Analog Devices Inc./Maxim Integrated MAX22256EVKIT#

Overview

MAX22256EVKIT# from Analog Devices is a fully assembled and tested evaluation kit for the MAX22256 family of 15W isolated H-bridge DC-DC converter ICs. It supports input voltages from 5V to 36V, delivers up to 1A output current with full-wave rectified unregulated output, and achieves >90% efficiency at 24V input across 2.2W–8.3W load range. The kit enables evaluation of PWM or LLC topologies and includes onboard LDO, galvanic isolation (1500VRMS), and configurable clocking (internal 450kHz or external).

For engineers reviewing the MAX22256EVKIT# datasheet, MAX22256EVKIT# pinout, MAX22256EVKIT# application, or MAX22256EVKIT# equivalent, this page provides verified hardware context, jumper-configurable operation modes (EN/CLKI), transformer topology options (full-wave, voltage doubler, half-wave), isolation layout compliance, and test-point–based measurement guidance for VOUT, VL, FAULT, and STx signals.

Technical Context

The MAX22256EVKIT# implements an isolated H-bridge DC-DC converter using the MAX22256A/B/C IC in a proven PCB layout with 1500VRMS isolation barrier (>300mil GND/GND_ISO spacing). It operates in default PWM mode with fixed 50% duty cycle enforced by internal flip-flop logic, regardless of clock source.

Hardware configuration includes jumper-selectable enable (J2) and clock source (J3), on-board Wurth transformer (750319919), and user-modifiable overcurrent limit via R5 (1.2kΩ sets 650mARMS threshold). Output rectification is full-wave by default but reconfigurable to voltage-doubler or half-wave topologies via secondary winding pads.

Key Specifications

Availability

MAX22256EVKIT# is available at Aetrix Electronics and suitable for power supply design validation, isolated DC-DC converter qualification, and automotive/industrial embedded system prototyping requiring stable component supply and traceable evaluation hardware.

Supply support for MAX22256EVKIT# 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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The MAX22256EVKIT# belongs to Analog Devices' isolated power evaluation platform family, designed specifically to accelerate development of compact, high-efficiency, safety-certifiable isolated DC-DC supplies for space-constrained applications.

FAQ

What does the MAX22256EVKIT# evaluate?

The MAX22256EVKIT# evaluates the MAX22256A, MAX22256B, and MAX22256C - monolithic isolated H-bridge DC-DC controller ICs with integrated MOSFETs, internal oscillator, and protection circuitry. It supports functional verification of PWM/LLC topologies, isolation performance, efficiency, and fault response (FAULT pin assertion, DS1 LED indication) under real-world load and input conditions.

How do I configure the MAX22256EVKIT# for internal vs. external clock operation?

Use jumper J3: short pins 1–2 (closed) to enable internal 450kHz oscillator; leave open to apply external clock to CLKI (TP4). When using external clock, the MAX22256EVKIT# divides the input frequency by two internally to guarantee 50% duty cycle on ST1/ST2 outputs - ensuring no DC bias on the transformer primary.

Can the MAX22256EVKIT# be used to evaluate LLC topology?

Yes, but requires hardware modification: install capacitors across R23/R24 pads and replace the onboard Wurth 750319919 transformer with a low-leakage LLC-optimized unit (e.g., Wurth 750319825). The MAX22256EVKIT# schematic and layout support this change, though efficiency and regulation performance depend on transformer selection and external compensation.

What is the purpose of the onboard LDO (U1) on the MAX22256EVKIT#?

The onboard MAX17651AZT+ LDO generates a regulated 5V supply (VL) for logic-level inputs/outputs (EN, CLKI), FAULT pin interface, and DS2 green LED. To use a different logic voltage, remove R1 and R10 and connect an external supply to TP12 (VL) and TP5/TP6 (GND), bypassing the LDO entirely.

How is overcurrent protection implemented on the MAX22256EVKIT#?

Overcurrent protection is set by resistor R5 (1.2kΩ), which configures the MAX22256's internal current-limit threshold to 650mARMS (typ). During overcurrent or overtemperature events, the FAULT pin asserts low and DS1 (red LED) illuminates. Threshold adjustment follows RLIM(kΩ) = 1200 / ILIM(mA) for 150–650mARMS range using 0805 resistors.