Operation
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Device Selection
        2. 9.2.2.2 Setting Output Voltage Rise Time (tR)
        3. 9.2.2.3 Setting Overcurrent Threshold (ILIM)
        4. 9.2.2.4 Setting Overcurrent Blanking Interval (tITIMER)
        5. 9.2.2.5 Voltage Drop
      3. 9.2.3 Application Curves
  11. 10Power Supply Recommendations
    1. 10.1 Transient Protection
    2. 10.2 Output Short-Circuit Measurements
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  13. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 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

9.2 Typical Application

TPS259814x can be used for optical module power rail protection. Optical modules are commonly used in high-bandwidth data communication systems such as optical networking equipment, enterprise/data-center switches and routers. Several variants of optical modules are available in the market, which differ in the form-factor and the data speed support (Gbit/s). Of these, the popular variant double dense quad small form-factor pluggable (QSFP-DD) module supports speeds up to 400 Gbit/s. In addition to the system protection during hot-plug events, the other key requirement for optical module is the tight voltage regulation. The optical module uses 3.3-V supply and requires voltage regulation within ±5% for proper operation.

A typical power tree of such system is shown in Figure 9-7. The optical line card consists of DC-DC converter, protection device (eFuse) and power supply filters. The DC-DC converter steps-down the 12 V to 3.3 V and maintains the 3.3-V rail within ±2 %. The power supply filtering network uses ‘LC’ components to reduce high frequency noise injection into the optical module. The DC resistance of the inductor ‘L’ causes voltage drop of around 1.5% which leaves us with a voltage drop budget of just 1.5% (3.3 V × 1.5% = 50 mV) across the protection device. Considering a maximum load current of 5.5 A per module, the maximum ON-resistance of the protection device must be less than 9 mΩ. TPS259814x eFuse offers a very low ON-resistance of 6 mΩ (typical), thereby meeting the target specification with additional margin to spare and simplifying the overall system design.

GUID-20220314-SS0I-NKXT-2LQW-7MTTGQ7SBLPS-low.svg Figure 9-7 Power Tree Block Diagram of a Typical Optical Line Card
As shown in Figure 9-7, ModPrsL signal acts as a handshake signal between the line card and the optical module. ModPrsL is always pulled to ground inside the module. When the module is hot-plugged into the host “Optical Line Card” connector, the ModPrsL signal pulls down the OVLO pin and enables the TPS259814x eFuse to power the module. This action ensures that power is applied on the port only when a module is plugged in and disconnected when there is no module present.

GUID-20220319-SS0I-PQZV-DNHT-THV5NW2B5B6V-low.gif

* Optional circuit components needed for transient protection depending on input and output inductance. Please refer to Transient Protection section for details.

Figure 9-8 Optical Module Port Protection