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Original question:

TPS562209: To know the margin of min Operating junction temperature on TPS562209

TPS562209: TPS562209 switching ferquency

Jeff Xie
Intellectual 1780 points
Part Number: TPS562209

Hi all,

Customer test the SW pin waveform on several boards and found that one board's switching frequency is higher than normal.

The test conditions are Vin:9.3V; Vout:5V load is no load. Customer want to know 790kHz switch frequency is normal or not.

1. 790kHz

2. normal chip

  • 0
    TI__Genius 9550 points

    hi,

    The frequency (791KHZ) is acceptable. 

  • 0 in reply to Jason Wang (BSR-MV)
    TI__Expert 4875 points

    Hi Jeff,

    First of all, it is better to use higher bandwidth like 250MHz or 500MHz to measure SW node. You will get a sharp rising and falling edge which is more close to real world. And use 50% to 50% level to measure the SW frequency. 

    And for TPS562209, it is a DCAP2 part which has a quasi fixed frequency. There is no internal clock for frequency sync and the fixed frequency is got by the on time calculation circuit. Due to the delay and some other factor, this quasi fixed frequency will vary slightly with Vin, Vout and Iout. There are some graphs in datasheet showing it. 791kHz is higher than typical but it could be a reasonable frequency which is close to the max variation.