Analog Devices Inc. DC1067A-B

Overview

LTC2450 from Analog Devices (acquired Linear Technology) is a 16-bit delta-sigma analog-to-digital converter with single-ended rail-to-rail input (0 V to VCC), SPI interface, integrated oscillator, and ultra-low power sleep mode (<200 nA). It delivers 2 LSB INL, 0.02 LSB RMS noise, and single-cycle settling for multiplexed sensing in battery-powered environmental monitors and embedded data acquisition systems.

For engineers reviewing the LTC2450 datasheet, LTC2450 pinout, LTC2450 application, or LTC2450 equivalent, key selection considerations include its 33.3 ms conversion time, internal VCC-referenced architecture, 2 mm × 2 mm DFN package with exposed pad, and proprietary low-input-current sampling scheme enabling direct RC filter interfacing without external op-amps.

Technical Context

The LTC2450 employs a delta-sigma modulator core with continuous internal offset and full-scale calibration per conversion, ensuring stability over temperature and time without user intervention. Its reference voltage is tied directly to VCC (2.7 V to 5.5 V), eliminating external references while maintaining 1 LSB resolution across the full supply range.

It operates in three deterministic states-CONVERT (fixed 33.3 ms), SLEEP (sub-200 nA), and DATA OUTPUT (16-bit MSB-first SPI)-with CS-controlled state transitions and optional conversion status monitoring via SDO level during idle. The integrated oscillator eliminates timing component dependencies, and the 50 nA average input sampling current enables <1 LSB error with simple 1 kΩ/0.1 μF RC filters.

Key Specifications

Pinout & Package

Package: 6-lead (2 mm × 2 mm) plastic DFN with exposed pad (Pin 7 = GND, must be soldered to PCB ground plane).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit delta-sigma ADC applications.

Compared with ADS1115IDGSR and MCP3421A0T-E/CH, the LTC2450 uniquely combines rail-to-rail single-ended input, integrated oscillator, sub-200 nA sleep, and SPI simplicity-making it optimal for compact, long-life, single-channel sensing where minimal external components and deterministic timing are critical.

Availability

LTC2450 is available at Aetrix Electronics and suitable for environmental monitoring, embedded data acquisition, and direct temperature measurement applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LTC2450 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 LTC2450 belongs to ADI's precision delta-sigma ADC product line, designed specifically for ultra-low-power, high-accuracy sensing in space- and energy-constrained embedded systems where simplicity, reliability, and minimal external components are essential.

FAQ

What is the maximum sample rate of the LTC2450?

The LTC2450 achieves up to 30 conversions per second, with a typical conversion time of 33.3 ms and maximum of 42 ms. This fixed timing enables predictable system scheduling and eliminates filter settling delays common in other delta-sigma architectures. The LTC2450 does not support variable oversampling ratios - its sample rate is inherently determined by its internal modulator and digital filter design.

Does the LTC2450 require an external reference voltage?

No, the LTC2450 uses its VCC supply as the reference voltage, supporting 2.7 V to 5.5 V operation. This eliminates the need for external precision references, reducing cost and board area. The LTC2450 maintains 1 LSB resolution across the full VCC range, though INL, offset, and full-scale errors improve with higher VCC due to larger μV-per-LSB scaling.

How does the LTC2450 achieve such low input sampling current?

The LTC2450 employs a proprietary input sampling scheme that reduces average input current to 50 nA - several orders of magnitude lower than conventional delta-sigma ADCs. This allows direct interface with high-impedance sensors like thermistors and RTDs without buffer amplifiers. The LTC2450's input capacitance is only 0.35 pF, minimizing charge injection and settling burden on external RC filters.

Can the LTC2450 operate in 2-wire mode?

Yes, the LTC2450 supports 2-wire operation by hardwiring CS to GND. In this mode, SDO status monitoring is retained for CPOL = 1 (idle-high clock), but sleep mode is disabled and abort functionality is lost. The LTC2450 enters DATA OUTPUT immediately after conversion, and new conversions are triggered by the 16th or 17th SCK edge - making it suitable for simple microcontroller implementations with limited GPIO.

What is the purpose of the exposed pad on the LTC2450 DFN package?

The exposed pad (Pin 7) on the LTC2450 is electrically connected to GND and must be soldered to the PCB ground plane. It serves dual purposes: improving thermal dissipation to maintain junction temperature within spec under continuous conversion, and providing a low-inductance ground return path critical for noise immunity in high-resolution analog measurements. Failure to solder the pad degrades both thermal performance and ADC accuracy.