Features and Benefits
▪ Quasi-resonant topology IC  Low EMI noise and soft
switching
▪ Bottom-skip mode  Improved system efficiency over
the entire output load by avoiding increase of switching
frequency
▪ Standby mode  Lowers input power at very light output
load condition
▪ Avalanche-guaranteed MOSFET  Improves system-level
reliability and does not require VDSS derating
▪ 650 VDSS / 0.385 Ω RDS(on)
▪ Various protections  Improved system-level reliability
▫ Pulse-by-pulse drain overcurrent limiting
▫ Overvoltage Protection (bias winding voltage sensing),
with latch
▫ Overload Protection with latch
▫ Maximum on-time limit

Description
The STR-X6759N is a quasi-resonant topology IC designed for
SMPS applications. It shows lower EMI noise characteristics
than conventional PWM solutions, especially at greater than
2 MHz. It also provides a soft-switching mode to turn on the
internal MOSFET at close to zero voltage (VDS bottom point)
by use of the resonant characteristic of primary inductance
and a resonant capacitor.
The package is a fully molded TO-3P, which contains the
controller chip (MIC) and MOSFET, enabling output
power up to 280 W at 120 VAC input. The bottom-skip
mode skips the first bottom of VDS and turns on the MOSFET
at the second bottom point, to minimize an increase of
operating frequency at light output load, improving systemlevel efficiency over the entire load range.
A standby mode is executed by clamping the secondary output.
In general applications, standby mode reduces input power.
The soft-start mode minimizes surge voltage and reduces power
stress to the MOSFET and to the secondary rectifying diodes
during the start-up sequence.
Various protections such as overvoltage, overload, overcurrent,
maximum on-time protections and avalanche-energy guaranteed
MOSFET secure good system-level reliability