This paper presents a 427MHz OOK modulated transmitter with energy harvesting for multi-channel neural acquisition. A power efficient OOK modulator is proposed integrated a 3-input AND gate array to drive the power transistors. The requirement on the driving capability of the VCO output is greatly reduced. A 9-stage ring oscillator based VCO is designed with PLL and edge-combining technology. A crystal based 6.78MHz oscillator is combined with the wireless power transmitter coil to power up the entire transmitter design, as well as to generate a reference frequency to the transmitter, resulting a crystal-less transmitter design. The proposed design was fabricated in 180nm technology, occupying a silicon area of only 0.26mm2. Experimental results show a power consumption of 96渭W with a -19dBm output. A 48pJ/bit efficiency is achieved under a data rate of 2Mbps.