Analog Devices Inc./Maxim Integrated MAX17681EVKITF#

Overview

MAX17681EVKITF# from Maxim Integrated is an evaluation kit for the MAX17681/MAX17681A high-voltage iso-buck DC-DC converter IC, enabling rapid prototyping of isolated 5W power supplies. It supports 4.5V–42V input, delivers regulated primary-side output up to 24V/100mA (2.4W), features primary-side feedback without optocoupler, and implements peak-current-mode control with integrated 0.55Ω pMOS and 0.2Ω nMOS switches.

For engineers reviewing the MAX17681EVKITF# datasheet, MAX17681EVKITF# pinout, MAX17681EVKITF# application, or MAX17681EVKITF# equivalent, this kit provides validated reference design, transformer-coupled isolation, hiccup-mode overcurrent protection, thermal shutdown, and adjustable soft-start - all critical for evaluating industrial isolated power in PLC I/O modules, fieldbus interfaces, and smart meters.

Technical Context

The MAX17681EVKITF# implements the MAX17681A iso-buck topology using a 1:2.4 turns-ratio transformer (T1), primary-side regulation via FB pin, and synchronous switching at 200kHz (±13kHz). It leverages internal 5V LDO (VCC) to drive low-side MOSFET, supports programmable EN/UVLO threshold (1.218V typ), and uses SS pin with 3300pF capacitor for controlled soft-start ramp.

It validates key protection mechanisms: peak current limit (1.65A typ), runaway current limit (1.7A typ), sink current limit (1.25A typ), and secondary-side overcurrent detection (16 consecutive negative current events) unique to MAX17681A - enabling robust recovery after short-circuit on isolated output rails.

Key Specifications

Availability

MAX17681EVKITF# is available at Aetrix Electronics and suitable for industrial automation, smart metering, and isolated fieldbus interface development requiring stable component supply, pre-validated transformer coupling, and production-ready layout guidance.

Supply support for MAX17681EVKITF# 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 MAX17681/MAX17681A product line targets isolated DC-DC conversion in space-constrained, high-reliability systems - eliminating optocouplers while maintaining ±1.7% feedback accuracy and -40°C to +125°C operation.

FAQ

What is the purpose of the MAX17681EVKITF# evaluation kit?

The MAX17681EVKITF# is a fully assembled and tested evaluation board designed to demonstrate and validate the performance of the MAX17681A iso-buck DC-DC converter IC. It implements a complete isolated 24V/100mA power supply using primary-side regulation, a 1:2.4 transformer, and all necessary passive components - allowing engineers to verify efficiency, transient response, hiccup-mode behavior, and thermal performance before custom design.

Does the MAX17681EVKITF# support both MAX17681 and MAX17681A ICs?

No - the MAX17681EVKITF# is specifically configured and validated for the MAX17681A, which includes enhanced secondary-side overcurrent protection logic. While the board's schematic is compatible with the MAX17681, key features like 16-cycle negative current detection and active primary capacitor discharge during hiccup mode are only functional when the MAX17681A is installed.

What input voltage range does the MAX17681EVKITF# operate within?

The MAX17681EVKITF# application circuit is optimized for 17V to 32V DC input, as shown in the reference schematic. This falls within the full 4.5V–42V operating range of the underlying MAX17681A IC, but board-level component ratings (e.g., C1, C2, D1) are selected for reliable operation in the 17–32V window.

How is isolation achieved on the MAX17681EVKITF#?

Isolation on the MAX17681EVKITF# is achieved through transformer coupling: the MAX17681A regulates voltage on the primary side (VPRI), and a 1:2.4 turns-ratio transformer (T1) steps it up to 24V on the secondary side. No optocoupler or auxiliary winding is required - primary-side feedback eliminates signal isolation barriers while maintaining >2.5kVRMS reinforced isolation per transformer specification.

Can the MAX17681EVKITF# be used to evaluate different output voltages?

Yes - output voltage is set by transformer turns ratio and primary-side feedback divider. The MAX17681EVKITF# uses R1=105kΩ and R2=10kΩ to set VPRI = 9.8V, yielding 24V at secondary with 1:2.4 ratio. To evaluate other outputs, users can replace T1 with alternate turns ratios and adjust R1/R2 per the formula R1 = R2 × (VPRI/0.9 − 1), where VPRI = VOUT × (NPRI/NSEC).