Dear All,
Our device is implemented with LPC 4370.
There is a question about the case where our device is not powered on and voltage is supplied from the target host side via the USB cable.
[Background]
(1) Our device is a USB device, not a host.
(2) Our device is "self-powered device", not "bus-powered device".
(3) The other USB host device and our device are connected by a USB cable, and a voltage within the specified range is supplied to the USB cable from the USB Host device.
[conditions]
(1) The device power supply is OFF, and the following pins of LPC4370 are not powered.
VDD (IO)
VDD (REG) (3 V 3)
VDDA (3 V 3)
USB0_VDDA3V_DRIVER
USB 0 _ VDDA 3 V 3
Vprog (pf)
(2)Voltage is applied to our device from the other host's side via the USB cable under the above conditions.
[Question]
Is there a problem in applying a voltage within the specified range to the following USB pins of LPC 4370?
In other words, will internal latch-up and malfunctions not occur?
Pin name / specified range
USB0_VBUS / min 0[V], max 3.6[V]
USB0_DP / min 0[V], max 3.6[V]
USB0_DM / min 0[V], max 3.6[V]
USB0_ID / min 0[V], max 3.6[V]
Best Regards,
Yasushi
Solved! Go to Solution.
Hi,
The data sheet provides absolute max rates for a scenario similar to yours (Vddio=0v) as it is specified in table 10.
so you shouldn't have issues if you are careful with voltage spikes when restoring the supply to the device.
Have a great day,
Sol
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Hi,
The data sheet provides absolute max rates for a scenario similar to yours (Vddio=0v) as it is specified in table 10.
so you shouldn't have issues if you are careful with voltage spikes when restoring the supply to the device.
Have a great day,
Sol
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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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Dear Soledad,
Thank you for your support.
I satisfy with your answer and advice.
Best Regards,
Yasushi Hasegawa