1

Low Input Voltage, High Efficiency Synchronous Boost

Converter with 1A Switch

ISL9111, ISL9111A

The ISL9111 and ISL9111A provide a power supply solution

for single-cell, dual-cell, or three-cell alkaline, NiCd or NiMH

battery-powered applications. The device has a typical 0.8V

start-up voltage and is capable of supplying up to 5.25V output

voltage. Both devices are guaranteed to supply 100mA from a

single-cell input and 240mA from a dual-cell input when

output is 3.3V. High 1.2MHz switching frequency allows for the

use of tiny, low-profile inductors and ceramic capacitors to

minimize the size of the solution.

The ISL9111 and ISL9111A are internally compensated, fully

integrated synchronous boost converters optimized for

efficiency with minimal external components. At light load, the

device enters skip mode and consumes only 20µA of

quiescent current, resulting in higher efficiency at light loads

and maximum battery life.

The ISL9111 and ISL9111A address both rechargeable and

non-rechargeable battery applications. The ISL9111 has a

UVLO feature, which will internally shut off at 0.7V protecting a

rechargeable battery. The ISL9111A has this feature disabled

to maximize the usable life of a non-rechargeable single cell

battery. The parts are available in fixed 3.0V, 3.3V and 5.0V

output voltage versions or an adjustable output voltage version

(ADJ). The fixed output voltage version also provides a FAULT

pin for fault condition monitoring. The ISL9111 and ISL9111A

are available in a 6 Ld SOT-23 package.

Features

• Up to 97% Efficiency at Typical Operating Conditions

• Minimum Start-up Voltage

- 0.8V (ISL9111)

- 0.6V (ISL9111A)

• Minimum Operating Voltage

- 0.7V (ISL9111)

- 0.5V (ISL9111A)

•Low Quiescent Current: 20μA (Typical)

• Logic Control Shutdown (Iq < 1µA)

• Output Voltage Up to 5.25V

• Output Disconnect During Shutdown

• Skip Mode Under Light Load Condition

• Undervoltage Lockout (ISL9111 Only)

• Fault Protection: OVP (ADJ Version Only), OTP, Short Circuit

•6 Ld SOT-23 Package

Applications

• Products Including Portable HDMI and USB-OTG

• Personal Medical Products

• Wireless Mouse/Keyboard

•Bluetooth Headsets

• MP3/MP4 Players/DSC

• Single-cell, Dual-cell and Triple-cell Alkaline, NiCd, NiMH

Powered Products

FIGURE 1. TYPICAL APPLICATION

FIGURE 2. FIXED 5V EFFICIENCY

SW

EN

GND

FAULT

VOUT

VIN

6

5

4

3

2

1

VIN

VOUT

4.7µH

4.7µF

4.7µF

1k

ISL9111: 3.0/3.3/5.0V, ISL9111A: 3.0/3.3/5.0V

60

65

70

75

80

85

90

95

100

0.1

1

10

100

1000

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

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

Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.

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

December 7, 2011

FN7602.3