Texas Instruments Incorporated announced a highly cost-effective analog-to-digital converter (ADC) from the company's Burr-Brown product line, which uses delta-sigma architecture to guarantee 24 bits of no missing code (NMC) performance. Designed for high-performance and low-power, the data converter can operate from 2.7V to 5.25V, allowing for power consumption as low as 570 micro-watts.

The ADS1240 provides an unmatched price/performance solution for high-resolution measurement applications such as industrial process control, portable instrumentation, liquid/gas chromatography, blood analysis, weight scales, smart transmitters, and pressure transducers.

"Priced at $3.60 in 1,000 piece quantities, the ADS1240 offers a tremendous value which affords use in a wide variety of high-resolution applications -- from low end to high end, from low volume to high volume," said Robert Schreiber, strategic marketing engineer of Burr-Brown Data Converter products from TI. "This device will allow designers to use a single component for all of their data conversion systems, thereby reducing design time and manufacturing costs, and eliminating system compatibility issues."

The 4-channel ADS1240 and its companion 8-channel ADS1241 are an instrumentation design engineer's dream products: As well as providing an analog input range of -0.1 V to Vdd + 0.1 V, internal buffering can be enabled to provide a high input impedance for the direct connection of transducers or low-level voltage signals; the input range then becomes Analog Ground +0.05 V to Vdd - 1.5 V. The input current with the buffer on is 0.5 nA, while the differential input impedance with the buffer off is 5/PGA Mohms, where the PGA (programmable gain amplifier) can be set from 1 to 128. Burn out current sources are also provided to detect open or shorted sensors, and a bit DAC provides an offset correction with a range of 50% of the full-scale range (FSR).

Conversion in the parts uses a second-order delta-sigma modulator and programmable sinc filter. The reference input is differential and can be used for ratiometric conversions, as well as providing offset to the input of the PGA. The parts are fully characterized at 3 and 5 V with the essential differences only being, as expected, in the worsening of noise performance at 3 V, and the doubling of the numbers for offset error, offset drift, gain error, and gain error drift. The common-mode rejection ratios (CMRRs) are stunning with, for example, 130 dB of rejection of 60 Hz CM with data at 15 Hz. The external master clock rate can be between 1 and 5 MHz. The worst case power consumption is with the PGA set at 128 and the buffer on when the current is 1.225 mA max.