Analog Devices introduced a 24-bit sigma-delta analog-to-digital converter (ADC) with the industry's lowest power consumption and leading-edge accuracy. Consuming only 65 microamps, this new analog front-end outperforms its closest competitor with 25 percent lower power dissipation and six times the resolution. Available in a tiny MSOP-10 package and at a competitive price, it also includes an on-chip buffer and an internal clock generator, making this the most integrated sigma-delta ADC on the market. Sigma-delta ADCs are ideal for portable instrumentation; sensor, temperature, and pressure measurement; and weigh scale applications.
New Ultra Low-Power Sigma-Delta ADCs
The new 24-bit sigma-delta ADC, the AD7791, also comes in a 16-bit version, the AD7790. Both accept differential inputs, which can be buffered or unbuffered; output data rates are software programmable. Parts without the buffer, and with a fixed 16.6 Hz data rate, are also available in 16- and 24-bit versions (AD7788 & AD7789). All parts are low-power analog front-ends for low frequency measurement applications. Each consumes 65 microamps when operated with a 3 V supply and 75 microamps when operated with a 5 V supply (buffer disabled).
Featuring rms noise of only 1.5 microvolts, the AD7791 operates from an internally generated clock, eliminating the need for a user-supplied clock source. Its output data rate is software programmable, allowing rates up to 120 Hz. At the default conversion rate of 16.6 Hz, the AD7791 provides simultaneous 50 Hz and 60 Hz rejection. The p-p resolution from the part varies with the programmed output data rate. The device operates from a single 3 V or 5 V power supply, and supply voltage monitoring is included. It can be used in single or continuous conversion mode.
Pricing and Availability
The new sigma-delta ADCs come in 10-lead MSOP packaging and are priced as follows in 1,000-piece quantities: 24-bit AD7791 - $3.83; 16-bit AD7790 - $2.95; 24-bit AD7789 - $2.95; 16-bit AD7788 - $1.99. Samples and evaluation boards are available now.
