Radiation-Hardened, Analog-to-Digital Converter with High-Bit Precision

ABSTRACT: Ridgetop Group will design a radiation-hardened, high speed (2 GS/S) analog-to-digital converter (ADC) with high-bit precision for use in low bit error rate (BER) Quadrature Amplitude Modulation (QAM) demodulator applications. Due to its high linearity and dynamic range, the ADC block can be incorporated into critical communications systems where radiation exposure would otherwise cause degradation of performance. Ridgetop will employ an innovative time-interleaved pipeline ADC approach, based on the most advanced silicon-germanium (SiGe) BiCMOS technology available, providing more than 2 bits higher effective number of bits (ENOB = 11.0 bits) than the best commercially available radiation-tolerant 2 GS/s ADCs (ENOB = 8.9 bits). In addition, the ADC consumes 70% less power than the commercial ADCs, conserving valuable spacecraft power. Due to the inherent radiation tolerance of the SiGe heterojunction bipolar transistors (HBT) and 130 nm thin-oxide CMOS transistors (in combination with radiation-hardening-by-design, (RHBD) techniques) the ADC will be tolerant to 1 Mrad of total ionizing dose (TID) radiation. The ADC will be also sufficiently hardened against single-event effects (SEL) of 120 Mev-cm2/mg, making it an ideal building block for advanced space-based communication systems. BENEFIT: Precision data converters are critical to the performance of high speed Digital Processing (DSP) Systems. The sampling rate and resolution of the converters define the performance aspects of the entire system. With the aggressive performance improvements of 2 GS/S sampling rate, high Effective Number of Bits (ENOB), and low power, this ADC overcomes a significant barrier to higher performance communications systems. Ridgetop"s innovative time-interleaved SiGe-based ADC will improve the resolution, linearity, power consumption and radiation hardness of state-of-the art of ADCs used in advanced communication systems. As a modular, self-contained building block based on a popular, Trusted Foundry process, the ADC will be an important library element for future system designs. The high-performance ADC finds wide applicability in satellite communication systems, space-based radar applications, medical imaging devices, software defined radio applications, power amplifier linearization, high speed data acquisition applications, high speed test and instrumentation equipment.