Analog Devices Inc. DC2222A-A

Overview

LTC2500-32 from Analog Devices (formerly Linear Technology) is a 32-bit oversampling successive approximation register (SAR) analog-to-digital converter with integrated configurable digital filter, operating from a single 2.5V supply and supporting ±VREF differential input range up to ±5.1V. It delivers dual simultaneous outputs: a 32-bit digitally filtered low-noise code (SDOA) and a 32-bit no-latency composite code (SDOB) comprising 24-bit differential + 7-bit common-mode data with overrange detection. It is used in high-precision seismic data acquisition systems requiring ultra-low INL and high dynamic range.

For engineers reviewing the LTC2500-32 datasheet, LTC2500-32 pinout, LTC2500-32 application, or LTC2500-32 equivalent, key selection criteria include guaranteed 32-bit no-missing-codes performance, ±0.5 ppm typical INL, 148 dB dynamic range at 61 sps, configurable decimation filters (DF = 4–16384), and dual-output timing behavior-especially where latency-critical control loops coexist with high-resolution post-processing paths.

Technical Context

The LTC2500-32 implements a SAR ADC core followed by a programmable digital lowpass filter (SINC1–SINC4, SSINC) that downsamples and filters the raw conversion stream to produce the high-precision 32-bit SDOA output. Filter configuration-including down-sampling factor (4 to 16384), filter type, and synchronization-is controlled via SPI-compatible serial interface using SDI/SCKA/RDLA signals.

Its dual-output architecture separates real-time monitoring (via 1 Msps SDOB with zero-cycle latency) from precision measurement (via filtered SDOA with variable data rate down to 250 ksps). The device supports multi-device synchronization via SYNC pin and features wide common-mode input range (0 V to VREF), relaxed anti-aliasing requirements, and operation across –40°C to 85°C.

Key Specifications

Pinout & Package

24-lead 7 mm × 4 mm plastic DFN package (DKD) with exposed ground pad (Pin 25). Pin functions are validated per Linear/ADI official datasheet Rev. FB (250032fb).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-resolution ADC applications.

Compared with AD7768-1 and ADS131M08, the LTC2500-32 uniquely combines guaranteed 32-bit resolution, dual-output timing, and field-programmable digital filtering - making it irreplaceable in applications demanding simultaneous real-time responsiveness and metrology-grade precision without external FPGA-based post-processing.

Availability

LTC2500-32 is available at Aetrix Electronics and suitable for seismology, energy exploration, and high-accuracy instrumentation requiring stable component supply, long-lifecycle availability, and traceable sourcing for safety-critical deployments.

Supply support for LTC2500-32 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The LTC2500-32 belongs to ADI's precision data acquisition product line, designed specifically for applications demanding ultra-low noise, high linearity, and deterministic timing - such as geophysical sensing, metrology, and automated test equipment.

FAQ

What is the primary function of the LTC2500-32 in a signal chain?

The LTC2500-32 serves as a high-precision analog-to-digital converter that digitizes differential analog inputs with up to 32-bit resolution. Its dual-output architecture delivers both a low-latency 32-bit composite code (SDOB) for real-time monitoring and a digitally filtered 32-bit high-precision code (SDOA) for post-processing. The LTC2500-32 integrates a configurable digital filter, eliminating the need for external FPGA-based decimation and simplifying system-level noise management in applications like seismic data acquisition.

How does the LTC2500-32 achieve 148 dB dynamic range at 61 sps?

The LTC2500-32 achieves 148 dB dynamic range at 61 sps by combining its 32-bit SAR core with a highly configurable digital lowpass filter (e.g., SSINC with DF = 16384) that suppresses out-of-band noise through oversampling and decimation. This architecture effectively increases effective number of bits (ENOB) beyond the physical resolution limit. The LTC2500-32 maintains this performance across temperature and supply variations, with verified test data confirming 148 dB DR at 61 sps with VREF = 5 V and DF = 1024.

Can the LTC2500-32 operate with a 3.3 V I/O interface while using a 2.5 V analog supply?

Yes, the LTC2500-32 supports independent analog and digital supplies: VDD = 2.5 V powers the SAR core and reference circuitry, while OVDD = 1.71 V to 5.25 V powers all digital I/O pins (SDOA, SDOB, SCKA, SCKB, RDLA, RDLB, etc.). When OVDD = 3.3 V, all digital signals comply with 3.3 V logic levels, enabling direct connection to 3.3 V FPGAs or microcontrollers without level shifters. The LTC2500-32 datasheet explicitly validates timing and drive strength at OVDD = 3.3 V.

What is the role of the SYNC pin on the LTC2500-32?

The SYNC pin on the LTC2500-32 provides deterministic phase alignment of the internal digital filter across multiple devices. A synchronous edge applied to SYNC resets the decimation counter and aligns filter response timing - ensuring coherent sampling and identical group delay in multi-channel systems such as phased seismic arrays or synchronized data loggers. This capability is essential for time-of-flight measurements and beamforming, and is validated in the LTC2500-32 functional block diagram and timing specifications.

Does the LTC2500-32 require external anti-aliasing filtering?

The LTC2500-32 significantly relaxes anti-aliasing filter requirements due to its integrated digital lowpass filter, which attenuates out-of-band energy before decimation. While a minimal RC filter (e.g., 10 Ω + 1 nF) is recommended at the analog inputs to limit broadband noise and prevent aliasing from frequencies above the Nyquist zone of the final output rate, a traditional sharp cutoff analog filter is unnecessary. The LTC2500-32 datasheet confirms this in the "Relaxed Anti-Aliasing Filter Requirements" feature and Applications Information section.