ADCs boost sampling rates, hold line on SFDR
Analog Devices today introduced two new ADCs (analog-to-digital converters), which suit wireless-infrastructure applications and test, industrial, and instrumentation applications, respectively.
The AD9445, Analog says, is the first 14-bit, 125-M samples/sec ADC to achieve SFDR (spurious-free dynamic range) of 80 dBc and SNR (signal-to-noise ratio) of 72.5 dBfs at input frequencies up to 300 MHz. The devices will enable designers of wireless-infrastructure equipment to improve cellular base-station receivers through a lower overall system noise at higher intermediate frequencies, resulting in expanded cellular coverage and fewer dropped calls, according to the company.
"[With the AD9445] we increased the sample rate to 125 MSPS and the SFDR was maintained so that higher frequencies could be used and still achieve 90-dBc SFDR," said Jon Hall, strategic marketing manager for Analog's high-speed converter group. "This allows a simplified radio architecture while still achieving very good signal capture performance. This translates into an overall lower cost radio architecture."
The AD9445 also allows a simplified receive path thanks to the higher input frequency, Hall said. "A lot of the interface standards are a multiple of a symbol rate or transfer rates of power," he said. "The more oversampling you get, frees up the digital filtering and the fast sample rate simplifies digital-filter requirements and the front end due to fewer conversion steps."
The company claims that the second new device, the AD9446, is the first 16-bit ADC with 80dB SNR to sample at 100M samples/sec—more than 10´ faster than currently available 16-bit ADCs. The converter also provides 90-dBc SFDR. An available 80M-samples/sec variant reaches 85-dBc SFDR and improves SNR to 82 dBfs.
The AD9446 suits applications in test equipment, real-time signal analysis systems for manufacturing-test processes, and high-end communications and radar equipment.
Both devices are sampling now and will go into full production in September. The converters range from $49.30 to $79.90 (1000).