Linear and nonlinear channel distortion could degrade the performance of short reach optical interconnection system based on four-level pulse amplitude modulation (PAM4). Using PAM4 transmitter integrated circuits to pre-compensate the signal can alleviate the impact of channel distortion. This paper studies the architecture of PAM4 transmitter chip suitable for short reach optical interconnection. The architecture is based on look-up table (LUT) equalizer and source series terminated digital-to-analog converter, which can flexibly compensate the optical channel distortion. The pipelined multiplexer is used for high speed LUT reading. Digital-to-analog converter pre-driver circuit with feedback resistance is used to decrease the inter-symbol-interference. The post simulation results show that the PAM4 transmitter integrated circuits based on 55 nm process is able to reach 40 Gbit/s. It also enables reconfigurability of various types of equalizers and meets the requirements of next generation data center, access and other optical interconnection networks.