1A Spread-Spectrum Push-Pull Transformer Driver for Isolated Power Supplies

The MAX13253 is a 1A push-pull transformer driver designed to provide a simple solution for low-EMI isolated power supplies. The MAX13253 has an internal oscillator and operates from a single +3.0V to +5.5V supply. The transformer’s secondary-to-primary winding ratio defines the output voltage, allowing selection of virtually any isolated output voltage with galvanic isolation.

The MAX13253 features an integrated oscillator driving a pair of N-channel power switches. The driver includes pin-selectable spread-spectrum oscillation and a well-controlled slew rate to reduce EMI. The MAX13253 can optionally be driven by an external clock to further manage EMI. Internal circuitry guarantees a fixed 50% duty cycle to prevent DC current flow through the transformer, regardless of which clock source is used.

The MAX13253 operates with up to 1A of continuous current and features integrated protection including fault detection, overcurrent protection, and thermal shutdown.

The MAX13253 includes a low-current shutdown mode to reduce the overall supply current to less than 5µA (max) when the driver is disabled.

The MAX13253 is available in a small, 10-pin, (3mm x 3mm) TDFN package and is specified over the -40°C to +125°C temperature range.

Applications

* Isolated Analog Front Ends * Isolated Fieldbus Interfaces * Isolated USB Power * Medical Equipment * Power Meter Data Interfaces

* Simple, Flexible Design

* +3.0V to +5.5V Supply Range

* Low RON 300mΩ (max) at 4.5V

* Up to 90% Efficiency

* Provides Up to 1A to the Transformer

* Internal or External Clock Source

* Internal Oscillator Frequency: 250kHz or 600kHz

* Optional Spread-Spectrum Oscillation

* -40°C to +125°C Temperature Range

* Integrated System Protection

* Fault Detection and Indication

* Overcurrent Limiting

* Undervoltage Lockout

* Thermal Shutdown

* Saves Space on Board

* Small 10-Pin TDFN Package (3mm x 3mm)