| Digital to analog converter, analog integrated filter , bandgap reference and high drive capability operational amplifier are indispensability basic circuit of communication system. Following the recently international attractive research task, we put the important studying problem on design of high frequency . high definition digital to analog converter and high performance analog integrated filter among a practical system of communication, during the research work, we gain a lot of new high performance circuits of digital to analog converter and analog integrated filters with enhancement of high characteristics and realization of new structure circuit, which have been successfully applied in communication integrated circuits, and receives better practical application effect.The significant investigation result of this paper are as follows:In the first chapter, we firstly introduce the basic concept and important electrical characteristics of digital to analog converter and bandgap reference, review the historical progress of electric filters, summarize the methodologies and implementing techniques of filters, and then analyze the practical circuits realization of filters and unrealistic impact factors on performance of filters, finally, we set forth significance of this studying problem and main research work of this paper.In the second chapter, we firstly present a circuit of 8-bit, 80MHz samples/s thermometer-decoded DAC with hierarchical symmetrical switching sequences which will compensate gradient error, on the basis of 8-bit DAC, we then present high frequency, high definition 12-bit, 80MHz samples/s current-steering DAC.In the third chapter, a methodologies to realize second-order band-pass filter with which center frequency tuned in a wide range using MCDI (Multiple output Current-mode Differential Integrator), these two kinds of MCDI are composed of PMOS and NMOS input transistors respectively, lastly we compare these two integrators' merits and disadvantages.In the fourth chapter, a fourth-order Chebyshev low-pass filter employs new low voltage, highly linear, wide inputting range transconductor is proposed, thenwe presents a new circuit to tune gm value of transconductor accurately, which employs a new switched-capacitor circuit to change the bias current of transconductor, a third order elliptical function low-pass filter with accurate tunable frequency has been designed using transconductor that is not only with voltage common-mode negative feedback, but also with varying bias-triode transistors which can improve the linearity of this circuit.In the fifth chapter, a new fully differential operational amplifier with voltage and current-mode negative feedback has been proposed, which can stabilize its quiescent operation point, using the characteristic of MOS transistors which operate in the triode region acting as active variable resistor, a fully differential fourth-order Chebyshev low-pass filter with tunable frequency and Bessel low-pass filter with accurate group delay based on R-MOSFET-C and operational amplifier has been designed.In the sixth chapter, firstly a high accuracy bandgap reference circuit has been presented, which has the characteristic of temperature coefficient much better than that of the same circuit of the world, and then a noval high drive capability CMOS operational amplifier has been proposed, which are all suitable for the application of communication integrated circuit system.In the seventh chapter, some of the above proposed new circuit, such as high frequency , high definition 12-bit, 80MHz samples/s current-steering DAC and fully differential R-MOSFET-C Bessel filter with accurate group delay, high accuracy bandgap reference and high drive capability CMOS operational amplifier have been applied in communication GSM baseband I/O port integrated circuit, all the above blocks meet well with the design requirements of the system, and gain the better testing results, in the mean time, the above proposed high accuracy bandgap reference circuit als...
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