Analog Devices Inc. LTC2508IDKD-32#PBF

Overview

LTC2508IDKD-32#PBF from Analog Devices 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 reference. It delivers 145dB dynamic range at 61sps and guarantees no missing codes across its full 32-bit resolution, targeting ultra-high-precision DC and low-frequency measurement systems such as seismic data acquisition and high-accuracy instrumentation.

For engineers reviewing the LTC2508IDKD-32#PBF datasheet, LTC2508IDKD-32#PBF pinout, LTC2508IDKD-32#PBF application, or LTC2508IDKD-32#PBF equivalent, key selection considerations include dual-output architecture (32-bit filtered vs. 22-bit no-latency), pin-strapped down-sampling factor selection (256–16384), wide 0V–VREF common-mode input range, SPI-compatible 1.8V–5V I/O, and guaranteed operation from –40°C to +85°C in a 24-lead 7mm × 4mm DFN package.

Technical Context

The LTC2508IDKD-32#PBF implements a 32-bit SAR core with on-chip charge redistribution DAC and two parallel output paths: one feeding a programmable digital lowpass filter for high-resolution, low-noise measurements, and another bypassing filtering to deliver 14-bit differential + 8-bit common-mode data at 1Msps with zero conversion latency. Its digital filter supports four discrete down-sampling factors (256, 1024, 4096, 16384) selected via SEL0/SEL1 pins, enabling trade-offs between dynamic range (125–145dB) and output data rate (3.9ksps–61sps).

It features fully differential analog inputs with 128dB CMRR at 200Hz, 45pF input capacitance in sample mode, and relaxed anti-aliasing requirements due to the integrated digital filter. Synchronization across multiple devices is supported via the SYNC pin, and power management includes a dedicated power-down mode drawing only 350µA.

Key Specifications

Pinout & Package

Package: 24-lead plastic DFN (7mm × 4mm), exposed pad (Pin 25) connected to GND and required to be soldered to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7177-2 and ADS131M08, the LTC2508IDKD-32#PBF uniquely combines guaranteed 32-bit no-missing-codes performance, dual-output architecture, and ±0.5ppm INL - making it irreplaceable for applications requiring simultaneous high-resolution DC measurement and real-time 1Msps feedback without latency penalties.

Availability

LTC2508IDKD-32#PBF is available at Aetrix Electronics and suitable for seismology data acquisition, energy exploration sensors, and automated test equipment requiring stable component supply, extended temperature operation, and long-term calibration integrity.

Supply support for LTC2508IDKD-32#PBF 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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, communications, automotive, and consumer markets.

The LTC2508IDKD-32#PBF belongs to the Linear Technology (acquired by Analog Devices) precision ADC product line, designed specifically for ultra-high-resolution, low-noise, low-power DC and low-frequency measurement applications where traditional Σ-Δ or pipeline architectures fall short in linearity or latency.

FAQ

What is the operating temperature range for the LTC2508IDKD-32#PBF?

The LTC2508IDKD-32#PBF is rated for industrial operation from –40°C to +85°C. This temperature grade is explicitly defined in the order information table and verified across all key specifications including dynamic range, INL, and power consumption - making it suitable for downhole, outdoor, and factory-floor instrumentation where ambient extremes are expected. The LTC2508CDKD-32#PBF variant covers 0°C to 70°C.

Does the LTC2508IDKD-32#PBF support true bipolar input signals?

Yes, the LTC2508IDKD-32#PBF supports true bipolar operation via its fully differential input architecture with ±VREF range and 0V–VREF common-mode range. When VREF = 5V, IN+ and IN– can swing independently from 0V to 5V, allowing differential inputs from –5V to +5V. This enables direct digitization of traditional bipolar signals without external level-shifting circuitry - a key enabler for precision instrumentation and sensor interfaces.

How does the dual-output architecture of the LTC2508IDKD-32#PBF work?

The LTC2508IDKD-32#PBF provides two independent output paths: SDOA delivers a 32-bit digitally filtered, low-noise code optimized for high-resolution DC measurements, while SDOB delivers a 22-bit no-latency composite code (14-bit differential + 8-bit common-mode) updated every 1µs. These outputs operate simultaneously, allowing real-time system monitoring and closed-loop control using the fast path while accumulating high-precision data from the filtered path - eliminating the need for separate ADCs.

What reference voltage range is supported by the LTC2508IDKD-32#PBF?

The LTC2508IDKD-32#PBF accepts an external reference voltage (VREF) from 2.5V to 5.1V, applied to Pins 8–10 (internally tied). At VREF = 5V, the LSB size is 2.3nV, enabling sub-nanovolt resolution. Reference current draw is 0.7–1mA and scales linearly with sample rate. The wide VREF range allows optimization of dynamic range and noise performance across diverse signal chain designs without changing the ADC itself.

Can multiple LTC2508IDKD-32#PBF devices be synchronized?

Yes, the LTC2508IDKD-32#PBF includes a dedicated SYNC input (Pin 14) that allows precise phase alignment of the internal digital filters across multiple devices. A synchronous edge on SYNC forces all connected LTC2508 units to reset their filter states simultaneously, ensuring coherent oversampling and consistent group delay - essential for phased-array sensing, multi-channel data loggers, and distributed measurement systems requiring time-aligned high-resolution samples.