Microelectronic assemblies, related devices and methods, are disclosed herein. In some embodiments, a microelectronic assembly may include a package substrate having a surface; a die having a first surface and an opposing second surface; and a chiplet having a first surface and an opposing second surface, wherein the chiplet is between the surface of the package substrate and the first surface of the die, wherein the first surface of the chiplet is coupled to the surface of the package substrate and the second surface of the chiplet is coupled to the first surface of the die, and wherein the chiplet includes: a capacitor at the first surface; and an element at the second surface, wherein the element includes a switching transistor or a diode.