This paper investigates power amplifiers (PAs) for micro-nuclear magnetic resonance (NMR) applications, focusing on class-D and class-E topologies. Class-D is initially explored, offering advantages in integration due to its reduced component count. While class-E is known to surpass class-D in efficiency, it conventionally requires a significant number of passive components. To address this, an approach where the NMR coil itself is integrated as part of the class-E PA is proposed, eliminating the need for a separate matching network and resonator inductance. Both amplifier topologies were designed and simulated, delivering 450 mW of output power. Class-E demonstrated better efficiency, reaching approximately 66% compared to class-D’s 53% within the 21.3-63.9 MHz Larmour frequency range, corresponding to an external magnetic field of 0.5−1.5T suitable for micro-NMR. Additionally, a duty cycle controller was incorporated to enable flexible output power control for NMR experiments. This design allows class-E to achieve compactness comparable to class-D while maintaining its higher efficiency, making it a promising solution for micro-NMR applications.