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TPSM828303AEVM-245: Issue during TPSM828303 and TPSM82866A EVM evaluation

Michael Yeo
Intellectual 2420 points
Part Number: TPSM828303AEVM-245
Other Parts Discussed in Thread: TPSM828303, TPSM82866A, , TPSM82866AA0PEVM

Tool/software:

Team,

Korean IP Network Camera customer named as Hanwha Vision is evaluating TPSM828303 and TPSM82866A EVMs. Refer to the below for the EVMs which they are using.

  • TPSM828303AEVM-245
  • TPSM82866AA0PEVM

But, they are seeing efficiency performance gap and issue as below. Please review it and let us know your opinion.

1. TPSM828303 EVM Efficiency

  • Input voltage: 5V
  • Output: 1.8V / 3A
  • Expected efficiency in datasheet: about 90%
  • Measured efficiency: 85.2%

2. TPSM82866A EVM Efficiency

  • Input voltage: 5V
  • Output: 1.2V / 6A
  • Expected efficiency in datasheet: about 86%
  • Measured efficiency: 79.2%

 

3. TPSM82866A EVM output voltage change

  • Input voltage: 5V
  • Output: Configured as 3.3V (R1: 100K, R2: 22K, VSET: LOW)
  • Issue #1: Audible noise happens while increasing output current higher than 3A.
  • Issue #2: High Output voltage drop happens while increasing output current higher than 4A.

Best Regards,

Michael.

  • 0
    TI__Mastermind 22080 points

    Hello Michael,

    thanks for reaching out in E2E.

    For the efficiency gaps, mentioned in 1. and 2. it is important to perform the measurement with the correct setup. When the voltage measurement includes voltage drop of high current traces or connectors, or even the shunt of the current meter, then the measured efficiency result can be lower. Please refer to this application note for more details: "Accurately measuring efficiency of ultralow-IQ devices". Please let me know if this was already considered.

    3. #1: Audible noise can be generated from the capacitors on a PCB. Maybe this aspect was not the first priority during EVM design. Such acoustic noise can be minimized as described in this application note: "How to Reduce Acoustic Noise of MLCCs in Power Applications".

    3. #2: The voltage drop might be again caused by losses across high current paths. The output voltage should be sensed close to the IC (usually at the first capacitor of COUT). The sense terminals (S+ and S- at J5) of the EVM can be used for accurate VOUT measurements. Please let me know if this was already considered.

    Best regards,

    Andreas.