| 摘要 |
<p>A MOS (preferably CMOS type) analog NOR amplifier suitable for use in building a programmable array logic (PAL) or the like, or for other uses. The analog NOR amplifier consists of a reference MOS transistor (1) and a first pull-up device (4) at one branch and a plurality of input MOS transistors (2I ... 2N) and a second pull-up device (5) at another branch with a constant current source (3) connected to the source terminals of these MOS transistors, which forms a configuration similar to a differential amplifier. With the gate terminals of the plurality of input MOS transistors (2I ... 2N) as logic input ends, the drain terminals of the same will act as the output end of a standard NOR gate and the drain terminal of the reference MOS transistor (1) will behave as the output end of a standard OR gate. On account of the differential amplifier structure, the MOS analog NOR amplifier will not generate current spikes when in logic transient transition and the amplifier gain can be kept low thereby acquiring a low output impedance to further improve the logic transient response. Furthermore, a constant current source (3) is provided to be utilised in the MOS analog NOR amplifier, whereby the Miller capacitance of the amplifier will be maintained at almost zero so that a high speed but cost effective NOR gate is achievable.</p> |
