The Design Of Current Mode Linear Super Broad-band Four Quadrant Analog Multiplier

Analog multiplier was the critical module of continuous-time-signal processing circuits,which was widely used in the modulation and demodulation of wireless communication signals,instrumentation,control equipment and some special nonlinear signal processing systems,Especially in the communication systems,with the decline of the system supply voltage,the raise of operating frequency of the circuits and the complex of signal modulation,the analog multiplier circuit for nonlinear processing directly affects the accuracy of the operation of the signal.Therefore,the analog multiplier circuit with low-voltage,wide-band and high-precision played an essential role in the overall performance of the system.The design of a broadband,linear current analog multiplier circuit was introduced in this paper.The basic topology of the circuit was the "quarter squared" multiplier structure,using the complementary metal oxide semiconductor(CMOS)process.The characteristics of the current mode circuit was used to avoid the disadvantages of the traditional Gilbert double balanced multiplier's high operation voltage,to realize the operating at relatively low supply voltage.The differential input structure was distributed which used in the circuit to reduce the load capacitance of the loaded-device and improved the working frequency of the circuit.In addition,Differential input signals in the same circuits was used to achieve the signals addition and subtraction,which avoid the phase deviation in traditional current because of the different signal paths.In the design of the square circuit,a full differential current square circuit with negative feedback was proposed based on the principle of differential circuit and Wilson current source,which used feedback to improve the accuracy of the current operation,and used the differential circuit to offset the error caused by the back-gate effect,and further improved the accuracy of the operation.The design completed from the circuit-level to the layout-level,and finished the circuit's pre-simulation and post-simulation by using the Advanced Design System(ADS)software.According to the simulation results,when the power supply voltage was 3V,the-3dB frequency was greater than 2GHz,the linearity error of the circuit was less than 1%and the total harmonic distortion at 1MHz was less than 2%.Some reference value to the design of the current "quarter-squared" multiplication circuits was had by this paper.