Analog Devices Inc./Maxim Integrated MAX17681AEVKITA#

Overview

The MAX17681AEVKITA# from Maxim Integrated is an evaluation kit for the MAX17681A high-voltage iso-buck DC-DC converter, enabling rapid validation of isolated 5W power designs using primary-side regulation, peak-current-mode control, and integrated 0.55Ω pMOS / 0.2Ω nMOS switches across 4.5V–42V input range.

For engineers reviewing the MAX17681AEVKITA# datasheet, MAX17681AEVKITA# pinout, MAX17681AEVKITA# application, or MAX17681AEVKITA# equivalent, this board supports full characterization of hiccup-mode secondary overcurrent protection, soft-start timing, RESET assertion behavior, thermal shutdown response, and transformer-coupled output regulation without optocouplers.

Technical Context

The MAX17681AEVKITA# implements the MAX17681A IC in a fixed 24V_IN → 24V_OUT (100mA) reference design with 1:2.4 turns-ratio transformer T1, 33nF soft-start capacitor, 105kΩ feedback divider, and all-ceramic output filtering. It validates the IC's primary-side feedback architecture, where VPRI is regulated to 0.96×VIN and scaled via transformer to deliver isolated output.

This kit demonstrates the MAX17681A's enhanced hiccup mode-triggered by 16 consecutive negative current limit events-to actively discharge CPRI and enable smooth recovery after secondary short-circuit faults, a capability absent in the base MAX17681. It also confirms operation across –40°C to +125°C with ±1.7% FB accuracy and 200kHz switching.

Key Specifications

Availability

The MAX17681AEVKITA# is available at Aetrix Electronics and suitable for PLC I/O modules, isolated fieldbus interfaces, smart meter auxiliary supplies, and floating power generation requiring stable component supply, full documentation access, and pre-validated thermal and protection behavior.

Supply support for MAX17681AEVKITA# 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 applications.

The MAX17681A product line delivers isolated DC-DC conversion using iso-buck topology, targeting space-constrained systems needing robust secondary fault handling, wide input range, and elimination of optocouplers in safety-isolated power rails.

FAQ

What is the MAX17681AEVKITA# used for?

The MAX17681AEVKITA# is an evaluation kit designed to validate the MAX17681A iso-buck DC-DC controller in real-world isolated power applications. It enables engineers to verify primary-side voltage regulation, secondary overcurrent protection recovery, soft-start timing, RESET signal behavior, thermal shutdown response, and transformer-coupled efficiency up to 5W - all without requiring custom PCB design or optocoupler integration. The MAX17681AEVKITA# uses the exact MAX17681A IC in a proven layout.

Does the MAX17681AEVKITA# support both MAX17681 and MAX17681A ICs?

No - the MAX17681AEVKITA# is specifically configured and tested for the MAX17681A, which includes enhanced secondary-side overcurrent protection logic not present in the MAX17681. While the board's footprint accommodates the same 10-pin TDFN package, key features like 16-cycle hiccup triggering, active CPRI discharge during fault recovery, and improved VFB-OK thresholds are only functional when the MAX17681A IC is installed. Using a MAX17681 on this board will not demonstrate robust secondary short-circuit recovery.

What transformer is used on the MAX17681AEVKITA# board?

The MAX17681AEVKITA# uses transformer T1 with a 1:2.4 turns ratio (NPRI:NSEC), optimized to generate 24V/100mA from a regulated primary-side voltage (VPRI) of approximately 9.8V. This ratio is explicitly specified in the application circuit diagram and supports the 5W output target while maintaining stable regulation under load transients. The transformer meets reinforced insulation requirements for medical and industrial isolation standards.

Can the MAX17681AEVKITA# be modified for different output voltages?

Yes - the MAX17681AEVKITA# supports output voltage adjustment via the feedback resistor divider (R1/R2) and transformer turns ratio. The onboard R1 = 105kΩ and R2 = 10kΩ set VPRI ≈ 9.8V; changing R1 recalculates VPRI using VFB_REG = 0.9V, and selecting a different transformer (e.g., 1:1.5 or 1:3.0) scales the isolated output accordingly. All ceramic capacitors and MOSFETs remain valid across the 0.9V–0.96×VIN VPRI range supported by the MAX17681A IC on the MAX17681AEVKITA#.

Does the MAX17681AEVKITA# include thermal measurement points?

Yes - the MAX17681AEVKITA# places the MAX17681A IC in a 3mm × 2mm TDFN package with exposed pad (EP) soldered directly to a large internal ground plane, matching the thermal layout guidelines in the datasheet. Test points adjacent to the EP and LX pins allow direct junction temperature monitoring during overload or hiccup-mode testing. Thermal shutdown is confirmed to activate at +165°C with 10°C hysteresis, as specified for the MAX17681A IC used on the MAX17681AEVKITA#.