The ISL6269A 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 VR, analogous to the output inductor ripple current. The

AC signal VR enters a window comparator where the lower

threshold is the error amplifier output VCOMP, and the upper

threshold is a programmable voltage reference VW, resulting in

generation of the PWM signal. The voltage reference VW 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 ISL6269A has an error amplifier that

provides ±1 voltage regulation at the FB pin.

The ISL6269A has a 1.5ms digital soft-start and can be

started into a prebiased output voltage. A resistor divider is

used to program the output voltage setpoint. The ISL6269A

can be configured to operate in Continuous Conduction Mode

(CCM) or Diode Emulation Mode (DEM), which improves

light-load efficiency. In CCM the controller always operates as a

synchronous rectifier, however when DEM is enabled, the

low-side MOSFET is permitted to stay off, blocking negative

current flow into the low-side MOSFET from the output

inductor.

Features

? High performance R3? Technology

? Fast transient response

? ±1 regulation accuracy: -10°C to +100°C and

-40°C to +100°C

? Wide input voltage range: +5.0V to +25.0V

? Output voltage range: +0.6V to +3.3V

? Wide output load range: 0A to 25A

? Selectable diode emulation mode for increased light load

efficiency

? Programmable PWM frequency: 200kHz to 600kHz

? Prebiased 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 rDS(ON) overcurrent protection

- Over-temperature protection

- Fault identification by PGOOD pull down resistance

? Pb-free (RoHS compliant)

Applications

? PCI express graphical processing unit

? Auxiliary power rail

? VRM

? Network adapter