LTC2484IDD#TRPBF 24-Bit Delta-Sigma ADC with Easy Drive Technology

Designed as a high‑performance 24‑bit ADC, the LTC2484IDD#TRPBF is a precision ADC that combines a 24‑bit No Latency ΔΣ™ analog‑to‑digital converter with patented Easy Drive™ technology. Categorized as a precision measurement IC within Analog Devices' (formerly Linear Technology) delta‑sigma converter portfolio, this device is available in a compact 10‑lead DFN (3mm × 3mm) surface‑mount package (IDD suffix), optimised for space‑constrained PCB layouts and automated SMT assembly. The LTC2484 enables direct digitisation of high‑impedance sensors with full accuracy, making it an ideal building block for precision instrumentation, industrial process control, and direct sensor digitisation applications.

The core advantage of this precision ADC lies in its Easy Drive™ input current cancellation technology, which eliminates dynamic input current errors and the shortcomings of on‑chip buffering through automatic cancellation of differential input current. This patented sampling scheme allows large external source impedances and input signals with rail‑to‑rail input range to be directly digitised while maintaining exceptional DC accuracy. Unlike conventional delta‑sigma converters that suffer from varying input currents that compromise measurement accuracy with high‑impedance sensors, the LTC2484 maintains 600nV_RMS noise performance and 2ppm INL with no missing codes, regardless of the source impedance. This significantly simplifies front‑end signal conditioning and reduces hardware development cycles for precision measurement systems.

At the heart of the LTC2484 is a 24‑bit delta‑sigma modulator with an on‑chip trimmed oscillator, eliminating the need for external crystals or oscillators. The device offers a wide common mode input range from GND to V_CC, independent of the reference voltage. The reference voltage can be as low as 100mV or can be tied directly to V_CC, providing exceptional flexibility for ratiometric measurements. The LTC2484 can be configured to reject line frequencies with programmable 50Hz, 60Hz or simultaneous 50Hz/60Hz rejection mode, as well as a selectable 2× speed‑up mode (15Hz using the internal oscillator). The digital filter settles in a single cycle (No Latency™), enabling immediate accurate conversion results after a channel change or multiplexer switching.

The LTC2484 is equipped with comprehensive accuracy and calibration features as standard. Absolute accuracy and low drift are automatically maintained through continuous, transparent, offset and full‑scale calibration. Key specifications include 1ppm offset and 15ppm total unadjusted error, delivering outstanding measurement integrity over time and temperature. The device's robust design is further reflected in its operating temperature range, covering ‑40°C to 85°C for the industrial grade (IDD suffix), ensuring stable performance under harsh environmental conditions. The 10‑lead DFN package offers excellent thermal performance and a minimal PCB footprint, making it suitable for portable and space‑sensitive instrumentation.

The LTC2484 accepts a wide supply range from 2.7V to 5.5V on a single supply, adapting to various low‑power system rails. Key electrical specifications include a 7.5Hz output rate (or 15Hz in 2× speed mode), differential inputs for enhanced noise rejection, and an SPI serial interface for straightforward connection to microcontrollers and DSPs. The device supports rail‑to‑rail input and reference common mode range, and its internal oscillator simplifies system design by removing the need for external clock components. The component complies with RoHS environmental directives and is available in tape‑and‑reel packaging (TR suffix) for high‑volume automated assembly.

Product variant comparison - The LTC2484 is offered in multiple orderable variants that differ primarily in temperature grade and packaging format. The LTC2484IDD series (I = industrial temperature grade) is rated for operation from ‑40°C to 85°C, making it suitable for demanding industrial and outdoor environments. The LTC2484CDD series (C = commercial temperature grade) is rated for 0°C to 70°C, offering a cost‑optimised option for benign operating conditions. Both variants share identical electrical performance, including 24‑bit resolution, 600nV_RMS noise, 2ppm INL, and the patented Easy Drive™ input current cancellation technology. Packaging options include #PBF (lead‑free tube packaging) and #TRPBF (lead‑free tape‑and‑reel packaging), with the latter optimised for high‑volume automated assembly. The following table summarises the key differentiators among LTC2484 orderable variants:

For replacement considerations, the LTC2484IDD#PBF (tube packaging) is electrically identical to the #TRPBF variant, differing only in packaging format - the #PBF version is supplied in tubes suitable for prototype builds and low‑volume production, while the #TRPBF version is supplied in tape‑and‑reel packaging for high‑volume automated pick‑and‑place assembly. For less demanding environments with ambient temperatures not exceeding 70°C, the LTC2484CDD variants (0°C to 70°C) offer a more cost‑effective alternative while delivering the same 24‑bit precision and Easy Drive™ performance. All four variants share the same 10‑lead DFN (3mm × 3mm) footprint, enabling straightforward design migration between temperature grades and packaging options without PCB layout changes.

Common application scenarios for this 24‑bit ADC include direct sensor digitisation, weight scales, direct temperature measurement, strain gauge transducers, precision instrumentation, industrial process control, DVMs and meters. Typical use cases involve interfacing the LTC2484 directly with high‑impedance sensors such as thermistors, RTDs, and bridge sensors without the need for external buffers or amplifiers. The device's Easy Drive™ technology and wide common mode range make it particularly well‑suited for applications that demand both high resolution and rugged performance-such as precision temperature sensing in industrial environments, battery monitoring in portable equipment, and load cell measurement in weighing systems. Thanks to its patented input current cancellation, 600nV_RMS noise floor, 2ppm INL, and flexible 50Hz/60Hz rejection, the LTC2484IDD#TRPBF has become a trusted choice for engineers seeking a versatile, accurate, and reliable precision ADC-one that delivers the measurement integrity of a laboratory‑grade instrument with the simplicity and compact footprint of a 3mm × 3mm 24‑bit ADC IC, all while eliminating the design complexities traditionally associated with high‑impedance sensor interfacing.