Analog Devices Inc./Maxim Integrated MAXREFDES48#

Overview

MAXREFDES48# from Maxim Integrated is a fully assembled, tested, and documented isolated 24V-to-12V 40W forward-converter reference design implementing the MAX17599 low-I_Q active-clamp PWM controller. It delivers up to 3.5A at 12V output across an 18V–36V input range, operates at 250kHz, achieves 92.5% peak efficiency at 24V input, and uses an EFD20 core transformer.

For engineers reviewing the MAXREFDES48# datasheet, MAXREFDES48# pinout, MAXREFDES48# application, or MAXREFDES48# equivalent, key selection considerations include its functional insulation rating, active-clamp reset topology, programmable frequency dithering for EMI reduction, EN/UVLO and OVI protection thresholds (16.5V/37.0V), and hiccup-mode overcurrent protection.

Technical Context

The MAXREFDES48# implements a wide-input isolated forward converter with active-clamp transformer reset, enabling reduced switch voltage stress, larger allowable flux swing, and elimination of dissipative snubbers. Its control architecture centers on the MAX17599 IC, which integrates current-mode PWM, soft-start, soft-stop, negative current limiting, and thermal shutdown.

Input protection includes programmable EN/UVLO (set to 16.5V) and OVI (set to 37.0V); fault management employs hiccup-mode overcurrent protection and thermal shutdown. Frequency-dithering capability supports low-EMI spread-spectrum operation in noise-sensitive environments.

Key Specifications

Availability

MAXREFDES48# is available at Aetrix Electronics and suitable for industrial process control, PLC power rails, and telecom/datacom isolated bias supply applications requiring stable component supply, full documentation, and pre-validated performance.

Supply support for MAXREFDES48# 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

Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in analog, mixed-signal, and power-management solutions for industrial, automotive, and communications markets.

The MAXREFDES reference design series targets rapid prototyping and system-level validation of Maxim's power controllers - specifically enabling fast evaluation of active-clamp forward converters, isolation integrity, and industrial-grade reliability.

FAQ

What is the primary function of the MAXREFDES48# reference design?

The MAXREFDES48# reference design implements a fully tested isolated 24V-to-12V 40W forward-converter power supply using the MAX17599 active-clamp PWM controller. Its primary function is to provide engineers with a validated, documentation-rich platform for evaluating functional insulation, active-clamp reset benefits, and industrial input-range operation - not as a standalone IC or component, but as a complete system board.

Does the MAXREFDES48# include the MAX17599 controller, and is it populated on the board?

Yes, the MAXREFDES48# reference design includes the MAX17599 low-I_Q active-clamp PWM controller fully populated and operational on the board. The MAXREFDES48# relies on this IC for current-mode control, soft-start, hiccup overcurrent protection, and active-clamp timing - all verified in the delivered hardware configuration.

What transformer type is used in the MAXREFDES48#, and how does it differ from MAXREFDES41#?

The MAXREFDES48# uses an EFD20 core ferrite transformer. In contrast, MAXREFDES41# uses a planar transformer - a physical and layout-level distinction that affects height, thermal profile, and manufacturability. The two designs share functional goals but are not interchangeable due to differing magnetics, PCB stack-up, and layout constraints.

Can the switching frequency of the MAXREFDES48# be adjusted, and how is EMI managed?

Yes, the MAXREFDES48# operates at a nominal 250kHz but supports programmable frequency dithering via external components to enable low-EMI spread-spectrum operation. This feature directly reduces peak radiated emissions without requiring additional filtering, making the MAXREFDES48# suitable for EMI-sensitive industrial and telecom applications.

What protection features are implemented in the MAXREFDES48# design?

The MAXREFDES48# implements input undervoltage lockout (EN/UVLO set to 16.5V), overvoltage input protection (OVI set to 37.0V), hiccup-mode overcurrent protection, thermal shutdown, and soft-stop for controlled clamp capacitor discharge. These protections are integral to the MAX17599 IC and validated in the MAXREFDES48# board-level implementation.