Analog Devices Inc. DC1011A-C

Overview

LTC2494 from Analog Devices (acquired Linear Technology) is a 16-bit, 16-channel delta-sigma ADC with integrated PGA, Easy Drive input current cancellation, and on-chip temperature sensor. It supports up to 8 differential or 16 single-ended inputs, delivers 600nV RMS noise, 2ppm INL, and operates from 2.7V to 5.5V supply. It enables direct digitization of rail-to-rail, high-impedance sensor signals in precision industrial data acquisition systems.

For engineers reviewing the LTC2494 datasheet, LTC2494 pinout, LTC2494 application, or LTC2494 equivalent, key selection considerations include its programmable gain (1–256), simultaneous 50Hz/60Hz rejection mode, no-latency digital filter settling, internal oscillator, and GND-to-VCC input common-mode range independent of reference voltage.

Technical Context

The LTC2494 employs a 3rd-order delta-sigma modulator with decimating FIR filter and auto-calibration engine, achieving true 16-bit resolution without missing codes. Its patented Easy Drive sampling scheme cancels differential input current dynamically, eliminating buffer requirements for high-Z sources.

It integrates a 38-pin QFN package with dedicated MUXOUTP/MUXOUTN outputs, ADCINP/ADCINN analog inputs, and configurable SPI interface (internal or external SCK). The device supports two speed modes: 1x (15.7ms conversion time in 50Hz rejection) and 2x (7.9ms), with corresponding trade-offs in noise (0.6µV vs 0.85µV RMS) and max gain (256 vs 128).

Key Specifications

Pinout & Package

Package: 38-lead (5mm × 7mm) plastic QFN with exposed thermal pad (Pin 39 = GND, must be soldered).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS124S08 and MAX11206, the LTC2494 trades raw resolution for integrated functionality-combining 16-channel flexibility, on-die temperature sensing, and Easy Drive-making it optimal for compact, self-compensating industrial DAQ where channel density and system-level integration matter most.

Availability

LTC2494 is available at Aetrix Electronics and suitable for industrial process control, portable instrumentation, and sensor fusion systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LTC2494 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 LTC2494 belongs to ADI's precision delta-sigma ADC product line, designed specifically for high-accuracy, low-power, multichannel data acquisition in space- and power-constrained industrial and portable equipment.

FAQ

What is the maximum number of analog input channels supported by the LTC2494?

The LTC2494 supports up to 16 single-ended or 8 differential analog input channels. Channel selection is programmable via the SDI serial interface, and the first conversion after channel change is valid due to its no-latency digital filter architecture. This makes the LTC2494 suitable for multiplexed sensor arrays in industrial monitoring and test equipment where rapid channel switching is required without settling delays.

Does the LTC2494 require an external reference voltage?

The LTC2494 does not require an external reference - it operates with a user-supplied differential reference (REF+ and REF–) ranging from 0.1V to VCC, but it also supports internal reference derivation when paired with external components. However, the device itself contains no internal voltage reference; the reference must be provided externally. The LTC2494's GND-to-VCC input common-mode range is independent of this reference voltage, simplifying system design.

How does the Easy Drive technology in the LTC2494 improve measurement accuracy with high-impedance sensors?

Easy Drive technology in the LTC2494 automatically cancels differential input current during sampling, eliminating dynamic errors that would otherwise occur with high-source-impedance sensors (e.g., pH electrodes or thermopiles). This allows rail-to-rail input signals to be digitized directly - without external op-amp buffers - while preserving DC accuracy, including 0.5µV offset and 2ppm INL. The result is simplified front-end design and improved long-term stability.

Can the LTC2494 perform simultaneous 50Hz and 60Hz line frequency rejection?

Yes, the LTC2494 supports a dedicated simultaneous 50Hz/60Hz rejection mode, configured via the SDI interface. In this mode, the digital filter nulls both frequencies in a single conversion cycle (144.1ms typical), making it ideal for globally deployed instrumentation used in regions with either mains standard - without requiring hardware changes or firmware reconfiguration.

What is the function of the fO pin on the LTC2494?

The fO pin on the LTC2494 controls the conversion clock source: tying fO to GND selects the internal 307.2kHz oscillator, while applying an external square wave enables precise data rate tuning and custom rejection null placement. This flexibility allows optimization for specific noise environments or synchronization with system clocks - all without modifying the PCB layout or adding external timing components.