SN6505 Low-Noise Transformer Drivers

Texas Instruments' SN6505 is a low-noise, low-EMI, push-pull transformer driver, specifically designed for small form factor, isolated power supplies. It drives low-profile, center-tapped transformers from a 2.25 V to 5 V_DC power supply. Ultra-low noise and EMI are achieved by slew rate control of the output switch voltage and through spread spectrum clocking (SSC). The SN6505 consists of an oscillator followed by a gate drive circuit that provides the complementary output signals to drive ground-referenced N-channel power switches. The device includes two 1 A power-MOSFET switches to ensure start-up under heavy loads. The switching clock can also be provided externally for accurate placement of switcher harmonics, or when operating with multiple transformer drivers. The internal protection features include a 1.7 A current limiting, under-voltage lockout, thermal shutdown, and break-before-make circuitry. SN6505 includes a soft-start feature that prevents high inrush current during power up with large load capacitors. The SN6505 is available in a small 6-pin SOT23/DBV package. The device operation is characterized for a temperature range from -55°C to 125°C.

TI Design Link: Reference Design for Isolated Gate Driver Power Stage with Active Miller Clamp for Solar Inverters