Analog Devices Inc./Maxim Integrated MAXREFDES115A#

Overview

MAXREFDES115A# from Maxim Integrated is an isolated 24V-to-5V, 20W (4A) industrial DC-DC reference design board built around the MAX17599 active-clamp current-mode PWM controller. It delivers peak efficiency of 91.5% at 24V input, features functional insulation, through-hole mounting pins, and operates at 250kHz with optional frequency dithering for EMI reduction.

For engineers reviewing the MAXREFDES115A# datasheet, MAXREFDES115A# pinout, MAXREFDES115A# application, or MAXREFDES115A# equivalent, key selection criteria include isolation compliance, 5V/4A output stability under transient load steps (e.g., 5mA ↔ 1600mA), input UVLO/OVI thresholds (16.5V/37.0V), compact 20mm × 55mm footprint, and transformer-qualified compatibility with Wurth 750315945.

Technical Context

The MAXREFDES115A# implements a flyback-derived active-clamp forward converter topology using the MAX17599 controller, which integrates AUXDRV and NDRV drivers for zero-voltage switching of the clamp switch and main FET. Its control loop employs a TLV431B shunt regulator and 3000V optocoupler for isolated feedback.

It supports programmable soft-start, hiccup-mode overcurrent protection, thermal shutdown, and input undervoltage lockout (EN/UVLO) set to 16.5V with overvoltage protection (OVI) at 37.0V. The design achieves ±0.25V output regulation across 0–4A load and exhibits 240mV output transient spike during 2.4A ↔ 4A load steps at 24V input.

Key Specifications

Availability

MAXREFDES115A# is available at Aetrix Electronics and suitable for PLCs, industrial process control systems, and telecom/datacom power supplies requiring stable component supply, rapid prototyping integration, and qualified transformer interoperability.

Supply support for MAXREFDES115A# 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 series delivers fully tested, documented, and purchasable reference designs focused on accelerating robust isolated power supply development for harsh industrial environments.

FAQ

What is the input voltage range supported by the MAXREFDES115A#?

The MAXREFDES115A# supports a nominal 24V input with validated operation from 16.5V to 37.0V. This range is enforced by the MAX17599's EN/UVLO (set to 16.5V turn-on threshold) and OVI (37.0V shutdown threshold) circuits, ensuring reliable startup and overvoltage protection. The MAXREFDES115A# has been tested across this full range per its lab measurement reports.

What output regulation accuracy does the MAXREFDES115A# achieve?

The MAXREFDES115A# maintains 5V ±0.25V output voltage across its full 0–4A load range when supplied with 24V input. This regulation is achieved via an isolated feedback loop using a TLV431B shunt regulator and 3000V optocoupler, as confirmed in Quick Start verification procedure step 10 and Figure 4 ripple measurements.

Which transformer is qualified for use with the MAXREFDES115A#?

The MAXREFDES115A# is qualified with the Wurth Elektronik transformer part number 750315945. This specific transformer is explicitly listed in the system board documentation for MAXREFDES115A#, enabling simplified selection and guaranteed performance without redesign. Other variants (e.g., MAXREFDES115B#/C#) use Sumida and Hanrun transformers respectively.

Does the MAXREFDES115A# support EMI reduction techniques?

Yes, the MAXREFDES115A# supports low-EMI spread-spectrum operation via programmable frequency dithering, enabled through the MAX17599 controller. This feature reduces peak radiated emissions and eases compliance with industrial EMI standards, as noted in the "Introduction" section describing its utility for EMI-sensitive applications.

How is thermal protection implemented on the MAXREFDES115A#?

The MAXREFDES115A# incorporates overtemperature fault protection via the MAX17599's integrated thermal shutdown circuit. When die temperature exceeds the safe operating limit, the controller halts switching to prevent damage-ensuring robust operation in adverse industrial environments, as stated in the "Detailed Circuit Description" and "Features" sections.