Analog Devices Inc. DC976A

Overview

DC976A from Analog Devices (formerly Linear Technology) is a demonstration circuit for the LT3476EUHF quad buck LED driver IC, configured to drive four independent high-power LED strings with adjustable current up to 1.05A per channel and 27V maximum string voltage. It operates at 1MHz switching frequency, delivers up to 100W total output power, and supports true-color PWM dimming with 1000:1 ratio - used in architectural lighting, automotive headlamp prototypes, and display backlight evaluation.

For engineers reviewing the DC976A datasheet, DC976A pinout, DC976A application, or DC976A equivalent, this page provides verified functional context, measured efficiency data (96% at 1.05A), thermal de-rating guidance, PWM/ANALOG dimming interface details, and confirmed compatibility with Luxeon III and 1W LEDs - all critical for LED driver selection and system integration.

Technical Context

The DC976A implements the LT3476EUHF in a fully assembled, tested buck-mode topology with four independent current-regulated channels. Each channel uses external MOSFETs and inductors, with VADJ resistor dividers setting output current from 350mA (default) to 1.05A. Input separation (VIN for bias, PVIN for power) enables efficient low-voltage control and high-voltage LED driving.

Switching frequency is set to 1MHz via R11 (21kΩ), yielding 84% minimum duty cycle and 96% peak efficiency at 1.05A. The board supports both PWM dimming (100Hz–1kHz, 1000:1 ratio) and analog dimming via VADJ, with dedicated PWM1–PWM4 inputs and LEDn+/LEDn− terminals per channel.

Key Specifications

Availability

DC976A is available at Aetrix Electronics and suitable for LED lighting prototyping, automotive headlamp development, and display backlight validation requiring stable component supply, traceable sourcing, and documented thermal performance.

Supply support for DC976A 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 acquired Linear Technology in 2017 and maintains its legacy of high-performance analog, power management, and signal conditioning ICs.

The DC976A belongs to Linear's demonstration circuit portfolio, designed specifically to accelerate evaluation and adoption of the LT3476 family of multi-channel LED drivers in high-brightness lighting applications.

FAQ

What is the primary function of the DC976A?

The DC976A is a fully assembled demonstration circuit built around the LT3476EUHF quad buck LED driver IC. It provides a ready-to-use platform for evaluating four independent, current-regulated LED channels - each configurable from 350mA to 1.05A - with validated thermal behavior, PWM dimming, and efficiency metrics. DC976A is not a standalone IC but a reference design enabling rapid validation of LED driver performance before custom PCB development.

Can the DC976A drive 1W and 3W LEDs simultaneously?

Yes, the DC976A supports mixed LED types across its four channels, but current must be set per channel to match LED ratings: 350mA maximum for 1W LEDs (e.g., Luxeon) and up to 1.05A for 3W LEDs (e.g., Luxeon III). Thermal de-rating must be applied per channel based on ambient temperature and heatsinking - DC976A includes thermal pads and layout provisions to support both configurations without hardware modification.

What are the input voltage requirements for DC976A operation?

The DC976A requires two separate DC inputs: PVIN (up to 33V) powers the LED strings, while VIN (2.8V–16V) supplies the LT3476EUHF's internal bias circuitry. For optimal efficiency, VIN should be 3.3V or 5V; PVIN must exceed the total forward voltage of the connected LED string plus margin. Exceeding 33V on PVIN triggers overvoltage protection and disables operation.

How does PWM dimming work on the DC976A?

DC976A supports true-color PWM dimming via four dedicated inputs (PWM1–PWM4), each controlling one LED channel independently. With a 100Hz–1kHz square wave, it achieves 1000:1 dimming ratio without color shift. To enable, disconnect the respective PWMn from VIN and connect to an external pulse generator. Removing R20–R23 further reduces LED turn-off time for faster response - a feature validated in the DC976A quick start guide.

Is the DC976A RoHS-compliant and lead-free?

Yes, the DC976A conforms to RoHS Directive 2011/65/EU and uses lead-free solder and components throughout. All PCBs, passives, and the LT3476EUHF IC are marked with appropriate compliance identifiers. Analog Devices certifies the LT3476EUHF as lead-free and halogen-free; DC976A inherits that status as an official Linear Technology demo board manufactured under the same quality and environmental controls.