I am trying to incorporate a Buck-Boost DC-DC converter into my design using the LTC3534 and I cannot seem to get it working.
Below I will post images of the datasheet recommended design, my implementation and also my PCB design files (top and bottom layer) although it is pretty hard to read.
Testing the implemented design:
- Input voltage = 4V;
- Maximum current = 0.1A;
- No load.
The result is that the device wants to draw as much current as it can (I have tested it up to 400mA and it is the same). The voltage supply drops to 2.3V because of the current limiting, the output goes to 1.33V. The feedback pin is at 0.4V. (which seems logical as (R1 / R1 + R2)*1.33V = 0.4V, but it should be 1V at an output of 3.3V).
Important things to note: PWM pin is directly hooked to Vin, R6 shorted and C22 removed.
I have prior tested the board without the output capacitor C22 mounted on the board. (I forgot to solder it) Could have this damaged the IC?
Lastly, is it possible that my inductor is saturating, as it is rated at 2.4A@100kHz and the circuit operates at 1MHz (In my opinion this does not matter as I used no load so the current through it is a minimum)? This is the inductor used.
I have also tried another board with no current limiting and it drew a lot of current until one of the pins connected to the inductor became shorted to ground and the IC became toast.