24-bit ADCs address precision industrial apps

Dallas, Tex. — Texas Instruments Inc. has introduced two multi-channel, 24-bit industrial analog-to-digital converters (ADCs). Exhibiting excellent DC accuracy and AC performance, the ADS1274 (4-channel) and ADS1278 (8-channel) provide a delta-sigma, simultaneous-sampling measurement system for demanding multi-channel signal acquisition applications such as vibration analysis, medical monitoring, industrial and energy metering equipment.

The ADS1274 and ADS1278 feature a 62 kHz bandwidth, 0.8 uV/C offset drift and up to 111 dB signal-to-noise ratio (SNR). Four operating modes allow for optimization of speed (128 kSPS data rate), resolution (111dB SNR) and power dissipation (7mW/channel mode).

The high-order, chopper-stabilized modulator achieves very low drift and low noise over the signal bandwidth of DC up to the Nyquist frequency. The on-board decimation filter suppresses modulator and out-of-band noise, providing a usable signal bandwidth up to 90 percent of the Nyquist rate with less than 0.005 dB of ripple.

A selectable frame-sync or SPI serial interface provides for convenient interfacing to DSPs, FPGAs and microcontrollers. Either interface supports daisy chaining to simplify readback of multiple ADS1274s or ADS1278s in high-channel count systems. The ADCs are fully specified over the extended industrial range of -40°C to +125°C for the ADS1274 and -40°C to +105°C for the ADS1278.

Traditionally, industrial delta-sigma ADCs offering good drift performance use digital filters with large passband droop, resulting in limited signal bandwidth and mostly suited for DC measurements, said TI. High-resolution ADCs for audio applications offer larger usable bandwidths, but the offset and drift specifications are significantly worse (and often unspecified) than their industrial counterparts, added the company. The ADS1274 and ADS1278 combine these two types of converters, allowing high-precision industrial measurements with excellent DC and AC specifications, said the company.

The ADS1274 and ADS1278 are optimized to work with TI's high-performance TMS320 DSP platforms. TI also has a range of amplifiers such as the OPA1632 and OPA350, which are well suited to work with these ADCs.

Pricing: Suggested resale pricing for the ADS1274 starts at $13.95 in quantities of 1,000, and pricing for the ADS1278 starts at $23.95 in quantities of 1,000. Evaluation modules are available.
Availability: The ADS1274 and ADS1278 are available now from TI and its authorized distributors in HTQFP-64 packages.
Product information: Product information: ADS1274 and ADS1278

Texas Instruments Inc. , 1-800-477-8924,

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