Abstract: The invention is a circuit and method for selecting a plurality of different types of resisters and for reliably manufacturing a current generator across different wafer lots. In one embodiment, a monolithic current generator applies the output voltage of a voltage reference circuit across a plurality of series-connected resisters of different types. The resisters are preferably statistically independent resisters, which permits a total resistance with a predefined standard resistance deviation across manufacturing wafer lots. An output current may then be produced which has a predefined standard current deviation across manufacturing wafer lots. In a preferred embodiment, no more than six different types of resisters are used. The resisters may be chosen from the group consisting of diffused resisters, implanted resisters, thin film resisters, metal resisters, and composite resisters. The present invention also includes a method for reliably producing current generators across wafer lots.

Abstract: An A-to-D converter 300 has a comparator 126 with a number of comparator cells 902. Each comparator cell 902 includes a current mirror 1700 that reduces kickback noise. Current mirror 1700 includes a bipolar current mirror 1705 and an NMOS current mirror 1709. The bipolar current mirror 1705 provides an ac ground paralleling NMOS transistor 1704 in the NMOS current mirror 1709 to reduce kickback noise.

Abstract: A two-step analog-to-digital converter and BiCMOS fabrication method. The fabrication method provides pseudosubstrate isolation of digital CMOS devices from the analog devices. The converter uses NPN current switching in a flash analog-to-digital converter and in a digital-to-analog converter for low noise operation. CMOS digital error correction and BiCMOS output drivers provide high packing density plus large output load handling. Timing control aggregates switching events and puts them into intervals when noise sensitive operations are inactive. The fabrication method uses a thin epitaxial layer with limited thermal processing to provide NPN and PNP devices with large breakdown and Early voltages. Laser trimmed resistors provide small long term drift due to dopant stabilization in underlying BPSG and low hydrogen nitride passivation.

Abstract: Analog to digital conversion begins by terminating the acquisition phase of the analog input signal and immediately starting the successive approximation conversion phase upon receipt of a start conversion command. Upon the completion of the successive approximation conversion phase and latching the result, the array is rest if required. The comparator offset is sampled-and-held, if required, and the acquisition phase is initiated and continues until the receipt or occurrence of the next start conversion command.

Abstract: Aperture delay and jitter are reduced when the sequence of operation of a charge redistribution analog to digital converter is arranged so that signal acquisition occurs in the idle time of the converter. Conversion begins by terminating the acquisition or sample phase immediately upon receipt of the start conversion command. Approximation begins directly thereafter. Upon completion of the successive approximation conversion phase and latching the result the capacitor array is discharged. The comparator offset is sampled and held and the acquisition phase is initiated and continues until receipt or occurrence of the next start conversion command.