MAX25256

RECOMMENDED FOR NEW DESIGNS

Automotive, 36V H-Bridge Transformer Driver for Isolated Supplies

Small, Simple Isolated Supply for EV/HEV Applications to Bias Gate Drives

Data Sheet (Rev. 0) Product Selection Table

Part Models: 2
1ku List Price: Starting From $1.00

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Overview

Simple Flexible Design
- 8V to 36V Supply Range
- Up to 90% Efficiency
- Provides Up to 10W to the Transformer
- Undervoltage Lockout (UVLO)
- 2.5V to 5V Compatible Logic Interface
- Internal or External Clock Source
- Adjustable Overcurrent Threshold
Integrated System Protection
- Fault Detection and Indication
- Overcurrent Limiting
- Overtemperature Protection
Saves Space on Board
- Small 10-Pin TDFN Package (3mm x 3mm)
- AEC-Q100 Qualified

The MAX25256 H-bridge transformer driver provides a simple solution for making isolated power supplies up to 10W. The device drives a transformer’s primary coil with up to 300mA of current from a wide 8V to 36V direct current (DC) supply. The transformer’s secondary-to-primary winding ratio defines the output voltage, allowing selection of virtually any isolated output voltage.

The device features adjustable current limiting, allowing indirect limiting of secondary-side load currents. The current limit of the MAX25256 is set by an external resistor. A active-low FAULT output asserts when the device detects an overtemperature or overcurrent condition. In addition, the device features a low-power mode to reduce the overall supply current to 0.65mA (typ) when the driver is not in use.

The device can be operated using the internal oscillator or driven by an external clock to synchronize multiple MAX25256 devices and precisely set the switching frequency. Internal circuitry guarantees a fixed 50% duty cycle to prevent DC flow through the transformer, regardless of which clock source is used.

The device is available in a small 10-pin (3mm x 3mm) TDFN package and is specified over the -40°C to +125°C automotive temperature range.

Applications

Dual-Battery Systems
Isolated Gate Driver Supplies
Isolated Supplies for controller area network (CAN), serial peripheral interface (SPI), I²C, etc.
Isolated Supplies for Motor Control

Part Models: 2
1ku List Price: Starting From $1.00

Documentation

Data Sheet 1

MAX25256: Automotive, 36V H-Bridge Transformer Driver for Isolated Supplies Data Sheet (Rev.0) 09/23/2021

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
MAX25256ATBA/V+	LFCSP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
MAX25256ATBA/V+T	LFCSP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Apr 27, 2024 - 2400 ASSEMBLY
		pcn_2400
MAX25256ATBA/V+	PRODUCTION
MAX25256ATBA/V+T	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Evaluation Kits

Evaluation Kit for the MAX25256

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Features and Benefits

8V to 36V Input Supply Range
Up to 90% Efficiency
Full-Wave Rectified Output
Configurable for a Voltage Doubler, Bipolar Half-Wave Rectifier, and Push-Pull Rectifier Outputs
Internal or External Clock Operation Option
Proven PCB Layout
Fully Assembled and Tested

Product Details

The MAX25256 evaluation kit (EV kit) is a fully assembled and tested PCB that contains the MAX25256 10W isolated H-bridge DC-DC converter. The EV kit operates from an 8V to 36V DC power source and the on-board 1:1 turns-ratio transformer from HALO sets the output voltage range from 6.8V to 34.8V with a 215mA current limit.

The EV kit provides greater than 90% overall efficiency at +24V between 2.2W and up to 8.3W output power using an H-bridge DC-DC converter topology. Input-ripple current and radiated noise are minimized by the inherent balanced nature of the design with no interruption in the input current. Undervoltage lockout (UVLO), adjustable current limit, and thermal shutdown provide for a robust 10W isolated supply. The surface-mount transformer provides galvanic isolation with the output powered from a full-wave rectifier circuit, reducing the output-voltage ripple.

The EV kit circuit is configured as a full-wave rectifier, with an output voltage that follows the input voltage but is configurable for other topologies including a voltage doubler, bipolar outputs, half-wave rectification, and a push-pull rectifier.

The device is available in a 10-pin (3mm x 3mm) TDFN package with an exposed pad.