Analog Devices Inc. LTC2428CG#PBF

Overview

LTC2428CG#PBF from Analog Devices (formerly Linear Technology) is an 8-channel, 20-bit micropower delta-sigma ADC with no-latency digital filtering, integrated oscillator, 8ppm INL, and 1.2ppm RMS noise. It operates from 2.7V to 5.5V, accepts reference voltages from 0.1V to VCC, and delivers valid first-conversion accuracy after channel change-enabling high-precision sensor data acquisition in weight scales and industrial process control.

For engineers reviewing the LTC2428CG#PBF datasheet, LTC2428CG#PBF pinout, LTC2428CG#PBF application, or LTC2428CG#PBF equivalent, key selection considerations include its 110dB 50/60Hz notch rejection, extended input range (–12.5% to +112.5% VREF), single-cycle filter settling, 200µA supply current, and SPI/MICROWIRE-compatible 4-wire interface.

Technical Context

The LTC2428CG#PBF implements a decimating FIR filter synchronized to an internal oscillator or user-supplied external clock (1Hz–800Hz), enabling programmable line-frequency rejection. Its auto-calibrating architecture performs offset and full-scale correction every conversion cycle without interrupting operation.

It integrates an 8-channel analog multiplexer with 250Ω on-resistance (at 2.7V), 120dB channel-to-channel isolation, and break-before-make timing of 290ns. The ADCIN/MUXOUT signal path supports live-zero operation via independent FSSET and ZSSET pins, allowing seamless accommodation of sensor offset and overrange conditions.

Key Specifications

Pinout & Package

Package: 28-lead plastic SSOP (G package), 5.6mm × 10.2mm, 0.635mm pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-precision, low-power ADC applications.

Compared with LTC2408CG#PBF, the LTC2428CG#PBF trades 32-bit depth for faster throughput and simpler data handling; compared with ADS1248IPWR, it offers superior line-rejection and sensor offset tolerance at the cost of no integrated PGA.

Availability

LTC2428CG#PBF is available at Aetrix Electronics and suitable for weight scales, industrial process control, and portable gas analyzers requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant manufacturing.

Supply support for LTC2428CG#PBF 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 LTC2428CG#PBF belongs to ADI's precision delta-sigma ADC product line, designed specifically for low-power, high-accuracy sensor interface applications where line-frequency rejection, zero-drift stability, and multiplexed channel integrity are critical.

FAQ

What is the operating temperature range for the LTC2428CG#PBF?

The LTC2428CG#PBF is specified for operation from 0°C to 70°C (Commercial grade). Its absolute maximum junction temperature is 125°C, and thermal resistance θJA is 130°C/W. Performance parameters including INL, offset drift, and noise are guaranteed across this full range, with typical characterization data provided at –55°C, –45°C, 25°C, and 90°C for design margining.

Does the LTC2428CG#PBF require external passive components for its internal oscillator?

No, the LTC2428CG#PBF does not require any external passive components for its internal oscillator. The oscillator is fully integrated and factory-trimmed to deliver precise 50Hz or 60Hz notch rejection when the FO pin is tied to VCC or GND. This eliminates crystals, capacitors, or resistors traditionally needed for line-frequency rejection in precision ADCs.

How does the LTC2428CG#PBF handle channel switching during continuous conversion?

The LTC2428CG#PBF guarantees that the first conversion after a channel change is valid and corresponds to the newly selected input. Its no-latency delta-sigma architecture ensures single-cycle digital filter settling-unlike conventional sigma-delta converters that require multiple dummy conversions before valid data appears. This behavior is inherent to the LTC2428CG#PBF's decimating FIR filter design and requires no software delay or discard logic.

Can the LTC2428CG#PBF interface directly with a 3.3V microcontroller SPI port?

Yes, the LTC2428CG#PBF supports 3.3V operation and is SPI/MICROWIRE-compatible. Its digital inputs accept VIH ≥ 2.0V (for VCC = 2.7–3.3V) and VIL ≤ 0.6V, matching standard 3.3V logic thresholds. SDO output drives VOH ≥ VCC – 0.5V and VOL ≤ 0.4V under load, ensuring reliable level compatibility without translators. The 4-wire interface (CSADC, SCK, SDO, DIN) operates synchronously with the microcontroller's clock.

What is the purpose of the FSSET and ZSSET pins on the LTC2428CG#PBF?

The FSSET and ZSSET pins define the full-scale and zero-scale reference points independently, establishing VREF = FSSET – ZSSET. This "live zero" architecture allows the LTC2428CG#PBF to accommodate sensor offsets and amplifier errors by extending the usable input range to –12.5% VREF to +112.5% VREF. For example, grounding ZSSET and applying 2.5V to FSSET yields VREF = 2.5V and an input range of –0.3125V to +2.8125V-enabling direct connection to biased transducer outputs.