Analog Devices Inc. LTC2421CMS#TRPBF

Overview

LTC2421CMS#TRPBF from Analog Devices (formerly Linear Technology) is a 1-channel, 20-bit micropower delta-sigma ADC in MSOP-10 package, operating from 2.7V to 5.5V supply. It delivers 8ppm INL, 1.2ppm RMS noise, and no-latency digital filtering with single-cycle settling-enabling precise direct temperature measurement and strain gauge digitization in battery-powered instrumentation.

For engineers reviewing the LTC2421CMS#TRPBF datasheet, LTC2421CMS#TRPBF pinout, LTC2421CMS#TRPBF application, or LTC2421CMS#TRPBF equivalent, key selection criteria include its extended input range (–12.5% to +112.5% VREF), integrated oscillator eliminating external timing components, 50/60Hz notch rejection ≥110dB, and SPI/MICROWIRE-compatible 3-wire interface with automatic calibration per conversion.

Technical Context

The LTC2421CMS#TRPBF implements a proprietary decimating FIR filter architecture that settles in one conversion cycle-eliminating latency typical of conventional ∆Σ ADCs. Its internal oscillator supports user-selectable 50Hz or 60Hz ±2% notch rejection via the FO pin, or external clocking from 2.56kHz to 307.2kHz for custom rejection frequencies.

It uses pseudo-differential bridge digitization with independent zero-scale (ZSSET) and full-scale (FSSET) inputs, enabling live-zero operation and seamless accommodation of sensor offset/gain errors. Each conversion includes on-the-fly offset and full-scale calibration, ensuring stability over temperature, supply voltage, and time without interrupting the conversion cycle.

Key Specifications

Pinout & Package

Package: 10-lead plastic MSOP (MS10), 3 mm × 3 mm × 1.1 mm, exposed pad (not electrically connected), rated for 0°C to 70°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 20-bit micropower delta-sigma ADC applications.

Compared with ADS124S08IPWR and LTC2418CGN#PBF, the LTC2421CMS#TRPBF uniquely combines 20-bit precision, ultra-low 200 µA active current, live-zero programmability, and integrated 50/60 Hz rejection in a 10-pin MSOP-making it optimal for single-sensor, battery-constrained, and offset-prone industrial transducer interfaces.

Availability

LTC2421CMS#TRPBF is available at Aetrix Electronics and suitable for weight scales, direct temperature measurement, and strain gauge transducers requiring stable component supply, long-term calibration integrity, and low-power operation in industrial embedded systems.

Supply support for LTC2421CMS#TRPBF 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 LTC2421CMS#TRPBF belongs to ADI's legacy Linear Technology precision ADC product line, designed specifically for low-power, high-accuracy sensor digitization in instrumentation, process control, and portable test equipment where zero-latency, self-calibrating performance is critical.

FAQ

What is the absolute maximum input voltage range for the LTC2421CMS#TRPBF?

The LTC2421CMS#TRPBF supports an absolute maximum analog input voltage range of –0.3 V to (VCC + 0.3 V). Within this limit, its functional input range is –12.5% to +112.5% of VREF (where VREF = FSSET – ZSSET). Exceeding the absolute maximum may activate ESD protection diodes and increase leakage-induced errors.

Does the LTC2421CMS#TRPBF require external passive components for its internal oscillator?

No, the LTC2421CMS#TRPBF requires no external components for its internal oscillator. The oscillator is fully integrated and automatically configures for 50 Hz rejection (FO = VCC) or 60 Hz rejection (FO = GND). This eliminates crystals, capacitors, or resistors-reducing BOM cost and layout complexity.

How does the LTC2421CMS#TRPBF handle offset and full-scale drift over temperature?

The LTC2421CMS#TRPBF performs automatic offset and full-scale calibration on every conversion cycle. This results in guaranteed drift specifications: 0.04 ppm of VREF/°C for both offset and full-scale error-ensuring stable accuracy from –40°C to 85°C without external calibration routines or temperature compensation algorithms.

Can the LTC2421CMS#TRPBF interface directly with a microcontroller using standard SPI?

Yes, the LTC2421CMS#TRPBF supports SPI and MICROWIRE protocols via its 3-wire interface (CS, SCK, SDO). It operates in either internal-clock mode (SCK output) or external-clock mode (SCK input), and outputs a 24-bit frame (4 status + 20 data bits) MSB-first with EOC signaling-compatible with most MCU SPI peripherals without protocol translation.

Is the LTC2421CMS#TRPBF pin-compatible with earlier Linear Technology ADCs?

Yes, the LTC2421CMS#TRPBF is pin-compatible with the LTC2401CMS#PBF. Both share identical MSOP-10 pinout, supply, reference, and interface connections. While the LTC2421CMS#TRPBF outputs 24 bits (vs. 32 bits for LTC2401), its timing can be matched by adding 8 dummy clock cycles-enabling drop-in replacement in existing designs.