Texas Instruments ADS1235/ADS1235-Q1 Delta-Sigma ADC

Texas Instruments ADS1235/ADS1235-Q1 Precision 7200SPS Delta-Sigma (ΔΣ) Analog-to-Digital Converter (ADC) comes with an integrated programmable gain amplifier (PGA). This device also includes diagnostic features such as PGA over range and reference monitors. The ADC provides high-accuracy, zero-drift conversion data for high-precision equipment, including weighing scales, strain gauges, and resistive pressure sensors.

The ADC has signal and reference multiplexers supporting three differential and two reference inputs. The ADC also includes a low-noise PGA that provides gains of 1, 64, and 128 and a 24-bit ΔΣ modulator and programmable digital filter. The high-impedance inputs (1GΩ) of the PGA reduce measurement error that is caused by sensor loading.

The ADC supports ac-bridge excitation to remove the drift errors from the sensor wiring. The ADC provides the clock control signals for the ac-excitation operation. The flexible digital filter is programmable for single-cycle settled conversions and provides 50Hz and 60Hz line cycle rejection at the same time. The ADS1235-Q1 devices are AEC-Q100 qualified for automotive applications.

Features

  • 24-Bit, High-precision ADC
    • 120,000 Noise-free counts (10mV input, 10SPS)
    • Offset drift of 1nV/°C
    • Gain drift of 0.5ppm/°C
  • Three differential or five single-ended inputs
  • Two reference inputs
  • ±7mV to ±5V Wide input voltage range
  • Low-noise PGA, Gain of 1, 64, and 128
  • Data rate of 2.5 SPS to 7200SPS
  • AC or DC-Bridge excitation option
  • Chop mode for zero drift operation
  • Simultaneous 50Hz and 60Hz rejection mode
  • Single-cycle settling mode
  • Missing reference input monitor
  • Signal over-range monitor
  • Temperature sensor
  • Cyclic Redundancy Check (CRC)
  • 5V or ±2.5V Power supply

Applications

  • Weigh scales and strain-gauge digitizers
  • Dynamic weigh systems
  • Pressure measurement
  • Process analytics

Functional Block Diagram

Block Diagram - Texas Instruments ADS1235/ADS1235-Q1 Delta-Sigma ADC
Published: 2018-10-26 | Updated: 2023-07-14