Are AC4490-200 and AC4490-1000 pin to pin compatible?

Yes, however the VCC voltages are different. The VCC pin 10/11 differences are as below: -1000 pin 10: 3.3 - 5.5V, +/- 50mV ripple pin 11: 3.3V +/- 3%, +/- 100mV ripple -200 pin 10: 3.3 - 5.5V, +/- 50mV ripple (internally connected to pin 11) pin 11: 3.3 - 5.5V, +/- 50mV (internally connected to pin 10)