SLVT216 July   2024 TPS546C25 , TPS546E25

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2General
    1. 2.1 No Immediate Disable From Soft Start
    2. 2.2 Power Stage Over Temperature Protect
    3. 2.3 Negative Current Limit
    4. 2.4 Programmable Reference DAC gain low
  6. 3Security
    1. 3.1 Standard Write Protection Does Not Work on Secondary Device
    2. 3.2 Device Does Not NACK Incorrect Passkey Per PMBus 1.5
    3. 3.3 Device Does Not Alternate Between Lock and Unlock When Passkey is Written Multiple Times
  7. 4Stacking Interface and Operation of P2_PLUS_Commands
    1. 4.1 Inconsistent P2_PLUS_(various) NACKing by Secondary Device
    2. 4.2 IOUT_OC_FAULT_LIMIT Not Readable on Secondary Device Via P2_PLUS_READ
    3. 4.3 STACK_CONFIG Writable When Should be Read Only
    4. 4.4 Secondary Device ACK's Write to Some Read-Only Registers
    5. 4.5 Secondary Device NACKs All P2_PLUS_WRITE Commands With PHASE = 0xFF
    6. 4.6 Secondary Asserts IVD for P2_PLUS_READ of ALERT_MASK_(various) With PHASE = 0xFF
    7. 4.7 Secondary Device NACKing P2_PLUS_(various) With Valid PHASE
    8. 4.8 Invalid PAGE is ACKed for P2_PLUS_READ Command
  8. 5PMBUS
    1. 5.1 READ_IOUT Data Format is Not Correct
    2. 5.2 OPERATION Not changing VOUT_SOURCE When OFF = b’1
    3. 5.3 PIN_DETECT_OVERRIDE Power-On Source Control Inverted
    4. 5.4 PIN_DETECT_OVERRIDE Bit 15 OVRD_STACK is Not Working Correctly
    5. 5.5 STATUS_OTHER FRST_2_ALRT Does Not Assert STATUS_BYTE or STATUS_WORD Other Bit 0
    6. 5.6 Clamping VOUT by VREF Range Not setting VOUT_MAX_MIN in STATUS_VOUT
  9. 6Summary
  10. 7References

4.1 Inconsistent P2_PLUS_(various) NACKing by Secondary Device

  • Description: Some P2_PLUS commands that can be allowed are NACKed on secondary devices, but not all the time.
  • System Impact: An incorrect fault response is signaled from these PS-PLUS commands, such as IOUT_CAL_OFFSET and OT_FAULT_RESPONSE. Other Commands include MFR_REVISION with P2_PLUS_WRITE, PINSTRAP_RESULT_OVR with P2_PLUS_WRITE, FUSION_ID1 with P2_PLUS_READ, ALERT_MASK_BYTE with P2_PLUS_WRITE.
  • Workaround or Mitigation: Use the unique address for the secondary device instead of P2_PLUS for the specified commands, or ignore faults when using P2_PLUS commands to the specified commands on secondary devices.
  • Disposition: Design fix planned for final silicon.