Analog Devices Inc. DC1925A-A

Overview

LTC2378-20 from Analog Devices (formerly Linear Technology) is a 20-bit, 1 Msps successive approximation register (SAR) analog-to-digital converter with ±0.5 ppm typical integral nonlinearity, 104 dB SNR at 2 kHz, and digital gain compression (DGC) functionality. It operates from a 2.5 V supply, supports ±V_REF fully differential input range (V_REF = 2.5 V to 5.1 V), and consumes only 21 mW at full throughput - enabling high-precision data acquisition in medical imaging and portable instrumentation.

For engineers reviewing the LTC2378-20 datasheet, LTC2378-20 pinout, LTC2378-20 application, or LTC2378-20 equivalent, key selection criteria include guaranteed 20-bit no-missing-codes performance, internal conversion clock eliminating external timing constraints, SPI-compatible serial interface with daisy-chain mode, and DGC-enabled single-supply amplifier drive capability.

Technical Context

The LTC2378-20 implements a charge-redistribution SAR architecture with a 20-bit CDAC and differential comparator, achieving no pipeline delay and zero cycle latency. Its internal oscillator fixes conversion time at 675 ns, while auto power-down between conversions scales quiescent current from 21 mW (1 Msps) to 21 µW (1 ksps).

Digital Gain Compression (DGC) remaps the ADC's transfer function so zero-scale shifts from 0 V to 0.1·V_REF and full-scale from V_REF to 0.9·V_REF, enabling rail-to-rail input swing compatibility with single 5.5 V–supplied op-amps without negative rails. The SPI interface supports 1.8 V to 5 V I/O logic and configurable CHAIN/RDL/SDI pin behavior for normal or daisy-chain operation.

Key Specifications

Pinout & Package

The LTC2378-20 is available in two RoHS-compliant packages: 16-lead MSOP (3 mm × 4.9 mm) and 16-lead 4 mm × 3 mm DFN with exposed pad (GND). Both packages support operation from –40°C to +85°C (I-grade) or 0°C to +70°C (C-grade).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-resolution SAR ADC applications.

Compared with AD7985 and ADS8860, the LTC2378-20 uniquely combines 20-bit resolution, 104 dB SNR, and DGC in a single 2.5 V–supplied device - making it the only option that preserves full resolution while enabling true single-supply analog front-end design without performance trade-offs.

Availability

LTC2378-20 is available at Aetrix Electronics and suitable for medical imaging systems, high-speed data acquisition platforms, and portable instrumentation requiring stable component supply with long-term lifecycle assurance.

Supply support for LTC2378-20 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 LTC2378-20 belongs to ADI's ultra-precision SAR ADC product line, designed specifically for applications demanding 20-bit accuracy, low power, and seamless integration into compact, high-density signal chains.

FAQ

What is the maximum sampling rate of the LTC2378-20?

The LTC2378-20 achieves a maximum sampling rate of 1 Msps with no pipeline delay or cycle latency. Its internal oscillator fixes conversion time at 675 ns, and the minimum time between conversions is 1 µs - enabling deterministic, jitter-free sampling for time-critical applications such as ATE and real-time control. This rate is guaranteed across the full operating temperature range (–40°C to +85°C) for I-grade variants.

Does the LTC2378-20 require an external clock source?

No, the LTC2378-20 does not require an external clock source. It integrates an internal oscillator that sets the conversion timing, eliminating external clock generation circuitry and associated layout complexity. The SCK pin is used solely for SPI data transfer timing and operates independently of the conversion clock - supporting flexible host interface clocking from 1.8 V to 5 V logic levels.

How does Digital Gain Compression (DGC) work in the LTC2378-20?

Digital Gain Compression (DGC) in the LTC2378-20 is enabled by grounding the REF/DGC pin. When active, it digitally remaps the ADC transfer function so zero-scale corresponds to 0.1·V_REF and full-scale to 0.9·V_REF, effectively compressing the usable input range to 0.5 V–4.5 V for a 5 V reference. This eliminates the need for a negative supply in the driving amplifier while preserving all 20 bits of resolution - confirmed in the datasheet's DGC-enabled SNR and INL specifications.

What package options are available for the LTC2378-20?

The LTC2378-20 is offered in two surface-mount packages: the 16-lead plastic MSOP (3 mm × 4.9 mm) and the 16-lead 4 mm × 3 mm plastic DFN with exposed thermal pad. Both packages support industrial temperature ranges (–40°C to +85°C) in I-grade versions (e.g., LTC2378IMS-20#TRPBF and LTC2378IDE-20#TRPBF) and commercial ranges (0°C to +70°C) in C-grade versions.

Is the LTC2378-20 pin-compatible with other members of the LTC2378 family?

Yes, all LTC2378-x variants (e.g., LTC2378-18, LTC2378-16) share identical pinouts, package footprints, and serial interface protocols. Differences are limited to resolution, sampling rate, and corresponding dynamic performance specs - allowing hardware reuse across designs targeting different precision/speed trade-offs. The LTC2378-20 pin configuration is explicitly validated in the datasheet's Pin Configuration section for both MSOP and DFN packages.