1

Buck PWM Controller with Internal Compensation and

External Reference Tracking

ISL95873

The ISL95873 is a Single-Phase Synchronous-Buck PWM

controller featuring Intersil’s proprietary R4™ Technology. The

R4™ modulator has integrated compensation, fast transient

performance, accurate switching frequency control, and

excellent light-load efficiency. These technology advances,

together with integrated MOSFET drivers and a Schottky

bootstrap diode, allow for a high performance regulator that is

highly compact and needs few external components.

Differential remote sensing of the output voltage is an

additional feature. For maximum efficiency, the converter

automatically enters diode-emulation mode (DEM) during

light-load conditions, such as system standby.

The ISL95873 accepts a wide 3.3V to 25V input voltage range,

making it ideal for systems that run on battery or AC-adapter

power sources. It also is a low-cost solution for applications

requiring tracking of an external reference voltage during

soft-start. When the external reference level meets the internal

reference voltage, the ISL95873 switches from the external

reference to the internal reference. The external reference is

only used during soft-start.

Features

• External reference tracking

• Intersil’s R4™ modulator technology

- Internal compensation

- Fast, optimal transient response

• Input voltage range: 3.3V to 25V

• Output voltage range: 0.5V to 3.3V

• Precision voltage regulation

- ±0.5% System accuracy over -10°C to +100°C

•Output voltage remote sense

• Fixed 300kHz PWM frequency in continuous conduction

- Proprietary frequency control loop

• Automatic diode emulation mode for highest efficiency

• Power-good monitor for soft-start and fault detection

Applications

• Compact buck regulators requiring external tracking

FIGURE 1. ISL95873 APPLICATION SCHEMATIC WITH DCR CURRENT SENSE

RTN

GND

REFIN

EN

3.3V TO 25V

0.5V TO 3.3V

CO

CIN

GPIO

11

UGATE

BOOT

2

1

12

9

PGOOD

PHASE

4

3

10

+5V

RTN1

RTN1

0

EXTERNAL

REFERENCE

VOLTAGE

December 10, 2012

FN8390.0

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

R3 , R4 Modulator Technologies and Intersil (and design) are trademarks owned by Intersil Corporation or one of its subsidiaries.

All other trademarks mentioned are the property of their respective owners.