To provide a small driver IC, in a pass transistor logic circuit that converts k-bit digital signals into analog signals, transistors supplied with a first-bit signal are arranged in a line in the channel width direction. The channel width of transistors supplied with second to kth-bit signals is made larger than (e.g., preferably larger than two times and smaller than eight times) that of the transistors supplied with the first-bit signal. The transistors are preferably arranged such that transistors of the same conductivity type are located adjacent to each other wherever possible.