Analog Devices Inc. EV-LT6655-REFZ

Overview

EV-LT6655-REFZ from Analog Devices is a precision voltage reference evaluation daughter board designed for high-accuracy DAC applications, featuring the LTC6655 low-noise, low-drift 5 V reference IC (2 ppm/°C max drift, 1.25 µV_p-p noise), integrated with ADA4077-2 op-amps for buffered output and gain inversion, and used to supply ±V_REF to the AD5791 20-bit DAC on the EVAL-AD5791SDZ platform.

For engineers reviewing the EV-LT6655-REFZ datasheet, EV-LT6655-REFZ pinout, EV-LT6655-REFZ application, or EV-LT6655-REFZ equivalent, this board enables validation of ultra-low INL performance in precision voltage-output DAC systems, supports dual-rail reference generation (±V_REF), and integrates thermal and layout-optimized signal conditioning for metrology-grade measurements.

Technical Context

The EV-LT6655-REFZ implements a precision reference subsystem that accepts the LTC6655's 5 V output and conditions it via matched ADA4077-2 amplifiers to generate symmetrical ±5 V reference rails (V_REFP, V_REFN) routed to the AD5791 DAC. It uses thermally stable resistor networks and low-thermal-EMF PCB layout practices to preserve the LTC6655's 0.1 ppm/V line regulation and 1.25 µV_p-p noise specification.

This daughter board interfaces exclusively via three 10-pin Mill-Max connectors (J1, J4, J9) to the EVAL-AD5791SDZ carrier board, delivering isolated analog reference paths with dedicated AGND routing and star-grounding topology to minimize ground loop error-critical for sub-1 LSB INL measurement integrity at 20-bit resolution.

Key Specifications

Availability

EV-LT6655-REFZ is available at Aetrix Electronics and suitable for precision DAC evaluation, metrology instrument calibration, automated test equipment (ATE) reference subsystems, and high-resolution data acquisition requiring stable component supply and traceable reference performance.

Supply support for EV-LT6655-REFZ 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. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA, serving precision instrumentation, industrial automation, and communications markets.

The EV-LT6655-REFZ belongs to Analog Devices' precision reference evaluation board family, engineered specifically to validate ultra-low-drift voltage references in high-resolution DAC and ADC signal chains where thermal stability and noise floor are design-critical.

FAQ

What is the primary function of the EV-LT6655-REFZ?

The EV-LT6655-REFZ is a dedicated voltage reference daughter board that provides precision ±5 V reference rails (V_REFP, V_REFN) to the AD5791 20-bit DAC on the EVAL-AD5791SDZ platform. It uses the LTC6655-5 reference IC and ADA4077-2 op-amps to deliver low-drift, low-noise, thermally stable reference signals-enabling sub-1 LSB INL performance validation. The EV-LT6655-REFZ does not operate standalone and requires integration with the main evaluation board.

Which reference IC is used on the EV-LT6655-REFZ board?

The EV-LT6655-REFZ board integrates the LTC6655-5, a 5 V precision voltage reference IC from Analog Devices, specified with maximum temperature coefficient of 2 ppm/°C, 1.25 µV_p-p noise (0.1–10 Hz), and 0.1 ppm/V line regulation. This IC forms the core reference source, with its output conditioned by ADA4077-2 amplifiers to generate symmetrical ±5 V rails for the AD5791 DAC.

How does the EV-LT6655-REFZ connect to the EVAL-AD5791SDZ main board?

The EV-LT6655-REFZ connects to the EVAL-AD5791SDZ via three 10-pin Mill-Max socket connectors: J1, J4, and J9, located at the top-right corner of the main board. These provide dedicated paths for AGND, VDD, VSS, VREFP, VREFN, and signal returns. No soldering or wiring is required-the board mounts mechanically and electrically mates through these standardized interconnects.

Can the EV-LT6655-REFZ be used with DACs other than the AD5791?

The EV-LT6655-REFZ is designed and validated specifically for use with the AD5791 on the EVAL-AD5791SDZ platform. Its output levels (±5 V), pinout mapping, and grounding scheme are optimized for that interface. While the LTC6655-5 reference and ADA4077-2 circuitry could theoretically support other precision DACs, no compatibility testing, layout adaptation, or documentation is provided for alternate devices-use with the AD5791 is the only supported configuration for the EV-LT6655-REFZ.

What performance improvement does the EV-LT6655-REFZ provide over the standard EV-ADR445-REFZ board?

Compared to the EV-ADR445-REFZ (which uses the ADR445, 3 ppm/°C drift, 2.25 µV_p-p noise), the EV-LT6655-REFZ delivers lower temperature drift (2 ppm/°C vs. 3 ppm/°C), lower broadband noise (1.25 µV_p-p vs. 2.25 µV_p-p), and improved long-term stability-directly enabling tighter INL performance (≤ ±0.5 LSB typical vs. ≤ ±1 LSB with ADR445) in AD5791-based systems. The EV-LT6655-REFZ also features enhanced thermal layout and matched amplifier gain networks.