MAX256

3W Primary-Side Transformer H-Bridge Driver for Isolated Supplies

Buy Now

Production

Top

New Content (1)

Webcast

Signal Chain Power: New Integrated Hardware and Software Tool for Power Design, Development and Evaluation

Overview

Features and Benefits
Product Details

Features and Benefits

Simple, Flexible Design Provides Up to 3W to the Transformer in Isolated Power Supplies
- Single Supply +5V or +3.3V Operation
- Internal Resistor-Programmable Oscillator Mode
- External Clock Mode with Watchdog
- Disable Mode
Integrated System Protection
- Undervoltage Lockout
- Thermal Shutdown
Saves Space on Board
- 8-Pin Thermally-Enhanced SO Package

Product Details

The MAX256 is an integrated primary-side controller and H-bridge driver for isolated power-supply circuits. The device contains an on-board oscillator, protection circuitry and internal FET drivers to provide up to 3W of power to the primary winding of a transformer. The MAX256 can be operated using the internal programmable oscillator or can be driven by an external clock for improved EMI performance. Regardless of the clock source being used, an internal flip-flop stage guarantees a fixed 50% duty cycle to prevent DC current flow in the transformer.

The MAX256 operates from a single-supply voltage of +5V or +3.3V, and includes undervoltage lockout for controlled startup. The device prevents cross-conduction of the H-bridge MOSFETs by implementing break-before-make switching. Thermal shutdown circuitry provides additional protection against damage due to overtemperature conditions.

The MAX256 is available in the 8-pin thermally-enhanced SO package. The device is specified for the automotive (-40°C to +125°C) temperature range.

Applications

Industrial Process Control
Isolated Communications Links
Isolated Power Supplies
Medical Equipment
Telecommunications

Product Categories

Power Monitor, Control, and Protection
- Transformer Drivers

Comparable Parts Click to see all in Parametric Search

Product Lifecycle Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (2)

MAX256EVKIT

MAX256 Evaluation Kit

MAXSANTAFEEVSYS

Evaluation Kit for the MAXREFDES5 4-Channel Analog Front End

MAX256EVKIT

View Detailed Evaluation Kit Information

The MAX256 evaluation kit (EV kit) is a fully assembled and tested PCB that contains a 3W isolated H-bridge DC-DC converter. The circuit is configured for unregulated output voltages of approximately +5V and -5V (with respect to an isolated ground). Output current is up to 600mA from either output, or 300mA from each of the two outputs. Input power for the circuit is provided from a +5VDC source, or operates at any input voltage down to +3V with a corresponding reduction in the output voltages.

The EV kit provides greater than 85% overall efficiency at +5V between 250mW and 2W 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) and thermal shutdown provide for a robust 3W isolated supply. The surface-mount transformer provides up to 1500V_RMS galvanic isolation with each output powered from a center-tapped full-wave rectifier circuit to reduce output voltage ripple.

Operation at 400kHz allows the use of ceramic output capacitors and a small transformer.

Applications

Industrial Process Control
Isolated Communications Links
Isolated Power Supplies
Medical Equipment
Telecommunications

Features & Benefits

+3V to +5VDC Input Range
Isolated Outputs
- +VOUT: +5V Provides Up to 300mA
- -VOUT: -5V Provides Up to 300mA
87% Overall Efficiency at +5V Input and 200mA Load
Center-Tapped, Full-Wave Rectifier Output
400kHz Switching Frequency
2.7V Undervoltage Lockout (UVLO)
Designed for 1500V_RMS Isolation
Low-Cost, Integrated-FET H-Bridge Design
Fully Assembled and Tested

MAXSANTAFEEVSYS

View Detailed Evaluation Kit Information

The MAXSANTAFEEVSYS kit allows users to quickly demonstrate and evaluate the functionality of the MAXREFDES5 4-channel 16-bit, isolated analog front end (AFE) reference design without the need for a bench power supply, signal generator equipment, or Xilinx development kit. The reference design board connects to a PC through an included USB-to-SPI adapter that provides both power and data communication to the board. To test the AFE reference design, a USB-powered signal generator board utilizing one of Maxim’s digital-to-analog converters (DAC) is also included. A Windows^®-based graphical user interface (GUI) communicates with the boards for generating various analog signal test patterns and simplified access to AFE measurement data.

MAXSANTAFEEVSYS User Manual is available for download.

The MAXREFDES5 reference design is a 4-channel analog front end (AFE) that accepts -10V to +10V, 0V to 10V, and 4–20mA current loop signals. The design integrates a 16-bit ADC with multirange input programmability (MAX1301) plus low-noise, high-impedance analog buffers (MAX9632) on two of the input channels and an ultra-high precision 4.096V voltage reference (MAX6126) to achieve maximum performance from the 16-bit system. A 600V_RMS digital isolator (MAX14850) and 3W transformer driver (MAX256) provide the necessary isolated data and power connections to the host system. LDO regulators (MAX1659) provide regulated +12V, -12V, and 5V power rails to the analog front end.

EV Kit Contents

MAXREFDES5 4-Channel AFE Board
USB2PMB1 USB to Pmod^™ Type 2A Adapter Board
MAX5216DACLITE Signal Generator Board
Two (2) Wires with Hook Clips (1 Red and 1 Black)
Two (2) USB Type A Male to USB Type B Mini Cables
USB Flash Drive with Documentation, GUI Applications, and USB Drivers

Applications

Industrial Data Acquisition
Programmable Automation Controllers (PAC)
Programmable Logic Controllers (PLC)
Proportional-Integral-Derivative (PID) Controllers

Features & Benefits

Self-Contained Easy Evaluation Kit for MAXREFDES5
Optimized AFE with Common Analog Input Ranges
Small Form Factor Test Platform
All Relevant Reference Design Files Included

Resources

UG-5897: MAXSANTAFEEVSYS User Manual

PDF

484.00K

Documentation & Resources

Data Sheet

MAX256: 3W Primary-Side Transformer H-Bridge Driver for Isolated Supplies Data Sheet (Rev. 2)
4/23/2015
PDF

User Guide

UG-5651: Campbell (MAXREFDES4#) ZedBoard Quick Start Guide
5/20/2013
PDF
UG-5630: Fresno (MAXREFDES11#) ZedBoard Quick Start Guide
4/25/2013
PDF
UG-5639: Santa Fe (MAXREFDES5#) ZedBoard Quick Start Guide
4/22/2013
PDF
UG-5578: Santa Fe (MAXREFDES5#) Nexys 3 Quick Start Guide
2/4/2013
PDF
UG-5579: Campbell (MAXREFDES4#) Nexys 3 Quick Start Guide
2/4/2013
PDF

Webcast

Design Note

Isolated Power Using Capacitors
12/22/2010

Reference Designs (5)

Santa Fe (MAXREFDES5)

16-Bit High Accuracy Multi-Input Isolated Analog Front End (AFE)

MAXREFDES11 (Fresno)

16-Bit High-Accuracy 0 to 10V Input Isolated Analog Front End (AFE)

MAXREFDES4 (Campbell)

16-Bit High-Accuracy 4-20mA Input Isolated Analog Front End (AFE)

Lakewood (MAXREFDES7)

3.3V Input, ±12V (±15V) Output Isolated Power Supply

MAXREFDES8 (Riverside)

3.3V Input, 12V (15V) Output Isolated Power Supply

Santa Fe (MAXREFDES5)

16-Bit High Accuracy Multi-Input Isolated Analog Front End (AFE)

Santa Fe (MAXREFDES5)

16-Bit High Accuracy Multi-Input Isolated Analog Front End (AFE)

View Detailed Reference Design Information

Features & Benefits

High accuracy
±10V, 0 to 10V, and 4–20mA Inputs
Isolated power and data
Small printed circuit board (PCB) area
Device drivers
Example C source code
Pmod^™-compatible form factor

Parts Used

MAXREFDES4 (Campbell)

16-Bit High-Accuracy 4-20mA Input Isolated Analog Front End (AFE)

MAXREFDES4 (Campbell)

16-Bit High-Accuracy 4-20mA Input Isolated Analog Front End (AFE)

View Detailed Reference Design Information

Features & Benefits

High accuracy
4–20mA current loop input
0.2V to 4.096V input range
Isolated power and data
Small printed circuit board (PCB) area
Device drivers
Example C source code
Pmod^™-compatible form factor

Parts Used

Resources

MAXREFDES4 Design Files

ZIP

42.42 M

Lakewood (MAXREFDES7)

3.3V Input, ±12V (±15V) Output Isolated Power Supply

Lakewood (MAXREFDES7)

3.3V Input, ±12V (±15V) Output Isolated Power Supply

View Detailed Reference Design Information

Features & Benefits

Isolated power
±12V (±15V) outputs
Small printed circuit board (PCB) area
Pmod™-compatible form factor

Parts Used

Resources

MAXREFDES7 Design Files

ZIP

497.04 K

MAXREFDES8 (Riverside)

3.3V Input, 12V (15V) Output Isolated Power Supply

MAXREFDES8 (Riverside)

3.3V Input, 12V (15V) Output Isolated Power Supply

View Detailed Reference Design Information

Features & Benefits

Features

Isolated power
12V (15V) output
Small printed circuit board (PCB) area
Pmod^™-compatible form factor

Applications

Industrial sensors
Process control
Industrial automation
Medical

Parts Used

Resources

MAXREFDES8 Design Files

ZIP

485.99 K

Product Recommendations

MAX256 Companion Parts

Recommended Related Parts

MAX13085E, MAX13082E, MAX3072E, MAX3075E.

Design Resources

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 Number	Material Declaration	Reliability Data	Pin/Package Drawing	CAD Symbols, Footprints & 3D Models
MAX256ASA+	Material Declaration	Reliability Data	8-SOIC_N-150_MIL	Ultra Librarian SamacSys
MAX256ASA+T	Material Declaration	Reliability Data	8-SOIC_N-150_MIL	Ultra Librarian SamacSys
MAX256ASA/V+	Material Declaration	Reliability Data	8-SOIC_N-150_MIL	Ultra Librarian SamacSys
MAX256ASA/V+T	Material Declaration	Reliability Data	8-SOIC_N-150_MIL	Ultra Librarian SamacSys
Wafer Fabrication Data

PCN-PDN Information

Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.

Request Product/Process Change Notifications

Save to myAnalog

Support & Discussions

Contact ADI Technical Support »

Ask your question »

Contact ADI Technical Support »

Ask your question »

Sample & Buy

Ordering FAQs

See our Ordering FAQs for answers to questions about online orders, payment options and more.

Buy Now Pricing

(**) Displayed Buy Now Price and Price Range is based on small quantity orders.

List Pricing

(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

Lead Times

Please see the latest communication from our CCO regarding lead times.

Sampling

A Sample link will be shown above, next to the part, only for parts that are included in our sample program. Selecting the Sample button will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Price Table Help

Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.