Analog Devices Inc. DC798B

Overview

LTC2480 from Analog Devices (acquired Linear Technology) is a 16-bit plus sign no-latency delta-sigma ADC with patented Easy Drive input current cancellation. It features programmable gain (1–256), simultaneous 50Hz/60Hz line rejection, rail-to-rail input range (0V to VCC), internal oscillator, and operates from 2.7V to 5.5V supply. It directly digitizes high-impedance sensors-e.g., strain gauges or load cells-with 2 ppm INL and 1 ppm offset error, enabling precision industrial weighing systems.

For engineers reviewing the LTC2480 datasheet, LTC2480 pinout, LTC2480 application, or LTC2480 equivalent, this page delivers verified technical context, real-world design meaning for each specification, validated pin functions, application-specific implementation guidance, and two confirmed alternative ADCs with documented functional trade-offs for sensor interface designs requiring high DC accuracy and low power.

Technical Context

The LTC2480 implements a third-order delta-sigma modulator with automatic on-chip offset and full-scale calibration, eliminating latency in digital filter settling. Its Easy Drive sampling scheme cancels differential input current dynamically, enabling direct connection to sources up to 100 kΩ without external buffering while preserving DC accuracy.

It supports dual clocking modes: internal oscillator (307.2 kHz nominal) or external clock via fO pin, allowing precise control of conversion time (131–165 ms in normal mode; 66–82 ms in 2x speed mode) and configurable line-frequency rejection (50 Hz, 60 Hz, or simultaneous). The 4-wire SPI-compatible interface uses CS, SCK, SDI, and SDO pins with programmable configuration bits for gain, input selection, and speed mode.

Key Specifications

Pinout & Package

Available in 10-lead DFN (3 mm × 3 mm) and MSOP packages; exposed pad (Pin 11 in DFN) must be soldered to PCB ground for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS124S08 and MAX11206, the LTC2480 uniquely integrates line-frequency rejection, an internal oscillator, and Easy Drive technology - delivering complete sensor-to-digital functionality in one chip with minimal external components and lowest sleep current among comparable 16-bit+ delta-sigma ADCs.

Availability

LTC2480 is available at Aetrix Electronics and suitable for weight scales, strain gauge interfaces, direct temperature measurement, and industrial process control systems requiring stable component supply across extended temperature ranges (–40°C to 125°C).

Supply support for LTC2480 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 LTC2480 belongs to ADI's precision delta-sigma ADC product line, designed specifically for high-accuracy, low-power sensor digitization in harsh environments where input buffering, external clocks, and calibration complexity must be minimized.

FAQ

What is the maximum source impedance the LTC2480 can drive without accuracy loss?

The LTC2480's Easy Drive technology cancels differential input current, enabling accurate digitization of signals from sources up to 100 kΩ without external buffering. This is confirmed by the +FS error vs RSOURCE plot (Figure TA04) showing <±20 ppm error at 100 kΩ with VCC = 5 V, VREF = 5 V, and TA = 25°C. The LTC2480 maintains this performance across its full –40°C to 125°C operating range.

Does the LTC2480 require an external crystal or oscillator?

No, the LTC2480 includes an on-chip trimmed oscillator that runs at 307.2 kHz when the fO pin is tied to GND. This eliminates the need for external crystals, oscillators, or timing components. External clocking is optional via the fO pin for custom data rates or enhanced line rejection, but not required for standard operation of the LTC2480.

Can the LTC2480 measure its own die temperature?

Yes, the LTC2480 integrates a PTAT (proportional-to-absolute-temperature) sensor that outputs ~420 mV at 27°C, with ±10 mV variation over –40°C to 125°C. This internal temperature reading is selectable via the SDI pin configuration and can be used for system-level drift compensation or health monitoring - a feature confirmed in the "APPLICATIONS INFORMATION" section and Figure G26 of the LTC2480 datasheet.

What is the conversion time of the LTC2480 in simultaneous 50Hz/60Hz rejection mode?

In simultaneous 50Hz/60Hz rejection mode with the internal oscillator, the LTC2480 has a typical conversion time of 146.9 ms (H-grade: 151.0 ms) in normal speed mode, and 73.6 ms (H-grade: 75.6 ms) in 2x speed mode. These values are specified in the TIMING CHARACTERISTICS table (page 5) and confirmed across all temperature grades in the LTC2480 datasheet.

How does the LTC2480 handle reference voltage range limitations?

The LTC2480 accepts reference voltages from 0.1 V to VCC, enabling use of low-voltage references (e.g., 1.25 V bandgap) or direct connection to VCC. Its full-scale range is ±0.5 × VREF / GAIN, so with minimum VREF = 0.1 V and max gain = 256, it supports differential input spans down to ±195 µV - verified in the ANALOG INPUT AND REFERENCE section (page 4) under FS parameter definition.