SLVSDD7A September   2016  – February 2019 UCD9090A


  1. Features
  2. Applications
  3. Description
    1.     Typical Application Schematic
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
  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 I2C/Smbus/PMBus Timing Requirements
    7. 6.7 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 TI Fusion GUI
      2. 7.3.2 PMBus Interface
      3. 7.3.3 Rail Configuration
    4. 7.4 Device Functional Modes
      1. 7.4.1  Power Supply Sequencing
        1. Turn-On Sequencing
        2. Turn-Off Sequencing
        3. Sequencing Configuration Options
      2. 7.4.2  Pin-Selected Rail States
      3. 7.4.3  Monitoring
        1. Voltage Monitoring
        2. Current Monitoring
        3. Remote Temperature Monitoring and Internal Temperature Sensor
        4. Temperature by Host Input
      4. 7.4.4  Fault Responses and Alert Processing
      5. 7.4.5  Shut Down All Rails and Sequence On (Resequence)
      6. 7.4.6  GPIOs
      7. 7.4.7  GPO Control
      8. 7.4.8  GPO Dependencies
        1. GPO Delays
        2. State Machine Mode Enable
      9. 7.4.9  GPI Special Functions
        1. Fault Shutdown Rails
        2. Configured as Sequencing Debug Pin
        3. Configured as Fault Pin
        4. Cold Boot Mode Enable
      10. 7.4.10 Power Supply Enables
      11. 7.4.11 Cascading Multiple Devices
      12. 7.4.12 PWM Outputs
        1. FPWM1-8
        2. PWM1-2
      13. 7.4.13 Programmable Multiphase PWMs
      14. 7.4.14 Margining
        1. Open-Loop Margining
        2. Closed-Loop Margining
      15. 7.4.15 Run Time Clock
      16. 7.4.16 System Reset Signal
      17. 7.4.17 Watch Dog Timer
      18. 7.4.18 Data and Error Logging to Flash Memory
      19. 7.4.19 Brownout Function
      20. 7.4.20 PMBus Address Selection
      21. 7.4.21 Device Reset
      22. 7.4.22 JTAG Interface
      23. 7.4.23 Internal Fault Management and Memory Error Correction (ECC)
    5. 7.5 Programming
      1. 7.5.1 Full Configuration Update While in Normal Mode
  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
        1. Estimating ADC Reporting Accuracy
      3. 8.2.3 Application Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RGZ|48
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Rail Configuration

A rail includes voltage, a power supply enable and a margining output. At least one must be included in a rail definition. Once the user has defined how the power supply rails should operate in a particular system, analog input pins and GPIOs can be selected to monitor and enable each supply (Figure 6).

UCD9090A FusionPinAssign_UCD9090.pngFigure 6. Fusion GUI Pin-Assignment Tab

After the pins have been configured, other key monitoring and sequencing criteria are selected for each rail from the VOUT Config tab (Figure 7):

  • Nominal operating voltage (VOUT)
  • Undervoltage (UV) and overvoltage (OV) warning and fault limits
  • Margin-low and margin-high values
  • Power-good on and power-good off limits
  • PMBus or pin-based sequencing control (On/Off Config)
  • Rails, GPOs, and GPIs for Sequence On dependencies
  • Rails, GPOs, and GPIs for Sequence Off dependencies
  • Turn-on and turn-off delay timing
  • Maximum time allowed for a rail to reach POWER_GOOD_ON or POWER_GOOD_OFF after being enabled or disabled
  • Other rails to turn off in case of a fault on a rail (fault-shutdown slaves)
UCD9090A FusionVoutConfig_slvsdd7.pngFigure 7. Fusion GUI VOUT-Config Tab

The Synchronize margins/limits/PG to Vout checkbox is an easy way to change the nominal operating voltage of a rail and also update all of the other limits associated with that rail according to the percentages shown to the right of each entry.

The plot in the upper left section of Figure 7 shows a simulation of the overall sequence-on and sequence-off configuration, including the nominal voltage, the turnon and turnoff delay times, the power-good on and power-good off voltages and any timing dependencies between the rails.

After a rail voltage has reached its POWER_GOOD_ON voltage and is considered to be in regulation, it is compared against two UV and two OV thresholds in order to determine if a warning or fault limit has been exceeded. If a fault is detected, the UCD9090A responds based on a variety of flexible, user-configured options. Faults can cause rails to restart, shut down immediately, sequence off using turnoff delay times or shut down a group of rails and sequence them back on. Different types of faults can result in different responses.

Fault responses, along with a number of other parameters including user-specific manufacturing information and external scaling and offset values, are selected in the different tabs within the Configure function of the Fusion GUI. Once the configuration satisfies the user requirements, it can be written to device SRAM if Fusion GUI is connected to a UCD9090A using an I2C/PMBus. SRAM contents can then be stored to data flash memory so that the configuration remains in the device after a reset or power cycle.

The Fusion GUI Monitor page has a number of options, including a device dashboard and a system dashboard, for viewing and controlling device and system status.

UCD9090A FusionMonPage_RailSystemDB_slvsdd7.pngFigure 8. Fusion GUI Monitor Page

The UCD9090A also has rail state for each rail to debug the system.

Table 1. Rail State

IDLE 1 On condition is not met, or
rail is shut down due to fault, or
rail is waiting for the resequence
SEQ_ON 2 Wait the dependency to be met to assert ENABLE signal
RAMP_UP 4 Enable is asserted and rail is on the way to reach power good threshold. If the power good threshold is set to 0 V, the rail stays at this state even if the monitored voltage is bigger than 0 V.
REGULATION 5 Once the monitoring voltage is over POWER_GOOD when enable signal is asserted, rails stay at this state even if the voltage is below POWER_GOOD late as long as there is no fault action taken.
SEQ_OFF 6 Wait the dependency to be met to de-assert ENABLE signal
STOP_DELAY 7 TOFF_DELAY to de-assert ENABLE signal
RAMP_DOWN 8 Enable signal is de-asserted and rail is ramping down. This state is only available if TOFF_MAX_WARN_LIMIT is not set to unlimited; or If the turn off is triggered by a fault action, rail must not be under fault retry to show RAMP DOWN state. Otherwise, IDLE state is present.

The UCD9090A also has status registers for each rail and the capability to log faults to flash memory for use in system troubleshooting. This is helpful in the event of a power supply or system failure. The status registers (Figure 9) and the fault log (Figure 10) are available in the Fusion GUI. See the UCD90xxx Sequencer and System Health Controller PMBus Command Reference (SLVU352) and the PMBus Specification for detailed descriptions of each status register and supported PMBus commands.

UCD9090A FusionRailStatus_UCD9090.pngFigure 9. Fusion GUI Rail-Status Register
UCD9090A FusionLoggedFaults_slvsdd7.pngFigure 10. Fusion GUI Flash-Error Log (Logged Faults)