ADS1234 24-Bit, Ultra Low-Noise Analog-to-Digital Converter

The ADS1232 and ADS1234 are precision 24-bit analog-to-digital converters (ADCs). With an onboard, low-noise programmable gain amplifier (PGA), precision delta-sigma ADC and internal oscillator, the ADS1232/4 provide a complete front-end solution for bridge sensor applications including weigh scales, strain gauges and pressure sensors.

The input multiplexer accepts either two (ADS1232) or four (ADS1234) differential inputs. The ADS1232 also includes an onboard temperature sensor to monitor ambient temperature. The onboard, low-noise PGA has a selectable gain of 1, 2, 64, or 128 supporting a full-scale differential input of ±2.5V, ±1.25V, ±39mV, or ±19.5mV. The delta-sigma ADC has 23.5-bit effective resolution and is comprised of a 3rd-order modulator and 4th-order digital filter. Two data rates are supported: 10SPS (with both 50Hz and 60Hz rejection) and 80SPS. The ADS1232/4 can be clocked externally using an oscillator or a crystal. There is also an internal oscillator available that requires no external components. Offset calibration is performed on-demand and the ADS1232/4 can be put in a low-power standby mode or shut off completely in power-down mode. All of the features of the ADS1232/4 are operated through simple pin-driven control. There are no digital registers to program in order to simplify software development. Data are output over an easily-isolated serial interface that connects directly to the MSP430 and other microcontrollers.

The ADS1232 is available in a TSSOP-24 package and the ADS1234 is in a TSSOP-28. Both are fully specified from -40°C to +105°C.

Features

• Complete Front-End for Bridge Sensors
• Up to 23.5 Effective Bits
• Onboard, Low-Noise PGA
• RMS Noise:
  17nV at 10SPS (PGA = 128)
  44nV at 80SPS (PGA = 128)
• 19.2-Bit Noise-Free Resolution at Gain = 64
• Over 100dB Simultaneous 50Hz and 60Hz Rejection
• Flexible Clocking:
  Low-Drift Onboard Oscillator (±3%) Optional External Crystal
• Selectable Gains of 1, 2, 64, and 128
• Easy Ratiometric Measurements—External Voltage Reference up to 5V
• Selectable 10SPS or 80SPS Data Rates
• Two-Channel Differential Input with Built-In Temperature Sensor (ADS1232)
• Four-Channel Differential Input (ADS1234)
• Simple Serial Digital Interface
• Supply Range: 2.7V to 5.3V
• -40°C to +105°C Temperature Range

Applications

• Weigh Scales
• Strain Gauges
• Pressure Sensors
• Industrial Process Control

Parametrics

Diagrams (1)