This brief presents a 3-channel single-ended three-level pulse amplitude modulation (PAM-3) transmitter (TX) for high-density multi-channel systems. The proposed TX employs a crosstalk cancellation (XTC) technique for multi-level signaling, which utilizes the information of transitions obtained through the PAM-3 encoding. Combining with a feedforward equalizer (FFE), the proposed XTC technique is implemented by a minimal hardware overhead. Fabricated in 28-nm CMOS technology, a prototype 3-channel TX is tested with channels which insertion loss and signal-to-crosstalk ratio are 7.8 dB and 5.7 dB, respectively. The proposed TX achieves a data rate of 12 Gb/s/ch with a significant XT-induced jitter (CIJ) reduction of 0.432 UI. Furthermore, it provides an energy efficiency of 1.26 pJ/b while occupying an active area of 0.007 mm2 per channel.