High Speed Analog to Digital Converter Using SiGe Technology

Period of Performance: 09/29/1998 - 12/30/2000


Phase 2 SBIR

Recipient Firm

Sierra Monolithics, Inc.
103 W. Torrance Blvd., Suite 102
Redondo Beach, CA 90277
Principal Investigator

Research Topics


Commercial A/D Converters on silicon or GaAs do not simultaneously provide GHz sampling rates and high 16-bit resolution. In order to satisfy both of these performance criteria for a 100 MHz input signal bandwidth, the device technology has to be fast enough to reduce the sampling aperture jitter down to less than 50 fsec and the digitizing error to 15 uV. SMI proposes an A/D Converter approach that will meet these requirements. The approach uses IBM's SiGe HBT technology for low jitter (5 fsec), high sample rate (4 GSPS) and a unique Delta-Sigma architecture for the digitizing accuracy. The novel Delta-Sigma architecture uses a hybrid second order noise-shaping loop, dynamic element matching of improved DAC accuracy, and linearity enhanced substraction circuits with an embedded DAC to achieve 16-bit resolution. System design and device simulations for the A/D were performed in Phase I. The Phase II effort will include the design, fabrication , and testing of the Modulator.