The ISL6268 IC is a Single-Phase Synchronous-Buck PWM controller featuring Intersil's Robust Ripple Regulator (R³) technology that delivers truly superior dynamic response to input voltage and output load transients. Integrated MOSFET drivers and bootstrap diode result in fewer components and smaller implementation area.

Intersil’s R³ technology combines the best features of fixed-frequency PWM and hysteretic PWM while eliminating many of their shortcomings. R³ technology employs an innovative modulator that synthesizes an AC ripple voltage signal V_R, analogous to the output inductor ripple current. The AC signal V_R enters a window comparator where the lower threshold is the error amplifier output V_COMP, and the upper threshold is a programmable voltage reference V_W, resulting in generation of the PWM signal. The voltage reference V_W sets the steady-state PWM frequency. Both edges of the PWM can be modulated in response to input voltage transients and output load transients, much faster than conventional fixed-frequency PWM controllers. Unlike a conventional hysteretic converter, the ISL6268 has an error amplifier that provides ±1% voltage regulation at the FB pin.

The ISL6268 has a 1.5ms digital soft-start and can be started into a pre-biased output voltage. A resistor divider is used to program the output voltage setpoint. The ISL6268 normally operates in continuous-conduction-mode (CCM), automatically entering diode-emulation-mode (DEM) at low load for optimum efficiency. In CCM the converter operates as a synchronous rectifier. In DEM the low-side MOSFET stays off, blocking negative current flow from the output inductor.

• High performance R³ technology
• Fast transient response
• ±1% regulation accuracy: -10°C to +100°C
• Wide input voltage range: +7.0V to +25.0V
• Output voltage range: +0.6V to +3.3V
• Wide output load range: 0A to 25A
• Diode emulation mode for increased light load efficiency
• Programmable PWM frequency: 200kHz to 600kHz
• Pre-biased output start-up capability
• Integrated MOSFET drivers and bootstrap diode
• Internal digital soft-start
• Power good monitor
• Fault protection
  • Undervoltage protection
  • Soft crowbar overvoltage protection
  • Low-side MOSFET r DS(on) overcurrent protection
  • Over-temperature protection
  • Fault identification by PGOOD pull-down resistance
• Pb-free plus anneal available (RoHS compliant)

• PCI express graphical processing unit
• Auxiliary power rail
• VRM
• Network adapter