Analog Devices Inc. DC1268B-A

Overview

DC1268B-A from Analog Devices (formerly Linear Technology) is a demonstration circuit board featuring the LT3755EUD-2 high-voltage LED controller in boost topology, supporting 8V–40V input, up to 54V/1A LED output, 400kHz switching frequency, 93% efficiency at 12V_IN/50V_LED, and open-LED overvoltage protection clamping at ~56V. It enables automotive-grade LED lighting evaluation with PWM and analog dimming, shutdown, and soft-start.

For engineers reviewing the DC1268B-A datasheet, DC1268B-A pinout, DC1268B-A application, or DC1268B-A equivalent, this board provides validated reference design for high-brightness LED drivers requiring stable 400kHz operation, robust open-LED fault response, and seamless transition between boost, buck-boost, and SEPIC topologies.

Technical Context

DC1268B-A implements a synchronous boost LED driver using the LT3755EUD-2 IC, which integrates a 7V internal regulator (IntVcc), open-LED status flag, and current-mode control architecture. Its R8 = 28.7k resistor sets 400kHz switching frequency, and RS1 = 0.015Ω sense resistor establishes 6.6A peak switch current limit.

The board supports dual power inputs (PVIN and VIN), with PVIN directly powering the controller and VIN optionally isolated via R2 removal. The CTRL pin enables analog dimming and low-input-voltage current derating, while UVLO disables operation below 8V and the PWM terminal requires active-high assertion for normal operation.

Key Specifications

Availability

DC1268B-A is available at Aetrix Electronics and suitable for automotive LED headlight evaluation, industrial high-brightness signage, architectural accent lighting, and DC-powered horticultural lighting systems requiring stable component supply and rapid prototyping capability.

Supply support for DC1268B-A 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. (including legacy Linear Technology products) designs precision analog, mixed-signal, and power management ICs for high-reliability industrial, automotive, and communications applications.

The DC1268B-A belongs to the LT3755 demonstration circuit family, developed specifically to accelerate validation of high-voltage LED controllers in automotive and commercial lighting systems where input range, fault tolerance, and topology flexibility are critical.

FAQ

What is the primary function of DC1268B-A?

DC1268B-A is a fully assembled demonstration circuit board built around the LT3755EUD-2 controller, configured as a high-efficiency boost LED driver. It delivers constant 1A current to LED strings up to 54V from an 8V–40V input, with integrated open-LED protection, PWM/analog dimming, and 400kHz switching. DC1268B-A serves as a hardware reference for evaluating and adapting the LT3755-2 in real-world lighting designs.

How does DC1268B-A differ from DC1268B-B?

DC1268B-A uses the LT3755EUD-2 IC with an open-LED status output, while DC1268B-B uses the LT3755EUD-1 with a SYNC input for clock synchronization. The boards share identical PCB layout and passive components but differ in the mounted controller and associated signal routing-DC1268B-A exposes the OPENLED pin, whereas DC1268B-B routes the SYNC pin. Both require distinct firmware or external timing coordination depending on system architecture.

Can DC1268B-A be used in buck topology?

Yes, DC1268B-A can be reconfigured for buck topology by modifying the external component layout and feedback network per the LT3755-2 datasheet. The OUT terminal is explicitly designated for this purpose and functions as the buck switch node. However, the default assembly is boost-only; successful buck operation requires replacing the inductor, diode, and compensation network, and verifying stability across the full input/output voltage range.

What is the role of the CTRL pin on DC1268B-A?

The CTRL pin on DC1268B-A provides analog dimming control and automatic low-input-voltage current reduction. When PVIN drops below 9V, the internal circuitry lowers the CTRL voltage to reduce LED current and constrain peak switch current-preventing inductor saturation and MOSFET overstress. An external voltage source can override this behavior for precise analog dimming, independent of input conditions.

Does DC1268B-A include thermal management provisions?

Yes, DC1268B-A leverages the thermally enhanced 16-lead QFN package of the LT3755EUD-2, with its exposed ground pad soldered to a large copper area on the PCB. The board layout follows Linear Technology's "Layout Considerations" guidelines, including minimized high-current loop area, dedicated ground planes, and thermal vias under the IC pad. These features enable reliable operation at full 1A/54W output without forced airflow.