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Ceramic input capacitor for PTH08080WAH?
I am trying to design a circuit with the PTH08080W module to power a USB device from a 12 v automotive battery. We are not planning on using an output cap and have the 348 ohm resistor installed correctly. The input capacitor we have currently selected is pn RFS-25V331MI6#5 (datasheet can be found here http://www.elna.co.jp/en/capacitor/alumi/catalog/pdf/rfs_e.pdf) which is rated to 25v, 330 uF capacitance, and 675 mArms. We are having issues with getting the module to output a usable voltage. The output pins read .060V and the module draws a steady 100mA with or without any load connected.
Our first impressions is that the module has become damaged somehow and are wondering if we are using an incorrect capacitor and caused this issue. Please advise if this capacitor should suffice for the input to the PTH08080W module. Additionally, we would prefer to use a ceramic capacitor for size considerations, but the datasheet leads us to believe that only an electrolytic or tantalum capacitor will suffice. Please advise if a ceramic input cap can be used if it meets the 100 uF and 650 mArms requirements.
The PTH08080W appears to be non-functional. The power IC has likely been overstressed.
The PTH08080 must not have any external voltage applied to the out pins or bus at any time.
What is the output voltage set to in this application?
This can be caused by :
1. The 12V battery through it long power leads can generate greater than 60V transients . This transient can occur on either ground (-) bounce ot (+)input Power bus.
A transient suppressor on the input bus is recommended to prevent voltage overstress.
2. Is the inhibit pin controlled or open?
Send me an e-mail with you contact information so we can discuss this application ?
My e-mail address is
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