Analog Devices Inc./Maxim Integrated MAXREFDES114A#

Overview

MAXREFDES114A# from Maxim Integrated is an isolated 24V-to-5V, 10W (2A) industrial reference design board implementing an active-clamp forward converter topology with the MAX17599 PWM controller. It delivers peak efficiency of 92% at 24V input, features functional insulation, 330kHz switching, and compact 20mm × 40mm PCB layout optimized for PLC and sensor power rails.

For engineers reviewing the MAXREFDES114A# datasheet, MAXREFDES114A# pinout, MAXREFDES114A# application, or MAXREFDES114A# equivalent, key selection criteria include input voltage range (17–36V), output regulation accuracy (5V ±0.25V), hiccup-mode overcurrent protection, soft-start/soft-stop control, and transformer vendor-specific variants (e.g., Wurth 750316112r01).

Technical Context

The MAXREFDES114A# implements a wide-input (17–36V), isolated forward-converter architecture using the MAX17599 active-clamp current-mode PWM controller. It employs zero-voltage switching via programmable dead time between NDRV and AUXDRV outputs, and uses a TLV431B + optocoupler feedback loop with 3000V isolation for precise 5V regulation.

Protection features include EN/UVLO (16.5V turn-on), OVI (37.0V shutdown), hiccup-mode overcurrent, thermal shutdown, and soft-stop clamp-capacitor discharge. Input-to-output creepage/clearance meets industrial safety requirements with through-hole pins spaced 15.24mm (power-to-ground) and 27.94mm (input-to-output).

Key Specifications

Availability

MAXREFDES114A# is available at Aetrix Electronics and suitable for programmable logic controllers (PLCs), industrial process control systems, and isolated sensor interface modules requiring stable component supply and rapid prototyping support.

Supply support for MAXREFDES114A# 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 high-performance analog, mixed-signal, and power-management ICs for industrial, automotive, and communications applications.

The MAXREFDES reference design series targets robust, pre-validated power architectures for harsh industrial environments-specifically enabling fast deployment of isolated DC-DC conversion in PLCs, distributed I/O, and field instrumentation.

FAQ

What is the input voltage range supported by the MAXREFDES114A#?

The MAXREFDES114A# operates across a 17V to 36V DC input range, with EN/UVLO set to 16.5V turn-on and OVI protection triggered at 37.0V. This ensures reliable startup and fault shutdown under industrial 24V rail variations, including transient overvoltage and brownout conditions. The MAXREFDES114A# maintains regulation and efficiency across this full range.

Does the MAXREFDES114A# provide galvanic isolation, and what is its isolation rating?

Yes, the MAXREFDES114A# provides functional galvanic isolation between input and output using a discrete transformer (Wurth 750316112r01) and 3000V-rated optocoupler feedback. It achieves physical creepage and clearance compliant with industrial safety standards, though it is not certified for reinforced or basic insulation per IEC 60950/62368. The MAXREFDES114A# isolates ground domains to suppress noise and eliminate ground loops in PLC backplanes.

What protection features are implemented on the MAXREFDES114A#?

The MAXREFDES114A# integrates multiple hardware-level protections: input undervoltage lockout (EN/UVLO), input overvoltage shutdown (OVI), hiccup-mode overcurrent limiting, thermal shutdown, and soft-stop clamp-capacitor discharge. These functions are implemented directly by the MAX17599 controller and associated passive network, ensuring autonomous fault response without external supervision. The MAXREFDES114A# sustains safe operation during line transients and load faults.

Can the switching frequency of the MAXREFDES114A# be adjusted?

The MAXREFDES114A# defaults to 330kHz operation but supports frequency dithering via the MAX17599's FREQ pin to reduce EMI peaks. Dithering is enabled by connecting an external resistor and capacitor to configure spread-spectrum modulation depth and rate. No reprogramming or firmware update is required-the MAXREFDES114A# frequency behavior is fully analog and hardware-configurable per application EMI requirements.

What transformer is used on the MAXREFDES114A# board?

The MAXREFDES114A# uses the Wurth Elektronik transformer model 750316112r01, selected for optimal coupling, leakage inductance, and flux swing in the active-clamp forward topology. This transformer is pre-qualified for the design and ensures consistent performance across production units. Alternative versions (MAXREFDES114B#/C#/D#) use Sumida, Hanrun, or Halo transformers-but only the MAXREFDES114A# ships with the Wurth unit.