Converter breaks 1000 MSPS speed barrier

Analog Devices has launched what it claims is the industry’s first 14-bit DAC to clock at a sample rate of 1.2 giga-samples-per-second.

Analog Devices has launched what it claims is the industry’s first 14-bit digital-to-analog converter (DAC) to clock at a sample rate of 1.2 GSPS (giga-samples-per-second).

The AD9736 operates from 1.8-V and 3.3-V supplies, consuming 380 mW at 1.2 GSPS with the interpolation filter bypassed, and 550 mW with the interpolation filter enabled.

It provides a fast low-voltage differential signalling (LVDS) input interface using a double-data-rate (DDR) mode, which enables high conversion rates over a wide bandwidth. This allows it to receive data at a high speed, while maintaining low distortion and noise, simplifying the transmit signal chain and enabling high quality synthesis of wideband signals at intermediate frequencies up to the Nyquist rate (one half of DAC sampling rate).

The output currents of the AD9736 can be programmed over a range of 10 mA to 30 mA, and can be easily configured for various single-ended or differential circuit topologies. The device’s IMD is 74 dBc at an output frequency of 255 MHz and better than 65 dBc up to a 600 MHz output frequency. SFDR is 63 dBc at a 300 MHz output frequency and 53 dBc at 600 MHz, sampling at 1.2 GSPS. Noise performance is excellent, with noise spectral density of -158 dBm/Hz synthesising a 300-MHz output.

The AD9736 is joined by pin-compatible 12-bit (AD9735) and 10-bit (AD9734) versions. Operating at 1.2 GSPS, these devices feature a 2X digital interpolation filter, which doubles the incoming sample rate from DSPs, ASICs or FPGAs. A novel clock-to-data synchronisation scheme simplifies the interface timing and enables the extreme sample rate to be realised.

The 14-bit AD9736 is sampling now. The device is offered in a 160-pin BGA (ball grid array) package to reduce parasitics and improve performance.

Production quantities for the AD9736, AD9735, and AD9734 will be available at the end of 2004. In 1,000-piece quantities, the AD9736 is priced at $34.95, the pin-compatible 12-bit AD9735 is $19.95, and the 10-bit AD9734 is $14.95.