Analog Devices Inc. DC448A

Overview

DC448A from Analog Devices (formerly Linear Technology) is a demonstration circuit for a dual-output isolated DC/DC power supply, featuring the LT3710 secondary-side synchronous post-regulator controller, LT3781 two-switch forward primary controller, and LTC1698 3.3V output feedback driver. It delivers 3.3V@10A and selectable 1.8V or 2.5V@10A from a 36–72V input, with 1500VDC isolation and 86–87% efficiency at full load.

For engineers reviewing the DC448A datasheet, DC448A pinout, DC448A application, or DC448A equivalent, this board enables rapid evaluation of high-efficiency, tightly regulated dual-rail isolated power architectures for telecom, industrial, and embedded systems requiring precise low-voltage sequencing and thermal robustness without forced airflow.

Technical Context

The DC448A implements a two-switch forward converter topology with synchronous rectification on both outputs. Primary-side regulation of the 3.3V rail uses optocoupler-isolated feedback via LTC1698 to LT3781, while the second output (1.8V/2.5V) is directly regulated by the LT3710 on the secondary side-eliminating need for an additional post-regulator inductor and capacitor.

It integrates discrete Si7892DP PowerPAK SO-8 MOSFETs for synchronous rectification, a Pulse PA0191 planar transformer (PQ20 core), and comprehensive protection including input UVLO/OVP, 3.3V OVP, output current limiting, and board overtemperature shutdown. Switching frequency is fixed at 230kHz.

Key Specifications

Availability

DC448A is available at Aetrix Electronics and suitable for telecom power system validation, industrial PLC power architecture prototyping, and FPGA-based embedded computing platform development requiring stable component supply and documented reference design implementation.

Supply support for DC448A 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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, communications, and industrial markets.

The DC448A belongs to Linear Technology's Demonstration Circuit (DC) series-engineered to showcase validated, production-ready power architectures using their controller ICs, enabling fast, risk-reduced design-in of complex isolated converters.

FAQ

What is the purpose of the DC448A demonstration circuit?

The DC448A demonstration circuit is a fully assembled, tested half-brick PCB that validates a dual-output isolated DC/DC power supply architecture using the LT3710, LT3781, and LTC1698 controllers. It enables engineers to evaluate real-world performance-including efficiency, regulation, ripple, thermal behavior, and protection features-before designing custom power stages. The DC448A is not a production component but a reference design vehicle for rapid prototyping and specification verification of high-density isolated supplies.

How do I configure the second output voltage on the DC448A?

The second output voltage on the DC448A is selected via two jumpers: JP1 and JP2. Both must be placed in the same position-either "1.8V" or "2.5V"-to set VOUT2 to 1.83V ±2% or 2.53V ±2%, respectively. This configuration determines the feedback divider network for the LT3710 regulator. Default factory setting is 1.8V. Changing the selection requires power-off and physical repositioning of both jumpers; no firmware or software adjustment is involved.

Does the DC448A support remote on/off control?

Yes, the DC448A supports logic-level remote on/off control via the ON/OFF pin. Applying a logic low voltage ≤0.6V to this pin relative to –Vin disables the converter; leaving it open or applying ≥1V enables operation. This signal is referenced to the primary-side ground and does not require isolation. The control interface is compatible with standard digital I/O from microcontrollers or system supervisors, enabling coordinated power sequencing in multi-rail systems using the DC448A.

Can the 3.3V output voltage be adjusted on the DC448A?

Yes, the 3.3V output on the DC448A can be trimmed by ±5% using the Vo1 Trim pin. Connecting a resistor divider between Vo1 Trim and Vo RTN adjusts the feedback reference: 0V yields –5% (3.135V), and 3.3V yields +5% (3.465V). The trim function is implemented via the LTC1698 error amplifier and optocoupler feedback path. No hardware modification is required-only external resistor connection to the designated test point, preserving full regulation accuracy across the adjustment range.

What thermal performance can be expected from the DC448A under full load?

At 48V input and full 10A load on both outputs with no airflow, the DC448A achieves thermal equilibrium with a maximum temperature rise of 50°C above ambient at the hottest spot-the PA0191 planar transformer (T1). All other components-including Si7892DP MOSFETs and output capacitors-remain within safe operating limits. This confirms suitability for convection-cooled applications in enclosed industrial enclosures or telecom shelf environments where forced cooling is unavailable or undesirable.