NATIONAL Semiconductor, represented by Arrow Electronics , has released a dual-CMOS analogue to digital converter. Applications include digital oscilloscopes, automated test equipment (ATE), base stations, satellites and communications systems requiring direct I/Q down-conversion.
The ADC08D1000 digitises two input signals to eight-bit resolution at sampling rates up to 1Gsps while consuming 1.6W from a 1.9V nominal supply. By using the dual-edge sampling feature, the product can achieve 2Gsps sampling from one channel by interleaving the two on-chip converters. Both coarse and fine timing adjustments are available, allowing the sampling clock for each channel to be calibrated independently in 0.1ps increments. A three-wire serial bus controls these adjustments, as well as on-chip functionality and independent gain and offset fine-tuning for I and Q channels. The low power requirements of the ADC08D1000 enable designers to eliminate fans or heat sinks, saving board space and reducing system cost.
The chip has a folding/interpolating architecture. Folding reduces the number of comparators and interpolation reduces the number of front-end amplifiers required, saving power and reducing the load on the input signal. The ADC08D1000 has an ideal pulse response and guarantees no missing codes over the full operating temperature range of -40 to 85°C. It has a low voltage differential signaling interface, which enables reliable transmission of high-speed signals while maintaining low noise and distortion levels.
The ADC08D1000 has a bit-error rate of 10-18. At a 1GHz sampling rate the ADC08D1000 achieves 0.25 least significant bits differential non-linearity and 0.35 least significant bits integral non-linearity, while maintaining 7.5 effective number of bits from dc up to input frequencies of 500MHz. Measured crosstalk between the I and Q channels is less than -77dB. The dual on-chip sample-and-hold amplifiers deliver excellent dynamic performance over a 1.7GHz full-power bandwidth.