Design of Current steering DAC using 250nm CMOS Technology

To build a digital to analog converter, that only receives digital signal that can only receives digital signal and produces only analog signal. A converter in which digital input signals are changed to essentially proportional analog signals. Abbreviated DAC a device for converting information in the forms of combination of discrete(usually binary) states or signal to information in the form of combinations of discrete(usually binary) states or signal to information in the form of value or magnitude of some characteristics of signal, in relation to standard or reference signal. Digital-toanalog (D/A) converters (sometimes called DACs) are used to present the results of digital computation, storage, or transmission, typically for graphical display or for the control of devices that operate with continuously varying quantities. D/A converter circuits are also used in the design of analog-to-digital converters that employ feedback techniques, such as successive-approximation and counter-comparator types. In such applications, the D/A converter may not necessarily appear as a separately identifiable entity. The fundamental circuit of most D/A converters involves a voltage or current reference; a resistive “ladder network” that derives weighted currents or voltages, usually as discrete fractions of the reference; and a set of switches, operated by the digital input, that determines which currents or voltages will be summed to constitute the output. The output of the D/A converter is proportional to the product of the digital input value and the reference. In many applications, the reference is fixed, and the output bears a fixed proportion to the digital input. In other applications, the reference, as well as the digital input, can vary; a D/A converter that is used in these applications is thus called a multiplying D/A converter. It is principally used for imparting a digitally controlled scale factor, or “gain,” to an analog input signal applied at the reference terminal. Analog to digital converter performs the reverse operation. It has many era of operations in audio and Video form and whiffletree electromagnetic device uses DAC linkage in typewriter. It describes the 3.3 volt, 65 MHz 8 bit CMOS digital to analog converter, includes two stage current cell matrix. This paper describes a 1v CMOS 8 bit DAC with two stage current cell matrix architecture which consists of 4 MSB and 4 LSB current matrix stage. The symmetric two stage current cell matrix architecture allows the designed DAC to reduce not only the complexity of decoding logic, but also the no of high swing current mirrors. The designed DAC with a by 90 nm nwell CMOS standard process. The experiment is based on settling time, Integrity, or non linearity. The designed DAC is fully operational for power supply down to 1 volt such that DAC is suitable for low voltage and low power applications. Keywords— current cell matrix, DAC, high swing cascade current mirror, low power, current steering DAC.