Hi, TI expert.
A customer company constructed a circuit using the LM73606-Q1, and I have a few questions regarding it.
-INPUT: 5V, OUTPUT 4V
(Questions)
1. Fsw: Use 500KHz (Is Fsw suitable?)
2. Is the power inductor applied to the circuit suitable?
3. Is the Input CAP / Output CAP applied to the circuit suitable?
4. Are there any other parts to be added or modified?
Please confirm and reply.
Please tell us if you have any further questions. Thank you.
Hi,
1) Yes the 500kHz frequency is ok.
2) Yes the power inductor is ok
3) Yes the input capacitor is suitable. The output capacitor is also suitable
4) I double check that with 6V input you should be able to do 5V output at 6A. Check figure 60 on datasheet below
Thanks
-Arief
Hi, Arief
Thanks for the answer.
I have additional questions.
The power inductor said OK,
If you calculate with the inductor calculation formula of the Datasheet,
It is about 0.9uH~2.7uH.
(Questions)
1. As mentioned above, please double check that there is no problem even if you apply 4.7uH.
2. If you look at the Datasheet, there is a content related to adding Bulk-Cap to the VIN pin. Is it necessary?
If applied, is there an appropriate capacity value?
100uF or lower capacity possible?
Hi Grady,
No problem. I think the value of 4.7uH should be ok.
The evaluation module uses 6.8uH
The reason why you got the value of inductor to be small is because of the VIN and VOUT value for your design is quite close to each other. If you put VIN to be at 8V then the inductor value will get larger. So it depends on what is your nominal VIN.
The EVM design should work down to 6V.
One benefit that i could see if you are using 2.7uH or lower is a lower DCR therefore it improves efficiency.
The bulk capacitor is there just in case there is a long cable from the VIN power supply that may create inductance and spikes on the VIN if you hot plug the wire.
The purpose of that bulk capacitor is for ESR damping of the LC ringing due to a long cable. The value lower than 100uF should be ok.
Thanks
-Arief
