Tool/software:
Hello，
The schematic diagram of SN6501 is shown below. When the load is unloaded, the customer tests that the TP9 voltage is 4.3V. Under a 100 ohm resistor load, the TP9 voltage will drop to 4.1V. The LDO TPS76933 outputs 3.3V, which does not meet the LDO's VIN=VOUT+1V specification. Is there any application risk in this situation? How much current does an increase in load lead to LDO output not reaching 3.3V? Do you need to adjust the output of the transformer?
Thanks！
Hi Jeno,
Thank you for reaching out.
From the output voltage plot provided in SN6501 datasheet (see screenshot below), the 4.3V at no load and 4.1V at 33mA load seem to be expected values. If the LDO needs an input that should be 1V higher than the output voltage or LDO has a drop-out voltage (VDO) of >1V, then the final output might not stay stable at 3.3V across loads. As the load current increase, the output at TP9 decreases and this could result in a decrease at LDO output.
We recommend customer to choose an LDO that has a drop-out voltage of <300mV to make sure the output is well regulated. For best LDO selection, I recommend you to post this question on power management forum. Thanks.
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum
Regards,
Koteshwar Rao
