V62/12611-01XE

Based on the single-channel ADS1271, the ADS1278 (octal) is a 24-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC) with data rates up to 128 k samples per second (SPS), allowing simultaneous sampling of eight channels.

Traditionally, industrial delta-sigma ADCs offering good drift performance use digital filters with large passband droop. As a result, they have limited signal bandwidth and are mostly suited for dc measurements. High-resolution ADCs in audio applications offer larger usable bandwidths, but the offset and drift specifications are significantly weaker than respective industrial counterparts. The ADS1278 combines these types of converters, allowing high-precision industrial measurement with excellent dc and ac specifications.

The high-order, chopper-stabilized modulator achieves very low drift with low in-band noise. The onboard decimation filter suppresses modulator and signal out-of-band noise. These ADCs provide a usable signal bandwidth up to 90% of the Nyquist rate with less than 0.005 dB of ripple.

Four operating modes allow for optimization of speed, resolution, and power. All operations are controlled directly by pins; there are no registers to program. The device is fully specified over the military temperature range (–55°C to 125°C) and is available in an HTQFP-64 PowerPAD package.

Key Features

• Simultaneously Measure Eight Channels
• Up to 128-kSPS Data Rate
• AC Performance:
  62-kHz Bandwidth
  111-dB SNR (High-Resolution Mode)
  –108-dB THD
• DC Accuracy:
  0.8-µV/°C Offset Drift
  1.3-ppm/°C Gain Drift
• Selectable Operating Modes:
  High-Speed: 128 kSPS, 106 dB SNR
  High-Resolution: 52 kSPS, 111 dB SNR
  Low-Power: 52 kSPS, 31 mW/ch
  Low-Speed: 10 kSPS, 7 mW/ch
• Linear Phase Digital Filter
• SPI or Frame-Sync Serial Interface
• Low Sampling Aperture Error
• Modulator Output Option (digital filter bypass)
• Analog Supply: 5 V
• Digital Core: 1.8 V
• I/O Supply: 1.8 V to 3.3 V
• Currently Available in an HTQFP-64 PowerPAD package

• Controlled Baseline
• One Assembly/Test Site
• One Fabrication Site
• Available in Military (–55°C/125°C) Temperature Range⁽¹⁾
• Extended Product Life Cycle
• Extended Product-Change Notification
• Product Traceability