SN6505B-Q1

The SN6505x-Q1 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. Very low noise and EMI are achieved by slew rate control of the output switch voltage and through Spread Spectrum Clocking (SSC). The SN6505x-Q1 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. SN6505A-Q1 and SN6505B-Q1 include a soft-start feature that prevents high inrush current during power up with large load capacitors. Soft-start feature has been disabled in SN6505D-Q1 for applications that require fast output start-up.SN6505A-Q1 has a 160 kHz internal oscillator for applications that need to minimize emissions whereas SN6505B-Q1 and SN6505D-Q1havea 420 kHz internal oscillators for applications that require higher efficiency and smaller transformer size. The SN6505x-Q1 is available in a small 6-pin SOT23/DBV package. The device operation is characterized for a temperature range from -40°C to 125°C.