The LTC2500-32 is a low noise, low power, high performance 32-bit ADC with an integrated configurable digital filter. Operating from a single 2.5V supply, the LTC2500-32 features a fully differential input range up to ±VREF, with VREF ranging from 2.5V to 5.1V. This device supports a wide common mode range from 0V to VREF simplifying analogue signal conditioning requirements.

The LTC2500-32 from Linear Technology, now part of Analog Devices, is an ultrahigh precision 32-bit successive approximation register (SAR) analogue-to-digital converter (ADC). It is a new and enabling approach for precision measurement applications, blending the high accuracy and speed of Linear Technology’s proprietary SAR ADC architecture with flexible integrated digital filters to optimize system signal bandwidth and ease analogue anti-aliasing filter requirements.

The LTC2500-32 simultaneously provides two outputs: (1) a high precision 32-bit low noise digitally filtered output that achieves up to 148dB of dynamic range and (2) a 32-bit 1Msps no latency output comprising an over-range detection bit, a 24-bit representation of the input voltage difference, and a 7-bit representation of the common mode input voltage. The no latency output is inherently perfectly matched to the digitally filtered output, avoiding the mismatch and drift that typically occur in applications requiring an additional faster ADC to monitor signal integrity in parallel with a precision ADC. The 32-bit composite output is available each conversion cycle, with no cycle of latency.

The configurable digital filter reduces measurement noise by low-pass filtering and down-sampling the stream of data from the SAR ADC core, giving the 32-bit filtered output. The wide input common mode range and high CMRR enable the LTC2500-32 to interface signals with varying common mode, simplifying the analogue signal chain. Each of the two outputs provides a highly accurate representation of the voltage difference applied between the two input terminals.

The exceptional low noise density of LTC2500-32 produces 148dB of dynamic range at 61sps and 104dB at 1Msps. In addition to low noise, LTC2500-32 offers unrivalled linearity of 0.5ppm typical and 2ppm guaranteed maximum INL, and negligibly low gain and offset drift over wide temperature ranges. In combination, these features enable state-of-the-art high precision measurements in noisy environments, such as in industrial automation applications.

The integrated configurable digital filter offers seven filter types and 13 different down-sampling factors, providing users with a high level of flexibility to trade off bandwidth, filter response and noise performance for each application.

The digital filter is highly configurable through the SPI-compatible interface and features many distinct filter types that suit a variety of applications. The digital low-pass filter relaxes the requirements for analogue anti-aliasing. Multiple LTC2500-32 devices can be easily synchronized using the SYNC pin.

The LTC2500-32 is part of a family of ultrahigh precision SAR ADCs, which also includes the 32-bit LTC2508-32, providing digital filters optimised for data acquisition applications, and the 24-bit LTC2512-24, providing digital filters optimised for signal processing applications requiring a flat passband.

The LTC2512-24 and LTC2508-32 provide a 14-bit no latency output for monitoring signal integrity and four down-sampling factors for trading off bandwidth with dynamic range. The LTC2500-32 provides a broader range of filters and down-sampling factors.

The LTC2500-32 is available in commercial and industrial (–40o C to 85o C) temperature grades. Pricing begins at $35.95 each in 1,000-piece quantities. The DC2222A evaluation board for the LTC2500 SAR ADC family is available at www.linear.com/demo or via a local Linear Technology sales office.

The USA list pricing shown is for budgetary use only. International prices may differ due to local duties, taxes, fees and exchange rates.

For more information, visit www.linear.com/product/LTC2500-32.

 

Summary of Features of the LTC2500-32:

  • 104dB SNR at 1Msps
  • Dual Output 32-Bit SAR ADC

    • 32-Bit Digitally Filtered Low Noise Output
    • 24-Bit Differential + 7-Bit Common Mode 1Msps Output with Over-range Detect
  • Configurable Digital Filter with Synchronization
  • 7 Filter Types: Sinc,1 Sinc,2 Sinc,3 Sinc,4 Spread-Sinc, Flat Passband, Averaging
  • Wide Input Common Mode Range
  • 128dB CMRR
  • 24-Lead 7mm x 4mm DFN Package

 

Typical Application

Applications

  • Seismology
  • Energy Exploration
  • Automatic Test Equipment
  • High Accuracy Instrumentation

 

Linear Technology (UK) Limited

(Now part of Analog Devices)
Tel: +44 (0)1628 477066
 

E-mail: uksales@linear.com 
Web site: www.linear.com 
Website for product information:  http://www.linear.com/product/LTC2500-32