OK, so I dropped models for the 4281/4302 into the design. The thing oscillates like a swine and I'm having real trouble stabilising it. So far i've tried:
* RC between rails and base of small-signal device in VAS cascode
* RC from VAS-VBE junctions to ground
* small compensation caps on the predrivers
Some of this has helped, but I can't 100% stop the amp oscillating (particularly noticeable when you feed it a 1KHz square wave)
Anyone got any ideas to recommend ?
* RC between rails and base of small-signal device in VAS cascode
* RC from VAS-VBE junctions to ground
* small compensation caps on the predrivers
Some of this has helped, but I can't 100% stop the amp oscillating (particularly noticeable when you feed it a 1KHz square wave)
Anyone got any ideas to recommend ?