I am using an OPA551 running on +/-15V supplies, connected as a unity gain non-inverting amp. With a 1kHz signal, the output is clipping at about +/-14V with 100k load (as expected), but at only +/- 8.3V into a 33 ohm load (250mA peak). When I apply a 10 ohm load, it clips at about +/- 6.5V (I would expect it to current limit with this load).
Is this expected behavior? Does the output stage run out of headroom at 15V?
The Vout datasheet specs are all at +/-30V supply, so I'm not sure of performance at +/-15V, other than the Isc vs. Vs graph in the datasheet seems to indicate it should not be entering current limit with a 33 ohm load until about 12V peak.
Thanks!