Dc/Dc Converter do not started. Vdd = 5 V. Viso is connected to 1 KOhm. Other pins don't connected.
Can you say me a reason?
Anton: Would you please send me a schematic that shows the ADuM6132 connections and the supply voltages and bypass capacitors? Please note the ADuM6132 datasheet table 11 describes the operation of the undervoltage lockout funtionality and the need for a VDDL = 5V supply voltage in addition to the VDD in order for VISO to operate.
Thank you for your fast response.
The test connection is drawing (PDF) but I have only 12,7V and 14mA at the output.
Do you have any suggestions for me?
From your message, it appears your circuit is now working, but you are expecting more output current and perhaps voltage from the ADuM6132 VISO output. Your schematic shows a 1k load resistor, which is 12.7mA at your 12.7V output stated, my question is are you adding more load to the VISO than the 1k resistor and if so what happens to the output voltage? Also, what is the input voltage at pin 1 VDD when you load VISO? The input current on VDD of the ADuM6132 can be over 300mA when Viso is at max load, and if your VDD 5V supply drops, the Viso can droop and will not be able to supply max output current. Note, the ADuM6132 DC/DC converter uses an air core transformer with a switching frequency of about 120MHz, which produces a small isolated DC/DC, but with a very low efficiency and about 1W of power dissipation, requiring layout considerations described in the datasheet which include multiple GND vias in a pad connected to a ground plane.
It works but on the surface i have mesured 80 C, too dangerous for my application.
Anton: In my previous posting on this discussion, I described how the ADuM6132 can consume up to 1W of power and will need multiple GND vias connected directly to a large GND plane to help dissipate this power. The theta JA junction to ambient thermal resistance per datasheet table 2 is 45C/W, which for 1W dissipation means 45C rise, which at 25C ambient would be 70C junction. Your layout may be able to be improved to reduce the 80C surface temp you measure, by adding multiple GND Vias connected directly to a large GND plane, as described in the PCB Layout section of the datasheet. It is not possible to apply a heat sink to an isolated device, so these layout techniques are needed to reduce the device temperature.
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