LMR16030: design support

hi, Hailiang,

Yes, LMR16030 could use for 60V 3A application ,here is a SCH and PCB you could use for reference. 

Elena

Hi Elena,

Since I still haven't received the sample of the EVM, could you pls help find an EVM and demo for customers? Thanks.

Regards,

Hailiang

hi, Hailiang,

have you request EVM online ? The shipping process is already recover these days, please kindly wait. If you have got tracking number, you can monitor on it.

Elena

Hi Elena,

Yes, I request one via ti store. But the EVM have not left Shanghai yet.

Regards,

Hailiang

Hi Elena,

There are some problem when I demo the LMR16030EVM. Could you pls help?

1. When I test the SW Pin, I found that the frequency was quite different from the frequency I set.
When I choose a 10.9k resistor, the measured switching frequency is about 70kHz, not the calculated value 1000kHz.

2. Also, when the divider resistors are 150k and 10k, the output voltage is 10.5V instead of the calculated value of 12V.

Iout=0.5A, Set Vout=12V(CH1),

Regards,

Hailiang

hi Hailiang, 

Please next time do not reply to a closed ticket, it's hard for us to tracking and get lost. You could rise up a new one for better support.

The frequency is drop during light load or drop out , could you comment your input voltage and loading, and this is test based on TI EVM right ?

Elena

Hi Elena,

Ok. I see.

This test is based on the EVM board. As mentioned, the output voltage is set to 12V, but it is actually 10.5V. Iout=0.5A, it should be in PWM mode. The input voltage is 28V as shown in the figure.

Any suggestion?

Thanks and best regards.

Hailiang

hi, Hailiang,

Have you change the inductor , is it 6.8uH ?, is the EVM work on default 5V before you change to 12V, ? 

Elena

Hi Elena，

Yes, I change the inductor to 10μF, with larger Isat and Irsm, XAL7050-103. And the original output of the EVM board is 5V.

Regards,

Hailiang

hi, Hailiang,

looking from the EVM SCH, the Cout is 16V , so please add another 22uf 25V cap on Vout for 12V application and try to check with higher loading, Iload=500mA the device is work in PFM mode, the waveform looks right.

Elena

Hi Elena，

Considering the Cout is small and piezoelectric effect, I have added a 25V/56µF electrolytic capacitance . Also, I added 80V/33µF Cin to stabilize the input voltage.

I'll test under heavier loads later. 

Regards，

Hailiang