The analysis of the structure of adding current-steering to extend D AC-bits is presented, of which the main shortcoming is the decline of the static parameters. The structures of the resistor-type voltage-divider and the capacitor-type voltage-divider are given out, which can extend the bits of DAC by trading off area, power-consumption or speed without influence the static parameters. With the IB MO. 18 ixn CMOS technology, the two structures are simulated, analyzed and verified by Spectre. The result matches the theoretical derivation.%分析了电流舵型数模转换器(DAC)通过增加一路电流以扩展位结构,其最大弊端是降低了原DAC的静态误差参数.并以此提出了电阻分压扩展结构与电容分压扩展结构.这两种结构能在不影响原DAC静态误差参数的情况下以面积与功耗或者速度的代价扩展DAC的位数,提高其精度.基于IBM0.18μmCMOS工艺模型,在Spectre下对两种结构进行仿真验证,结果与理论推导相符.
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