Another ADP2108 at +/- 1V

Question

Hi all, 
 
 First of all: hobbyist here, first time using one of these switchers. I've not followed the recommended layout and possibly made some other mistakes. 
 However... 
 
 I am using an ADP2108AUJZ-3.3-R7 in a design that will be powered of a Li-ion battery (or USB/external power through a MAX1555). 
 
 The switcher outputs the desired 3.3V as long as I cut the traces to the load and only have the (recommended) 10uF cap at the output. If I add another 10uF on top of the one that is recommended, the output goes to 0.98V at startup. 
 Most of it (as well as some troubleshooting I've done with the help of others at StackExchange) is described here: https://electronics.stackexchange.com/questions/469178/buck-converter-drops-only-keeps-vout-if-no-traces-are-connected/471081 
 
 I've read some of the other threads and tried to modify the input to the enable line as follows: resistor from Vin to enable line, with cap and bleed resistor to GND to make the enable line go high long after Vin has gone high and stabilized. Changed values up until the enable line goes high 300ms after Vin. Also added additional cap on the Vin (tried 10/20/47uF and 10nF). Still I get 0.98v on the output. Tried adding a 100R resistor on the load side to GND to get some loading. 
 I found that every once in a while I end up with 3.3V. If that happens and I power off and back on, it's back to 0.98V. Have not managed to find a way to reproduce. Tried to make sure Vin/Vout/EN are all at 0V before reapplying power, with no luck. 
 At this moment I managed to break of the enable pin so cannot try and experiment any further so figured it might be time to ask for help here while I wait for a replacement. 
 
 This is a hobby project and I already spent way more time then I would like. The obvious solution would be replace the ic with an LDO and get it over with. However, I wouldn't learn anything that way. 
 Is there anything else I could try before I give up? I might do a second board design following the recommended board layout, but I'm not sure I can make time for that. 
 
 Regards, 
 
 Dieter 
 ON4DD

EZAutoReply · Accepted Answer

Hi Dieter, 
 I'm the applications engineer for this part and I want to know more about your circuit. 
 would you be able to send your full schematic/layout including the circuit the ADP2108 is powering. 
 what load current do you expect from the circuit the ADP2108 is powering - you can try supplying the load circuit with a 3.3V power supply and measure the current during start-up and normal operation. - it will give us some clue if the ADP2108 hits current limit during start up thus preventing to ramp up to its final output voltage. 
 do you have some scopeshots during the startup that we can have a look? 
 Also, do you have ADP2108 evaluation board to try powering your load? 
 Apologies for the delayed response, I just get back to office from the holidays. 
 Thank you very much for your interest in using ADI parts. 
 regards, 
 Jefferson)

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Another ADP2108 at +/- 1V