Analog Devices Inc./Maxim Integrated MAX17681AEVKITC#

Overview

MAX17681AEVKITC# from Maxim Integrated is an evaluation kit for the MAX17681A high-voltage iso-buck DC-DC converter IC, enabling rapid prototyping of isolated 5W power supplies with primary-side regulation and robust secondary-side overcurrent protection. It supports 4.5V–42V input, delivers up to 24V/100mA output via a 1:2.4 transformer, and targets industrial isolation applications requiring no optocoupler.

For engineers reviewing the MAX17681AEVKITC# datasheet, MAX17681AEVKITC# pinout, MAX17681AEVKITC# application, or MAX17681AEVKITC# equivalent, this kit provides validated reference design, thermal performance data, hiccup-mode recovery waveforms, and layout guidance for iso-buck topologies in PLC I/O modules, smart meters, and medical floating supplies.

Technical Context

The MAX17681AEVKITC# implements the MAX17681A controller in a fully assembled, tested PCB layout featuring a 10-pin TDFN (3mm × 2mm) IC, 1:2.4 turns-ratio transformer (T1), synchronous MOSFETs, all-ceramic output filtering (C1–C8), and adjustable EN/UVLO (R1), soft-start (C4), and feedback (R2/R3) networks. It demonstrates peak-current-mode control with 200kHz switching frequency and programmable hiccup timeout (32,768 cycles).

This kit validates the MAX17681A's dual overcurrent protection: primary-side peak/sink/runaway limits (1.65A/1.25A/1.7A typ) and MAX17681A-exclusive 16-consecutive-negative-current-limit detection for reliable secondary short-circuit response. It also confirms ±1.7% FB accuracy, 0.9μA shutdown current, and -40°C to +125°C operation with thermal shutdown at 165°C.

Key Specifications

Availability

MAX17681AEVKITC# is available at Aetrix Electronics and suitable for PLC I/O module development, smart meter power architecture validation, and isolated medical equipment supply qualification requiring stable component supply and pre-validated thermal/mechanical performance.

Supply support for MAX17681AEVKITC# 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 systems.

The MAX17681A product line delivers high-efficiency, isolated DC-DC conversion using primary-side regulation - specifically engineered to replace optocoupler-based flyback designs in space-constrained, high-reliability industrial power supplies.

FAQ

What is the purpose of the MAX17681AEVKITC# evaluation kit?

The MAX17681AEVKITC# is a fully assembled evaluation platform for the MAX17681A iso-buck DC-DC controller. It demonstrates isolated 5W power delivery (e.g., 24V/100mA) using primary-side regulation, validates secondary-side overcurrent protection behavior, and provides reference layout, BOM, and test points for rapid integration into industrial designs. The MAX17681AEVKITC# includes all passive components, transformer T1 (1:2.4), and configured feedback network per Figure 9 of the MAX17681A datasheet.

Does the MAX17681AEVKITC# support both MAX17681 and MAX17681A devices?

No - the MAX17681AEVKITC# is specifically configured and validated for the MAX17681A, which adds robust secondary-side overcurrent protection not present in the MAX17681. While the PCB footprint accommodates the 10-pin TDFN package common to both, the kit's transformer selection, compensation network (C4 = 33nF), and default feedback resistors (R2 = 10kΩ, R3 = 4.75kΩ) are optimized for MAX17681A's hiccup logic and timing. Using MAX17681 may result in incomplete secondary fault response.

What input and output configurations does the MAX17681AEVKITC# demonstrate?

The MAX17681AEVKITC# demonstrates a 17V–32V input range delivering 24V at 100mA on the secondary side, achieved via a 1:2.4 transformer turns ratio and primary-side regulation set to ~9.8V (VPRI). Input capacitors include 10µF (C2) and 1µF (C1); output filtering uses 1µF (C3), 33nF (C5), 2.2µF (C7), and 680pF (C6). The MAX17681AEVKITC# also includes Zener-based overvoltage protection (Z1 + R4) for no-load conditions.

How is soft-start implemented on the MAX17681AEVKITC#?

The MAX17681AEVKITC# implements soft-start using a 33nF ceramic capacitor (C4) connected from the SS pin to GND, yielding a typical soft-start time of ~184ms (tSS = 5.55 × CSS in ns). This ramp controls the internal error amplifier reference to ensure monotonic VPRI rise, minimizing inrush current during startup. The SS pin is internally discharged when EN/UVLO is pulled low, ensuring controlled restart after disable - a behavior verified on the MAX17681AEVKITC# board.

Can the MAX17681AEVKITC# be used to evaluate thermal performance?

Yes - the MAX17681AEVKITC# incorporates the MAX17681A in its standard 10-pin TDFN package with exposed pad (EP) soldered to a large copper plane, matching JEDEC JESD51-7 four-layer thermal test conditions. Measured θJA = 67.3°C/W allows direct correlation with datasheet thermal derating curves. Thermal shutdown (165°C) and hysteresis (10°C) are observable via RESET pin behavior and LX waveform collapse during overload testing on the MAX17681AEVKITC#.