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.
