Analog-to-digital converter
US5481129A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1995 |
| Grant date | Jan 2, 1996 |
| Priority date | — |
| Expiry date | Feb 21, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M1/365
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.