Analog Devices Inc. DC379A

Overview

DC379A from Analog Devices (formerly Linear Technology) is a demonstration circuit board designed to evaluate the LTC1606CG - a 16-bit, 250kSPS successive-approximation ADC operating from a single +5V supply with 75mW power consumption. It features on-board LT1468 input amplifier (gain = 2.82), LT1019A-2.5 reference option, and parallel 16-bit data output for high-fidelity analog-to-digital conversion testing in precision instrumentation applications.

For engineers reviewing the DC379A datasheet, DC379A pinout, DC379A application, or DC379A equivalent, this board supports evaluation of SNR (112dB at full scale), THD (–90dB typical with LT1468), aperture jitter sensitivity, anti-aliasing interface design, and reference selection impact on 16-bit ADC performance under real-world signal chain conditions.

Technical Context

The DC379A implements a complete signal chain around the LTC1606CG ADC, including configurable input amplification (JP4), selectable internal/external reference (JP1), clock edge conditioning via U6A + U3 NAND gate, and parallel output buffering/latching (JP5). It supports both buffered (LT1468, 7.44nV/√Hz input-referred noise) and direct-input (10kΩ impedance) signal paths.

It lacks on-board anti-aliasing filtering beyond a non-critical 800kHz RC filter (R4/C16), requiring external anti-aliasing upstream of the amplifier for Nyquist-compliant evaluation. The board is optimized for coherent FFT testing (e.g., 1037.5976Hz input with 250kHz sampling) and validated using low-jitter clock sources and high-linearity signal generators per LTC1606 datasheet Figure 6.

Key Specifications

Availability

DC379A is available at Aetrix Electronics and suitable for precision data acquisition systems, automated test equipment (ATE), industrial process monitoring, and high-resolution sensor interface development requiring stable component supply and proven evaluation platform traceability.

Supply support for DC379A 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, serving precision measurement, communications, and industrial markets.

The DC379A belongs to Linear Technology's Demonstration Circuit (DC) series, engineered specifically to showcase optimal layout, grounding, decoupling, and signal routing practices for high-resolution ADCs in demanding analog-intensive applications.

FAQ

What is the primary function of the DC379A demonstration circuit?

The DC379A demonstration circuit is a fully assembled PCB designed to evaluate the LTC1606CG 16-bit, 250kSPS ADC under real-world signal chain conditions. It provides validated layout, configurable input amplification (LT1468), reference selection, clock conditioning, and parallel data output - enabling accurate measurement of SNR, THD, and spectral performance without custom prototyping. The DC379A serves as a turnkey reference for integrating the LTC1606CG into precision measurement systems.

Does the DC379A include an anti-aliasing filter?

No, the DC379A does not include a functional anti-aliasing filter. While it contains an 800kHz RC network (R4/C16) after the LT1468 amplifier, this stage is explicitly stated in the Quick Start Guide to "not constitute an anti-aliasing filter" and does not suppress frequencies above Nyquist (125kHz). For valid evaluation, external anti-aliasing must be placed upstream of the amplifier or signal source to prevent aliasing distortion in the DC379A's measurements.

What power supplies are required to operate the DC379A?

The DC379A requires three independent supplies: +5V (≈30mA, powers the LTC1606CG ADC directly, no reverse-bias protection), and ±15V (powers the LT1468 amplifier U4). Critically, ±15V must be supplied even when JP4 is set to "OUT" (amplifier bypassed), because unpowered U4 input circuitry will load the signal source and cause distortion. Poor regulation on the +5V rail directly degrades ADC performance.

How is the reference voltage selected on the DC379A?

Reference selection on the DC379A is controlled by jumper JP1: "INT" position uses the LTC1606CG's internal 2.5V reference; "EXT" position routes the LT1019A-2.5 external reference to the ADC. The LT1019A-2.5 offers guaranteed maximum drift specifications versus the internal reference's typical values - making JP1 a critical choice for temperature-sensitive or long-duration precision evaluations using the DC379A.

Can the DC379A be used without the LT1468 amplifier?

Yes, the DC379A can be used without the LT1468 amplifier by setting jumper JP4 to "OUT", which removes U4 from the signal path. In this configuration, the input impedance at J2 is 10kΩ, and only the +5V supply is needed. However, the ±15V supplies remain mandatory to prevent U4's unpowered input stage from loading the signal source and introducing distortion - a key operational constraint documented in the DC379A Quick Start Guide.