While the mechanisms are not yet completely understood, ultrasound-based neuromodulation has been emerging as a noninvasive modality for interfacing to both the central and peripheral nervous systems, due to its high penetration depth and good spatial resolution. Commercially available ultrasound transducers for neuromodulation applications are typically single-element focused transducers with a bulky form factor and off-the-shelf electronics for drive. Changing the focal position requires mechanical movement of the transducer itself. High-density ultrasound phased arrays allow for electronic focusing. Here, we present a CMOS 2D beamformer with integrated lead zirconate titanate (PZT) ultrasound transducers for neuromodulation of the peripheral nerves. The proposed prototype can achieve a maximum focal pressure of approximately 100 kPa with a 5 V supply at 0.5 cm depth without including an acoustic matching layer.