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TPS54J061: TPS54J061 selection

Daviel Almonte
Intellectual 2635 points
Part Number: TPS54J061
Other Parts Discussed in Thread: TPS543620EVM, TPS543620

For the TPS54J061 to generate from 12Vin the following voltages:

  • 0.95V or 1.03V (~2A or more) +/-30mV tolerance
  • 1.8V (~3.5A or more) +/- 90mV tolerance
  • Others such as 1.2V, which is not as stringent in requirement

 

These two rails has the requirement of low noise with line and load regulation of <0.4% and <1.2% respectively.

the transient response of this part is Ideal.  However, considering the switch on time (t_on) at 95ns max especially that we have 12V as input, do you think it is a suitable candidate for these rails?

  • 0
    TI__Mastermind 35115 points

    Hi Daviel,

    The TPS54J061 can work for this. Even though the maximum 95 ns minimum on-time suggests the 600 kHz setting has to be used, the 1100kHz setting is also ok. With constant on-time all that hitting the minimum on-time does is cause the fsw to drop due to the on-time being limited. If the fsw starts getting limited by the minimum on-time of 95 ns, the fsw would just drop to ~830 kHz. (0.95V/12V*1/95ns = 830kHz)

    If something with better control over the fsw is needed so that the noise is more predictable, the TPS543620 can work. This uses fixed frequency control so it has an oscillator which sets the fsw. The TPS543620 transient response can be slightly slower than the TPS54J061 because it uses fixed frequency control. However the high fsw the TPS543620 is capable with its very low minimum on-time allows for very high loop bandwidth allowing it to have almost the same transient response. The TPS543620EVM is designed for 12V to 1V conversion so it can provide a good reference for what type of performance can be expected. Both circuits on the EVM keep the 1V output within +/-30 mV with a 3-A step.

    Let me know if you have any further questions.

    Anthony