Hi,
I followed the typical application of the datasheet of LM2776 and made a chip for get the inverted voltage. However, firstly when I connect the +3.3 V input, the out put is -1 V. After that, when I re-connected the input with +3.3 V, the output shows about 200 mV (close to 0). Then I checked every part of my chip. The pin 2 and 5 are shorted. that means one side of the capacitor is grounded.
From figure 19 of datasheet, I think this is because S2 is closed. But I cannot do anything to fix it. Could you please tell me how to do for get the right output(-3.3 V)when my input is(+3.3V)?
My capacitor are: 1uF and 2.2uF surface mount ceramic capacitor(X7R)
the attachment is my layout.
Looking forward to your answer,
Best,
Jichao Fan
