Analog Devices Inc. DC3123A

Overview

DC3123A from Analog Devices is an evaluation board for the LTC3315A dual synchronous step-down DC/DC regulator IC, configured to deliver 1.2V/2A and 1.8V/2A outputs from a 3.3V input at 2MHz switching frequency in a 74mm² solution. It supports forced continuous (FC), burst, and pulse-skip modes via JP1 jumper selection and enables external clock synchronization from 1MHz to 3MHz.

For engineers reviewing the DC3123A datasheet, DC3123A pinout, DC3123A application, or DC3123A equivalent, this board serves as a validated reference design for evaluating high-efficiency, high-frequency dual-output power delivery in space-constrained applications such as FPGA core logic, multi-rail SoC supplies, and low-voltage processor subsystems.

Technical Context

The DC3123A implements the LTC3315A - a monolithic, constant-frequency, current-mode buck regulator with two independent 2A channels operating 180° out of phase. Each channel integrates top and bottom MOSFETs, drivers, and control circuitry in a 1.6mm × 1.6mm WLCSP package.

It features a 25ns minimum on-time enabling high VIN-to-low VOUT conversion at up to 3MHz, programmable output voltages from 0.5V to VIN, and precise load regulation (±0.5% over 0–2A load range) verified at 3.3V input in forced continuous mode.

Key Specifications

Availability

DC3123A is available at Aetrix Electronics and suitable for FPGA power delivery, multi-rail embedded processors, high-speed ADC/DAC supplies, and industrial edge AI modules requiring stable component supply and rapid prototyping validation.

Supply support for DC3123A 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, serving precision instrumentation, communications, and power management markets.

The DC3123A belongs to Analog Devices' demonstration circuit product line, designed specifically to accelerate customer evaluation and adoption of the LTC3315A dual buck regulator for compact, high-efficiency, multi-output power solutions.

FAQ

What is the primary function of the DC3123A evaluation board?

The DC3123A evaluation board is a fully assembled and tested reference design for the LTC3315A dual synchronous step-down regulator. Its primary function is to demonstrate and validate the performance of two independent 2A buck channels delivering 1.2V and 1.8V outputs from a 3.3V input. The DC3123A enables engineers to rapidly assess efficiency, transient response, ripple, and mode-switching behavior without designing a custom PCB.

How do I configure the DC3123A for external clock synchronization?

To configure the DC3123A for external clock synchronization, set JP1 to the FC/SYNC position and apply a 0V–3.3V square wave (50% duty cycle) between 1MHz and 3MHz to the MODE/SYNC turret. When synchronized, the LTC3315A operates in forced continuous mode and locks its internal oscillator to the external clock - a capability confirmed in the DC3123A demo manual Rev. 0, Section 4, Steps 11–13. This configuration is implemented directly on the DC3123A board.

Does the DC3123A support adjustable output voltages?

No - the DC3123A is a fixed-output demonstration board: VOUT1 is factory-set to 1.2V and VOUT2 to 1.8V using precision feedback resistors (R1 = 140kΩ, R2/R4 = 100kΩ, R3 = 261kΩ). While the underlying LTC3315A IC supports adjustable outputs from 0.5V to VIN via external resistor dividers, the DC3123A board does not include provisions for reconfiguration. Its purpose is to validate the specified dual-rail solution, not serve as a general-purpose adjustable platform.

What measurement setup is required to accurately capture output ripple on the DC3123A?

To accurately capture output ripple on the DC3123A, connect a 50Ω-terminated oscilloscope probe directly to TP1 (for VOUT1) or TP2 (for VOUT2) using a short 50Ω coax cable - not a standard 1MΩ probe with long ground lead. The DC3123A schematic and demo manual Rev. 0, Section 7, explicitly state that high-frequency noise coupling invalidates measurements taken with conventional probes. The board includes U.FL-compatible pads (TP1/TP2) and 3-terminal EMI filter capacitors (C9/C10) to support this validated 50Ω measurement method.

Can the DC3123A be used for load transient testing, and how is it performed?

Yes - the DC3123A supports controlled load transient testing using the optional transient response circuit shown in Figure 3 of the demo manual. A signal generator drives a MOSFET switch (Q1/Q2) across RSNS1/RSNS2 (100mΩ sense resistors) to create fast current steps (e.g., 0.4A to 1.6A at 1A/µs). VOUT1 and VOUT2 transient responses are captured directly at the output turrets or TP1/TP2. The DC3123A's layout, component selection (including low-ESL capacitors), and integrated sense resistors make it a validated platform for measuring sub-10µs recovery times in forced continuous mode.