SLVSDR6C June   2017  – March 2018 TPS25740B

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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
    8. 7.8 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
      1. 8.1.1 VBUS Capacitance
      2. 8.1.2 USB Data Communications
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  ENSRC
      2. 8.3.2  USB Type-C CC Logic (CC1, CC2)
      3. 8.3.3  USB PD BMC Transmission (CC1, CC2, VTX)
      4. 8.3.4  USB PD BMC Reception (CC1, CC2)
      5. 8.3.5  Discharging (DSCG, VPWR)
        1. 8.3.5.1 Discharging after a Fault (VPWR)
      6. 8.3.6  Configuring Voltage Capabilities (HIPWR)
      7. 8.3.7  Configuring Power Capabilities (PSEL, PCTRL, HIPWR)
      8. 8.3.8  Gate Driver (GDNG, GDNS)
      9. 8.3.9  Fault Monitoring and Protection
        1. 8.3.9.1 Over/Under Voltage (VBUS)
        2. 8.3.9.2 Over-Current Protection (ISNS, VBUS)
        3. 8.3.9.3 System Fault Input (GD, VPWR)
      10. 8.3.10 Voltage Control (CTL1, CTL2,CTL3)
      11. 8.3.11 Sink Attachment Indicator (DVDD)
      12. 8.3.12 Power Supplies (VAUX, VDD, VPWR, DVDD)
      13. 8.3.13 Grounds (AGND, GND)
      14. 8.3.14 Output Power Supply (DVDD)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Sleep Mode
      2. 8.4.2 Checking VBUS at Start Up
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 System-Level ESD Protection
      2. 9.1.2 Using ENSRC to Enable the Power Supply upon Sink Attachment
      3. 9.1.3 Use of GD Internal Clamp
      4. 9.1.4 Resistor Divider on GD for Programmable Start Up
      5. 9.1.5 Selection of the CTL1, CTL2, and CTL3 Resistors (R(FBL1), R(FBL2), and R(FBL3))
      6. 9.1.6 Voltage Transition Requirements
      7. 9.1.7 VBUS Slew Control using GDNG C(SLEW)
      8. 9.1.8 Tuning OCP using RF and CF
    2. 9.2 Typical Applications
      1. 9.2.1 Typical Application, A/C Power Source (Wall Adapter)
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Power Pin Bypass Capacitors
          2. 9.2.1.2.2 Non-Configurable Components
          3. 9.2.1.2.3 Configurable Components
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Typical Application, D/C Power Source
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Power Pin Bypass Capacitors
          2. 9.2.2.2.2 Non-Configurable Components
          3. 9.2.2.2.3 Configurable Components
        3. 9.2.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 D/C Power Source (Power Hub)
      2. 9.3.2 A/C Power Source (Wall Adapter)
      3. 9.3.3 Dual-Port A/C Power Source (Wall Adaptor)
      4. 9.3.4 D/C Power Source (Power Hub with 3.3 V Rail)
  10. 10Power Supply Recommendations
    1. 10.1 VDD
    2. 10.2 VPWR
  11. 11Layout
    1. 11.1 Port Current Kelvin Sensing
    2. 11.2 Layout Guidelines
      1. 11.2.1 Power Pin Bypass Capacitors
      2. 11.2.2 Supporting Components
    3. 11.3 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

8.3.3 USB PD BMC Transmission (CC1, CC2, VTX)

An example of the BMC signal, specifically the end of the preamble and beginning of start-of-packet (SOP) is shown below. There is always an edge at the end of each bit or unit interval, and ones have an edge half way through the unit interval.

TPS25740B BMC_Encoded_End.gifFigure 24. BMC Encoded End of Preamble, Beginning of SOP

While engaging in USB PD communications, the device is applying I(RP1.5) or I(RP3.0), so the CC line has a DC voltage of 0.918 V or 1.68 V, respectively. When the BMC signal is transmitted on the CC line, the transmitter overrides this DC voltage as shown in Figure 25. The transmitter bias rail (VTX) is internally generated and may not be used for any other purpose in the system. The VTX pin is only high while the TPS25740B is transmitting a USB PD message.

TPS25740B USB_PD_BMC.gifFigure 25. USB PD BMC Transmission on the CC Line

The device transmissions meet the eye diagram USB PD requirements (refer to USB PD in Documentation Support) across the recommended temperature range. Figure 26 shows the transmitter schematic.

TPS25740B USB_PD_BMC_transmitter.gifFigure 26. USB PD BMC Transmitter Schematic

The transmit eye diagram shown in Figure 28 was measured using the test load shown in Figure 27 with a CLOAD within the allowed range. The total capacitance CLOAD is computed as:

Equation 1. CLOAD = C(RX) + CCablePlug x 2 + Ca + CReceiver

Where:

  • 200 pF < C(RX)< 600 pF
  • CCablePlug< 25 pF
  • Ca < 625 pF
  • 200 pF < CReceiver< 600 pF

Therefore, 400 pF < CLOAD< 1850 pF.

TPS25740B Test_Load_BMC.gifFigure 27. Test Load for BMC Transmitter

Figure 28 shows the transmit eye diagram for the TPS25740B.

TPS25740B transmit_eye_diagram_slbsdg8.pngFigure 28. Transmit Eye Diagram (BMC)