Analog Devices Inc. LTC2447CUHF#PBF

Overview

LTC2447CUHF#PBF from Analog Devices (formerly Linear Technology) is a 24-bit, 8-channel delta-sigma ADC with selectable differential reference inputs and integrated multiplexer for ratiometric sensor digitization. It delivers 200nV_RMS noise at 13.8Hz, 0.0005% INL, <5µV offset over 0°C to 70°C, and supports up to 8kHz output rate in 2× mode - ideal for high-precision bridge, RTD, and thermocouple measurement systems.

For engineers reviewing the LTC2447CUHF#PBF datasheet, LTC2447CUHF#PBF pinout, LTC2447CUHF#PBF application, or LTC2447CUHF#PBF equivalent, key selection criteria include its five independent differential reference inputs, MUXOUT/ADCIN support for external buffering, no-latency conversion architecture, and guaranteed modulator stability across all input/reference conditions.

Technical Context

The LTC2447CUHF#PBF implements a proprietary 3rd-order delta-sigma modulator with decimating FIR filter and on-the-fly auto-calibration of offset and full-scale every conversion cycle. Its 4-wire serial interface enables real-time channel, reference, speed, and resolution reconfiguration without settling delay.

It features dual SCK modes (internal or external), a dedicated MUXOUT/ADCIN path for external gain/buffering with automatic calibration compensation, and five selectable differential reference inputs - four paired with input channels (VREF01–VREF67) plus one global VREFG - enabling true ratiometric measurements across mixed sensor types.

Key Specifications

Pinout & Package

38-lead (5mm × 7mm) plastic QFN package with exposed thermal pad (Pin 39 = GND). All seven ground pins (1, 4, 5, 6, 31, 32, 33) must be soldered to PCB ground plane for optimal noise performance and thermal dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7177-2 and LTC2449CUHF#PBF, the LTC2447CUHF#PBF uniquely balances 24-bit precision, five independent differential reference inputs, and MUXOUT/ADCIN support for external buffering - making it optimal for cost-sensitive, multi-sensor ratiometric systems requiring field-replaceable front-end gain stages.

Availability

LTC2447CUHF#PBF is available at Aetrix Electronics and suitable for industrial weigh scales, pressure transducer systems, and direct temperature measurement applications requiring stable component supply, long-term lifecycle continuity, and traceable sourcing.

Supply support for LTC2447CUHF#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LTC2447CUHF#PBF belongs to the LTC244x family of high-speed, multichannel delta-sigma ADCs designed specifically for precision industrial and instrumentation applications demanding ratiometric accuracy, low noise, and flexible sensor interfacing.

FAQ

What is the primary function of the MUXOUT/ADCIN pins on the LTC2447CUHF#PBF?

The MUXOUTP/N (Pins 24/27) and ADCINP/N (Pins 25/26) form a dedicated signal path that routes the selected analog input - after multiplexing but before delta-sigma modulation - to an external buffer or amplifier. This allows gain, filtering, or level-shifting outside the ADC core while preserving the LTC2447CUHF#PBF's per-conversion auto-calibration, which automatically cancels offset errors introduced by the external circuitry.

Does the LTC2447CUHF#PBF require external components for basic operation?

No, the LTC2447CUHF#PBF operates fully functional with only a 10µF tantalum and 0.1µF ceramic capacitor on VCC, proper grounding of all GND pins (including the exposed pad), and connection of CS, SCK, SDI, and SDO for communication. Its internal oscillator eliminates need for external crystals or clocks, and the integrated reference multiplexer removes requirement for external analog switches or reference buffers in most ratiometric applications.

How does the LTC2447CUHF#PBF achieve no-latency conversion?

The LTC2447CUHF#PBF achieves no-latency conversion through its proprietary delta-sigma architecture with real-time auto-calibration and absence of digital filter settling delay. Each 32-bit output corresponds exactly to the immediately completed conversion cycle - there is no pipeline depth or group delay. This is confirmed by the datasheet stating "the first conversion following a speed, resolution, channel change or reference change is valid" with zero settling time between conversions.

What is the significance of the five differential reference inputs on the LTC2447CUHF#PBF?

The five differential reference inputs (four channel-paired + one global) enable true independent ratiometric measurement across diverse sensors - e.g., RTDs referenced to one excitation source, strain gauges to another, and thermocouples to a third - all within a single LTC2447CUHF#PBF. This eliminates external reference switching, reduces PCB complexity, and prevents cross-talk or timing skew between reference and signal paths that degrade ratiometric accuracy.

Can the LTC2447CUHF#PBF operate with a single-ended input configuration?

Yes, the LTC2447CUHF#PBF supports single-ended operation using the COM pin (Pin 7) as the common negative input for CH0–CH7. In this mode, each channel measures voltage relative to COM, with full differential input range (±0.5•VREF) preserved. The device maintains its specified 200nV_RMS noise, <5µV offset, and 0.0005% INL performance in single-ended mode, provided the common-mode voltage remains within GND–0.3V to VCC+0.3V.