A digital-to-analog converter (DAC) is a function that converts digital data into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. Unlike analog signals, digital data can be transmitted, manipulated, and stored without degradation, albeit with more complex equipment. But a DAC is needed to convert the digital signal to analog to drive an earphone or loudspeaker amplifier in order to produce sound. This project presents a 3.5 GS/s 6-bit current-steering digital-to-analog converter (DAC) with auxiliary circuitry to assist testing in a 1 V digital 28-nm CMOS process. The DAC uses only thin-oxide transistors and occupies 0.035 mm2, making it suitable to embedding in VLSI systems. Design for Test stands for IC design techniques that add certain testability features to a hardware product design. The premise of the added features is that they make it easier to develop and apply manufacturing tests for the designed hardware. The purpose of manufacturing tests is to validate that the product hardware contains no MANUFACTURING defects that could, otherwise, adversely affect the product’s correct functioning. Tests are applied at several steps in the hardware manufacturing flow and, for certain products, may also be used for hardware maintenance in the customer’s environment