Analog Devices Inc. DC1011A-A

Overview

LTC2498 from Analog Devices (formerly Linear Technology) is a 24-bit, 16-channel (8-differential) delta-sigma ADC with Easy Drive input current cancellation, integrated temperature sensor (±2°C absolute accuracy), and programmable 50/60Hz rejection - used in high-precision industrial data acquisition systems requiring rail-to-rail inputs and zero differential input current.

For engineers reviewing the LTC2498 datasheet, LTC2498 pinout, LTC2498 application, or LTC2498 equivalent, this page delivers verified specifications, validated pin functions, real-world use scenarios for sensor digitization and temperature-compensated measurement, and confirmed alternative parts with documented technical differences.

Technical Context

The LTC2498 employs a 3rd-order delta-sigma modulator with decimating FIR filter and auto-calibration engine that continuously removes offset and drift of external amplifiers shared across all 16 analog inputs. Its patented Easy Drive sampling scheme cancels differential input current dynamically, enabling direct digitization of rail-to-rail signals from high-impedance sources without buffer degradation.

It supports both internal (307.2 kHz) and external oscillator modes, offers simultaneous 50 Hz/60 Hz rejection, and delivers no-latency conversion settling in a single digital filter cycle-even after channel changes. The device operates from 2.7V to 5.5V and integrates a PTAT temperature sensor with 1/30°C resolution.

Key Specifications

Pinout & Package

38-lead (5mm × 7mm) plastic QFN package with exposed pad (Pin 39 = GND). All ground pins (Pins 1, 3–6, 31–33) must be soldered to PCB ground plane; exposed pad is electrically GND and thermally critical.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS1258IRTCR and AD7768-1ACPZ, the LTC2498 uniquely combines 16-channel multiplexing, on-die temperature sensing, simultaneous 50/60 Hz rejection, and Easy Drive technology - making it optimal for compact, self-calibrating, EMI-resilient sensor hubs where channel count and DC precision outweigh raw speed.

Availability

LTC2498 is available at Aetrix Electronics and suitable for high-precision data acquisition, industrial process control, and portable environmental sensing requiring stable component supply and long-term manufacturing continuity.

Supply support for LTC2498 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 semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC2498 belongs to ADI's precision delta-sigma ADC product line, designed specifically for low-power, multi-channel, high-accuracy sensor digitization in harsh EMI environments - emphasizing ease of use, rail-to-rail operation, and built-in system-level compensation.

FAQ

What is the maximum input source impedance supported by the LTC2498 without accuracy degradation?

The LTC2498 supports input source impedances up to 1 MΩ while maintaining full 24-bit accuracy and 2 ppm INL, thanks to its patented Easy Drive input current cancellation architecture. This eliminates dynamic input current errors that would otherwise cause gain and offset errors in high-Z sensor interfaces like RTDs or pH electrodes. The LTC2498 achieves this without external buffers - directly digitizing rail-to-rail signals even with mismatched source impedances on IN+ and IN–.

Does the LTC2498 require an external reference voltage, or can it operate with an internal reference?

The LTC2498 does not include an internal reference; it requires an external differential reference applied to REF+ and REF– pins. The reference voltage range is 0.1V to VCC, and the device supports ratiometric or absolute reference configurations. For example, a 2.5V reference yields ±1.25V full-scale differential input range. The LTC2498 itself provides no voltage reference - users must supply a stable, low-noise external reference such as the LT6654 or ADR45xx series to achieve specified 0.5 µV offset and 2 ppm INL performance.

How does the LTC2498 handle temperature compensation in multi-sensor systems?

The LTC2498 integrates a calibrated on-die PTAT temperature sensor (93.5 µV/°C, ±2°C absolute accuracy) that can be read alongside analog channel conversions. In multi-sensor systems, this enables real-time die temperature measurement for compensating gain/offset drift of external signal conditioning circuitry. The LTC2498 supports automatic interleaving: e.g., measure CH0, then internal temp, then CH1 - all within the same SPI transaction. This eliminates need for separate thermal sensors and simplifies firmware-driven compensation algorithms.

Can the LTC2498 perform simultaneous 50 Hz and 60 Hz line frequency rejection, and how is it configured?

Yes, the LTC2498 supports simultaneous 50 Hz and 60 Hz rejection via its programmable digital filter - activated by setting the appropriate configuration bits via SDI during SPI command. This mode uses a composite null at both frequencies, achieving >87 dB rejection without external hardware. It is selected independently of clock source (internal or external oscillator) and remains effective across the full operating temperature range (–40°C to 125°C for H-grade). The LTC2498 implements this in silicon using a tailored FIR decimation filter structure, not software-based FFT or averaging.

What is the minimum and maximum conversion time for the LTC2498 in normal-speed mode with internal oscillator?

In normal-speed mode with internal oscillator (307.2 kHz), the LTC2498's conversion time is 131 ms for 60 Hz rejection, 157.2 ms for 50 Hz rejection, and 144.1 ms for simultaneous 50/60 Hz rejection. These values are guaranteed over the full temperature range for all grades (C/I/H). Conversion time scales inversely with external oscillator frequency - e.g., at 614.4 kHz, times halve. The LTC2498 guarantees first-conversion validity immediately after channel selection, with no additional settling delay.