Can LNK306 be used with minimum input voltage 16V DC?

Can anybody answer my question, tks.

Hi Wang Arthur,
Thank you for your interest of using Power Integrations' part.
Unfortunately LNK306 is designed for high voltage applications. The minimum drain voltage that it can work is 50V but 70V is our recommended minimum voltage that it can work without any problem. Below the minimum voltage, the required drain current wouldn't be met so it is not possible for your desired specification.

Hi Mallora,
Firstly, thank you for your reply. We have established an evaluation board to check whether LNK306 can be used with low voltage input (16V DC, 24V DC, 32V DC) and with 8V DC output. We find that LNK306 output was actually 8V DC with ripple 80mV which is as same as we expected before. So we think your IC can meet our requirement. But you said below the minimum voltage, the required drain current wouldn't be met. Can you kindly give me specific cause. I am sure you have tested LNK306 with low voltage input, or LNK306’s datasheet would not say the minimum voltage input is 70V DC. What happened to LNK306 when it operated with low voltage input. You know we must give our manager the specific failure mode about LNK306 with low voltage input. Actually we have used LNK306 with 16V DC to 115V DC input and 8V DC output for our new product design. And we are testing our product now. So it is a little more emergency. If it can not work well with low voltage input. We must choose another IC from your company at once. Thank you very much.

Hi Wang Arthur,

Can you share your schematic so I can better understand your implementation.
What I initially thinking is problem with start-up with drain current providing supply to the controller to start but since you have DC input, it can directly provide supply to your BP pin but needs some regulator with your wide input DC range. If this is the case, it will work even with your input specification.

Hi, Mallora
We test LNK306GN with light load. We probe voltage on Pin S as the green wave shown. We find that when the internal mosfet turns on, the voltage on Pin S firstly goes up to the input voltage, then it goes down with a down slope. In the period when the internal mosfet turns on, the down slope voltage is about 3V. It is not related with input voltage. With 20V DC input the drop voltage is 3V. With 80V DC input, the drop voltage is still 3V. Moreover, with light load, some time in a circle the voltage on Pin S does not equal to the input voltage and does not equal to the ground voltage but it does equal to the output voltage. I don't notice this wave from the datasheet. And the frequency of the voltage on Pin S is about only 8kHz. I don't know the reason. Does that mean IC operates in an unstable state. But the output voltage is still right. Here is my schematic and the voltage wave on PIN S. Thank you.

Hi, Mallora
Are you there?

Hi Arthur,

Since you had a good start-up and your waveform is switching good, you are good to go. Just have full qualification based on your application if it is passing all your requirements. Thank you.