In this paper, we present a fully integrated transceiver ASIC for low field NMR spectroscopy. The chip integrates a conventional low intermediate frequency (low-IF) receiver together with a high-voltage (HV) H-bridge power amplifier (PA) and a PLL frequency synthesizer. The receiver consists of a low noise amplifier (LNA), a quadrature down conversion mixer and a baseband amplifier. It achieves a measured input referred voltage noise density of 1.1 nV/sqrt(Hz). The integrated PLL frequency synthesizer supports operating Larmor frequencies of benchtop and portable NMR. The on-chip PA can drive up to 1.4 A_pp into a 1 ohm resistor and 1.6 A_ppinto a 3 mm, parallel-tuned NMR coil. When operating with a 3 mm NMR coil inside a 1.45 T unshimmed NMR magnet, the system achieves a spin sensitivity of 9.2*10^(15) spins/sqrt(Hz) and a concentration sensitivity of 1.79 mM.