ADS1235 24-bit, 7.2kSPS, 5-ch delta-sigma ADC with PGA and AC excitation for low-noise bridge sensors | TI.com

ADS1235 (ACTIVE)

24-bit, 7.2kSPS, 5-ch delta-sigma ADC with PGA and AC excitation for low-noise bridge sensors

 

Description

The ADS1235 is a precision, 7200-SPS, delta-sigma (ΔΣ) analog-to-digital converter (ADC) with an integrated programmable gain amplifier (PGA). This device also includes diagnostic features such as PGA overrange and reference monitors. The ADC provides high-accuracy, zero-drift conversion data for high-precision equipment, including weigh scales, strain gauges, and resistive pressure sensors.

The ADC has signal and reference multiplexers that support three differential signal inputs and two reference inputs. The ADC also includes a low-noise PGA that provides gains of 1, 64, and 128. The ADC also has a 24-bit ΔΣ modulator and programmable digital filter.

The high-impedance inputs (1 GΩ) 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 50-Hz and 60-Hz line cycle rejection at the same time.

The ADS1235 is available in a 5-mm × 5-mm QFN package, and is specified across the –40°C to +125°C temperature range.

 

Features

  • 24-Bit, High-Precision ADC
    • 120,000 Noise-Free Counts
      (10-mV Input, 10 SPS)
    • Offset Drift: 1 nV/°C
    • Gain Drift: 0.5 ppm/°C
  • Three Differential or Five Single-Ended Inputs
  • Two Reference Inputs
  • Wide Input Voltage Range: ±7 mV to ±5 V
  • Low-Noise PGA, Gain: 1, 64, and 128
  • Data Rate: 2.5 SPS to 7200 SPS
  • AC- or DC-Bridge Excitation Option
  • Chop Mode for Zero Drift Operation
  • Simultaneous 50-Hz and 60-Hz Rejection Mode
  • Single-Cycle Settling Mode
  • Missing Reference Input Monitor
  • Signal Overrange Monitor
  • Temperature Sensor
  • Cyclic Redundancy Check (CRC)
  • 5-V or ±2.5-V Power Supply

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Parametrics Compare all products in Precision ADCs (<=10MSPS)

 
Resolution (Bits)
Sample Rate (Max) (kSPS)
Number of input channels
Interface
Operating temperature range (C)
Package Group
Approx. price (US$)
Power consumption (Typ) (mW)
Package size: mm2:W x L (PKG)
Architecture
Input type
Multi-channel configuration
Reference mode
Features
Input range (Max) (V)
Input range (Min) (V)
Analog voltage AVDD (Min) (V)
Analog voltage AVDD (Max) (V)
Digital supply (Min) (V)
Digital supply (Max) (V)
Rating
ADS1235 ADS1232 ADS1234
24     24     24    
7.2     0.08     0.08    
5     2     4    
SPI     SPI     SPI    
-40 to 125     -40 to 105     -40 to 105    
VQFN | 32     TSSOP | 24     TSSOP | 28    
4.80 | 1ku     3.90 | 1ku     4.25 | 1ku    
23     4.3     4.3    
32VQFN: 25 mm2: 5 x 5 (VQFN | 32)     24TSSOP: 50 mm2: 6.4 x 7.8 (TSSOP | 24)     28TSSOP: 62 mm2: 6.4 x 9.7 (TSSOP | 28)    
Delta-Sigma     Delta-Sigma     Delta-Sigma    
Differential
Single-Ended    
Differential     Differential    
Multiplexed     Multiplexed     Multiplexed    
Ext     Ext     Ext    
50/60 Hz Rejection
GPIO
Oscillator
PGA
Temp Sensor    
50/60 Hz Rejection
Oscillator
PGA    
50/60 Hz Rejection
Oscillator
PGA    
2.5
5    
2.5     2.5    
-2.5
0    
0     0    
-2.5
4.75    
2.7     2.7    
2.5
5.25    
5.3     5.3    
2.7     2.7     2.7    
5.25     5.3     5.3    
Catalog     Catalog     Catalog