Analog Devices Inc. DC289A

Overview

DC289A from Analog Devices is a demonstration board for the LTC1701 synchronous step-down DC/DC converter IC, featuring a 2.5V–5.5V input range, jumper-selectable 1.5V/2.5V/3.3V or adjustable output, 0.5A load capability, and operation in Burst Mode™ for high light-load efficiency. It is designed for portable electronics powered by single Li-Ion or 3–4 NiCd/NiMH cells.

For engineers reviewing the DC289A datasheet, DC289A pinout, DC289A application, or DC289A equivalent, this evaluation board enables rapid validation of LTC1701-based buck regulator performance-including transient response, dropout behavior, and low-quiescent-current shutdown-under real-world battery-powered conditions.

Technical Context

The DC289A implements the LTC1701's constant off-time, current-mode control architecture with an internal P-channel MOSFET switching at ~1MHz. Its design supports seamless transition between PWM and Burst Mode™ based on load current to sustain >85% efficiency down to 1mA output.

Dropout operation is achieved via 100% duty cycle control, enabling VOUT ≅ VIN with minimal voltage loss. The ITH/RUN pin provides both current limit threshold setting and enable/shutdown functionality, requiring careful external capacitance management to preserve transient response.

Key Specifications

Availability

DC289A is available at Aetrix Electronics and suitable for portable power management, battery-powered instrumentation, and embedded microcontroller supply applications requiring stable component supply and fast evaluation turnaround.

Supply support for DC289A 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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies.

The DC289A belongs to Analog Devices' Linear Technology demonstration board portfolio, engineered specifically to accelerate design-in of their high-efficiency, low-voltage DC/DC converters for space-constrained portable systems.

FAQ

What is the primary function of the DC289A demonstration board?

The DC289A demonstration board is a fully assembled and tested evaluation platform for the LTC1701 step-down DC/DC converter. It enables engineers to validate key performance metrics-including efficiency across load range, transient response to load steps, and shutdown/quiescent current-without designing a custom PCB. The DC289A directly implements the recommended layout and component selection from the LTC1701 datasheet.

How do I configure the output voltage on the DC289A?

Output voltage on the DC289A is set using jumper JP1: position "1.5" selects 1.5V, "2.5" selects 2.5V, "3.3" selects 3.3V, and "ADJ" enables user-defined output via resistor R7. When using ADJ mode, the feedback divider must be calculated per the LTC1701's VFB = 1.25V reference. The DC289A includes pads and silkscreen guidance for R7 placement and value selection.

What is the role of the ITH/RUN pin on the DC289A?

The ITH/RUN pin on the DC289A serves dual functions: it sets the current limit threshold when used as ITH, and acts as an enable/shutdown control when pulled low. On the DC289A, this pin is accessible via a test point and can be grounded externally to achieve <1µA shutdown current. Excessive capacitance on this node must be avoided to prevent degradation of load transient response.

Does the DC289A support dropout operation, and how is it implemented?

Yes, the DC289A supports dropout operation through the LTC1701's internal P-channel MOSFET, which operates at 100% duty cycle when VIN approaches VOUT. This allows VOUT to track VIN closely (VOUT ≅ VIN − VDS(on)), maximizing usable battery capacity in deep discharge conditions. The DC289A demonstrates this behavior without requiring external components or configuration changes.

Can the DC289A be used to evaluate thermal performance under continuous 0.5A load?

Yes, the DC289A is rated for continuous 0.5A output and includes thermal relief on critical copper pours to support sustained operation. Its compact 0.3-inch² footprint and optimized layout allow realistic thermal assessment of the LTC1701 in SOT-23 packaging. For accurate measurement, ambient temperature, airflow, and PCB copper area must match intended end-application conditions-data collected on the DC289A informs thermal design margins for final systems using the same IC.