TPS548B22: switch frequency selection for TPS548B22

Hi Oliver,
When you say, "external adjusting", are you referring to DCAP mode setting? This part can be configured to DCAP or DCAP3 via MODE pin resistor setting (page 19 on the data sheet).
In DCAP3 mode, the internal RAMP setting will need to be configured via FSEL pin strap resistor (page 17) based on the recommended RAMP selection table you've provided. Table 7 is just a recommendation based on optimal transient response, jitter performance, and stability. However, the customer may adjust the RAMP value as they wish. The lower the time constant (R÷2), the better the jitters performance, and the worse the transient response. For the higher time constant (Rx3), the worse the jitters performance, and the better the transient response. Please keep in mind that high jitters does not constitute instability. The main effect is the overall amplitude of the output voltage ripple whether the VOUT ripple meets the specification or not.
Thank you .
Amnat

Hi Amnat,
The output is not fixed, customer would change the feedback for margin high and margin low.
So, the real output is between 0.8~1V

Thanks.
Oliver Ou

Hi Oliver,

The frequency selection is entirely up to the customer preference.  Some customer may choose certain frequency prevent any potential interference with other devices. You also have to keep in mind of the minimum on-time and minimum off-time limitation of the our device.  You can use the design tool for this device to properly design the system to stay within our device limitations.  I will send the design tool directly to you.

Thanks.

Amnat

Hi Amnat,

Thanks a lot for your reminder.