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

Product Details

Key Features

Applications/Uses

Parametric specs for Transformer Drivers
VIN (V) (min) 3
VIN (V) (max) 5.5
Driver Output Resistance (Ω) (max) 1
Max. IOUT (A) 1
Topology Full-Bridge
Switching Frequency (kHz) 1000
ICC (mA) (max) 1
Package/Pins SOIC (N)/8
Oper. Temp. (°C) -40 to +125
Budgetary
Price (See Notes)
3.54
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Simplified Block Diagram

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Parameters

Parametric specs for Transformer Drivers
VIN (V) (min) 3
VIN (V) (max) 5.5
Driver Output Resistance (Ω) (max) 1
Max. IOUT (A) 1
Topology Full-Bridge
Switching Frequency (kHz) 1000
ICC (mA) (max) 1
Package/Pins SOIC (N)/8
Oper. Temp. (°C) -40 to +125
Budgetary
Price (See Notes)
3.54

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

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.

Simplified Block Diagram

MAX256: Typical Operating Circuit MAX256: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .