Analog Devices Inc./Maxim Integrated MAXREFDES112B#

Overview

MAXREFDES112B# from Maxim Integrated is an isolated 24V-to-12V, 10W flyback power supply reference design built around the MAX17596 peak-current-mode controller. It delivers 12V at up to 800mA (±5% output accuracy), achieves 88% peak efficiency at 24V input, and operates across a 17V–36V input range with programmable 500kHz switching frequency. The board features through-hole mounting pins and uses the Sumida 12387T070 transformer for industrial-grade isolation.

For engineers reviewing the MAXREFDES112B# datasheet, MAXREFDES112B# pinout, MAXREFDES112B# application, or MAXREFDES112B# equivalent, this reference design provides verified schematics, layout files, Gerber data, and lab-tested performance metrics-including load/line regulation, transient response (200mV spike at 480mA→800mA step), and EMI-optimized spread-spectrum operation-enabling rapid integration into PLC, process control, and telecom power systems.

Technical Context

The MAXREFDES112B# implements a wide-input (17V–36V) isolated flyback topology using the MAX17596 controller, which integrates a 1% accurate internal voltage reference and programmable soft-start via external capacitor. Its EN/UVLO and OVI protection circuits are resistor-configured to enable startup at 17V and shut down above 36V.

Feedback employs a TL431 shunt regulator and 3000V-isolation optocoupler for precise secondary-side regulation. The design supports hiccup-mode overcurrent protection, thermal shutdown, and frequency dithering to meet industrial EMI requirements without external filtering overhead.

Key Specifications

Availability

MAXREFDES112B# is available at Aetrix Electronics and suitable for industrial control and automation, programmable logic controller (PLC) auxiliary power, and telecom power supply applications requiring stable component supply, quick prototyping, and traceable sourcing of qualified reference designs.

Supply support for MAXREFDES112B# 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 solutions for industrial, automotive, and communications markets.

The MAXREFDES reference design series targets engineers needing pre-validated, production-ready power architectures-specifically isolated DC-DC converters optimized for reliability, compactness, and ease of transformer qualification in harsh environments.

FAQ

What is the primary function of the MAXREFDES112B#?

The MAXREFDES112B# is a fully assembled, tested reference design board that implements an isolated 24V-to-12V, 10W flyback power supply. It uses the MAX17596 controller and Sumida 12387T070 transformer to deliver regulated 12V output with functional insulation. The MAXREFDES112B# is intended for evaluation, prototyping, and direct integration into industrial systems requiring certified, repeatable power architecture.

Which transformer is used on the MAXREFDES112B# board?

The MAXREFDES112B# board is specifically configured with the Sumida 12387T070 transformer, as confirmed in Maxim's official system board documentation. This transformer is qualified for 3000V isolation, supports the 500kHz switching frequency, and enables the design's 88% peak efficiency and robust transient response. Other variants (e.g., MAXREFDES112A#/C#/D#) use different transformers, but the MAXREFDES112B# is uniquely matched to Sumida 12387T070.

Does the MAXREFDES112B# support input undervoltage lockout and overvoltage protection?

Yes, the MAXREFDES112B# implements both input undervoltage lockout (UVLO) and overvoltage input (OVI) protection via the MAX17596 controller. UVLO is set to 17V turn-on and 16.95V hysteresis, while OVI triggers shutdown at 36.6V. These thresholds are fixed by the onboard resistor network (R5 = 274kΩ, R6 = 11.3kΩ, R7 = 9.76kΩ) and ensure reliable operation during line sags and surges without external supervision circuitry.

What are the mechanical dimensions and mounting features of the MAXREFDES112B#?

The MAXREFDES112B# measures 20.3mm × 59.7mm (0.8in × 2.35in) and features through-hole pins on the bottom side for immediate mechanical attachment and signal/power routing. Pin spacing is 0.6in between power and ground, and 2in between input and output sides-enabling straightforward integration into host PCBs without custom adapters. No surface-mount assembly is required for basic deployment.

How does the MAXREFDES112B# achieve EMI compliance in industrial settings?

The MAXREFDES112B# incorporates programmable frequency dithering in the MAX17596 controller to enable low-EMI spread-spectrum operation. Combined with optimized layout, snubberless transformer selection (Sumida 12387T070), and inherent peak-current-mode stability, this reduces narrowband emissions without adding bulk filtering components. Lab measurements confirm clean transient behavior (200mV spike) and ripple (110mV_P-P) under full load-key for meeting CISPR 11 Class A limits in factory-floor deployments.