The ISL6269B 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

ISL6269B has an error amplifier that provides ±1 voltage

regulation at the FB pin.

The ISL6269B 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 ISL6269B

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° to +100°C

• Wide input voltage range: +5V to +25V

• 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

• Pre-biased output start-up capability

• Integrated MOSFET drivers and bootstrap diode

• Internal digital soft-start

• Power-good monitor

• PWM minimum frequency above audible spectrum

• 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