Analog Devices Inc./Maxim Integrated MAXREFDES116D#

Overview

MAXREFDES116D# from Maxim Integrated is an isolated 24V-to-5V, 40W (8A) industrial DC-DC reference design based on the MAX17599 active-clamp forward controller. It implements functional insulation, operates across 17–36V input, delivers peak efficiency of 91.5% at 24V input, and fits on a compact 20mm × 70mm board with through-hole pins for rapid prototyping.

For engineers reviewing the MAXREFDES116D# datasheet, MAXREFDES116D# pinout, MAXREFDES116D# application, or MAXREFDES116D# equivalent, this reference design supports fast validation of isolated 5V rail generation in PLCs, industrial sensors, telecom power supplies, and embedded systems requiring robust EMI performance, hiccup-mode OCP, and programmable frequency dithering.

Technical Context

The MAXREFDES116D# implements an active-clamp forward converter topology using the MAX17599 PWM controller, enabling zero-voltage switching via programmable dead-time between main and auxiliary drivers. It features transformer reset without dissipative snubbers, reducing voltage stress on MOSFETs and allowing larger flux swing for smaller magnetics.

Control functions include EN/UVLO (16.5V start), OVI (37.0V shutdown), soft-start, soft-stop clamp capacitor discharge, negative current limiting, and thermal shutdown. Switching frequency is fixed at 350kHz with optional spread-spectrum dithering for EMI reduction.

Key Specifications

Availability

MAXREFDES116D# is available at Aetrix Electronics and suitable for programmable logic controllers (PLCs), industrial process control systems, and telecom/datacom power supplies requiring stable component supply, rapid prototyping support, and verified EMI performance.

Supply support for MAXREFDES116D# 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) designs precision analog, mixed-signal, and power-management ICs for industrial, automotive, and communications applications.

The MAXREFDES reference design series targets validated, production-ready power architectures - specifically isolated DC-DC converters for harsh industrial environments where reliability, compactness, and regulatory-compliant insulation are critical.

FAQ

What is the input voltage range supported by the MAXREFDES116D#?

The MAXREFDES116D# supports an input voltage range of 17V to 36V DC, with undervoltage lockout set to 16.5V and overvoltage protection triggered at 37.0V. This ensures reliable operation across standard 24V industrial bus variations, including transient dips and surges. The MAXREFDES116D# maintains regulation and protection functionality throughout this range.

Does the MAXREFDES116D# provide galvanic isolation, and what is its isolation rating?

The MAXREFDES116D# provides functional insulation via an off-the-shelf transformer and optocoupler-based feedback, meeting basic isolation requirements for industrial signal/power separation. It is not rated for reinforced or safety isolation (e.g., UL 60950 or IEC 62368). The MAXREFDES116D# is intended for applications where functional separation-not safety-critical barrier-between input and output is required.

What protection features are implemented in the MAXREFDES116D# design?

The MAXREFDES116D# integrates input UVLO (16.5V), OVI (37.0V), hiccup-mode overcurrent protection, soft-start, soft-stop clamp discharge, negative current limiting, and thermal shutdown. These protections are implemented via the MAX17599 controller and discrete components - ensuring robust fault recovery and safe restart behavior under line/load transients or thermal overload. The MAXREFDES116D# sustains operation without latch-up or damage during repeated faults.

Can the switching frequency of the MAXREFDES116D# be adjusted, and how is EMI managed?

The MAXREFDES116D# operates at a nominal 350kHz, with optional frequency-dithering enabled via external resistor programming to achieve low-EMI spread-spectrum operation. This reduces peak radiated emissions without altering layout or filtering. The MAXREFDES116D# was tested per CISPR 22/32 guidelines, and its dithering capability allows tuning to meet specific system-level EMC requirements.

Is the MAXREFDES116D# suitable for use in PLC power supply designs?

Yes - the MAXREFDES116D# is explicitly validated for programmable logic controller (PLC) applications, delivering a stable 5V/8A isolated rail with high efficiency (91.5%), wide input range (17–36V), and robust protection against industrial transients. Its compact size, through-hole mounting, and pre-tested performance make the MAXREFDES116D# ideal for PLC backplane or module-level power distribution.