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MAX256

MAX256

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

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Overview

Description

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.

MAX256: Typical Operating Circuit MAX256: Typical Operating Circuit Enlarge+

Key Features

  • 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

Applications/Uses

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

Parametric Specs

Part NumberVIN
(V)		VIN
(V)		Driver Output Resistance
(Ω)		Max. IOUT
(A)		TopologyFreq.
(kHz)		ICC
(mA)		Package/PinsOper. Temp.
(°C)		Budgetary
Price
minmaxmaxmaxSee Notes
MAX256 35.511Full-Bridge10001
SOIC (N)/8
-40 to +125$3.34 @1k
See All Transformer Drivers (6)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Design Resources


MAX256EVKIT: MAX256 Evaluation Kit
MAXSANTAFEEVSYS: Evaluation Kit for the MAXREFDES5 4-Channel Analog Front End

Technical Documents

User Guide 5651 Campbell (MAXREFDES4#) ZedBoard Quick Start Guide
User Guide 5639 Santa Fe (MAXREFDES5#) ZedBoard Quick Start Guide
User Guide 5630 Fresno (MAXREFDES11#) ZedBoard Quick Start Guide
User Guide 5579 Campbell (MAXREFDES4#) Nexys 3 Quick Start Guide
User Guide 5578 Santa Fe (MAXREFDES5#) Nexys 3 Quick Start Guide
Sub-System Board 5563 Fresno (MAXREFDES11#): 16-Bit High-Accuracy 0 to 10V Input Isolated Analog Front End (AFE)
Sub-System Board 5562 Campbell (MAXREFDES4#): 16-Bit High-Accuracy 4-20mA Input Isolated Analog Front End (AFE)
Sub-System Board 5561 Santa Fe (MAXREFDES5#): 16-Bit High Accuracy Multi-Input Isolated Analog Front End (AFE)
Sub-System Board 5512 Riverside (MAXREFDES8#): 3.3V Input, 12V (15V) Output Isolated Power Supply
Sub-System Board 5510 Lakewood (MAXREFDES7#): 3.3V Input, ±12V (±15V) Output Isolated Power Supply
Tutorial 4701 Introduction to Programmable Logic Controllers (PLCs) and the Operational Function of Main System Modules
App Note 4553 Isolated Power Using Capacitors

Quality and Environmental Data

Product Reliability Reports: MAX256.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

CAD Symbols and Footprints

  • MAX256ASA+
  • MAX256ASA+T
  • MAX256ASA/V+
  • MAX256ASA/V+T
    •

    Quality And Environmental

    Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

    Quality Management System >
    Environmental Management System >

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    Related Resources

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    Technical Docs

    Reference Designs