MAX256 3 W H-Bridge Transformer Driver for Isolated DC/DC Converters

Integrated primary-side controller and H-bridge driver for isolated power-supply circuits from Maxim

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 3 W 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 5 V or 3.3 V, and includes under-voltage 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 over-temperature 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.

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  • Provides up to 3 W to the transformer in isolated power supplies
  • Single-supply 5 V or 3.3 V operation
  • Internal resistor-programmable oscillator mode
  • External clock mode with watchdog
  • Disable mode
  • Undervoltage lockout
  • Thermal shutdown
  • Industrial process control
  • Isolated communications links
  • Isolated power supplies
  • Medical equipment
  • Telecommunications

Transformer Driver

ImageManufacturer Part NumberDescriptionOutput ConfigurationApplicationsAvailable Quantity
MAX256ASA+ datasheet linkIC DVR H-BRIDGE 3W 8-SOICMAX256ASA+IC DVR H-BRIDGE 3W 8-SOICHalf Bridge (2)Transformers1948 - Immediate
MAX256ASA+ product page link

Reference Designs/Evaluation Boards

ImageManufacturer Part NumberDescriptionMain PurposeUtilized IC / PartAvailable Quantity
MAXREFDES5# datasheet linkREFERENCE DESIGN SANTA FEMAXREFDES5#REFERENCE DESIGN SANTA FEInterface, Analog Front End (AFE)MAX256, MAX1301, MAX1659, MAX6126, MAX9632, MAX1485026 - Immediate
28 - Factory Stock
MAXREFDES5# product page link
MAXREFDES11# datasheet linkREFERENCE DESIGN FRESNOMAXREFDES11#REFERENCE DESIGN FRESNOInterface, Analog Front End (AFE)MAX256, MAX1659, MAX1735, MAX6126, MAX11100, MAX14850, MAX442508 - Immediate
57 - Factory Stock
MAXREFDES11# product page link
12 - Factory Stock
MAXREFDES8# product page link
MAXREFDES7# datasheet linkREFERENCE DESIGN LAKEWOODMAXREFDES7#REFERENCE DESIGN LAKEWOODPower Management, Transformer DriverMAX256, MAX16592 - Immediate
5 - Factory Stock
MAXREFDES7# product page link
MAXREFDES4# datasheet linkREFERENCE DESIGN CAMPBELLMAXREFDES4#REFERENCE DESIGN CAMPBELLInterface, Analog Front End (AFE)MAX256, MAX1659, MAX6126, MAX11100, MAX14850, MAX442501 - Immediate
69 - Factory Stock
MAXREFDES4# product page link
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Published: 2014-07-09