An acoustic wave filter includes a substrate and a piezoelectric layer over the substrate. First acoustic wave resonators are disposed over the piezoelectric layer and arranged in series along a first branch, and second acoustic wave resonators are disposed over the piezoelectric layer, arranged in parallel, and connected to the first branch and to ground. The first and second acoustic wave resonators include an interdigital transducer electrode interposed between a pair of reflectors. A layer of positive temperature coefficient of frequency dielectric material is disposed over one or more of the first plurality of acoustic wave resonators to control the temperature coefficient of frequency and improve temperature stability of the acoustic wave filter.