Hello TI support,
Can you please help me with the LM3481? I still have not solved an isue I have using the Sut down pin.
The stepup used is to boost 12Volt to 24 Volts. All works well. But when I connect the SD pin to 5 Volts, it will not shut down. what happens is that the output Voltages drops from 24 Volts to 11Volts. in the datasheet it is stated that it will go into sleepmode and draws only a few uA.
I use a 68k normally to gnd. I have put in series with the 68k resistor a 10k to plus 5Volt. when I connect this 78K to plus 5 Volt, it lowers to 11Volts.
when I connect the junction 10k-|-68k to the gnd, it delivers 24Volts again.
I also connected the pin directly( via 10k) to 5Volts, but the outcome is the same( 11Volts)
I can share the schematics and pcb layout if needed. but the schematic is standard and derived from Webench.
kind regards,
Rob van VReden