1
DATA SHORT
To request the full datasheet, please visit www.intersil.com/products/ISL91127
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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High Efficiency Buck-Boost Regulator with 4.5A Switches
ISL91127
The ISL91127 is a high-current, buck-boost switching regulator
for systems using new battery chemistries. It uses Intersil’s
proprietary buck-boost algorithm to maintain voltage
regulation while providing excellent efficiency and very low
output voltage ripple when the input voltage is close to the
output voltage.
The ISL91127 is capable of delivering at least 2.1A continuous
output current (V
OUT
= 3.3V) across a battery voltage range of
2.5V to 4.35V. This maximizes the energy utilization of
advanced, single-cell Li-ion battery chemistries that have
significant capacity left at voltages below the system voltage.
Its fully synchronous low ON-resistance 4-switch architecture
and a low quiescent current of only 30µA optimize efficiency
under all load conditions.
The ISL91127 supports stand-alone applications with a fixed
3.3V or 3.5V output voltage or adjustable output voltage with
an external resistor divider. Output voltages as low as 1V or as
high as 5.2V are supported.
The ISL91127 is available in a 20 bump, 0.4mm pitch WLCSP
(2.15mmx1.74mm) with a 2.5MHz switching frequency, which
further reduces the size of external components.
Related Literature
• For a full list of related documents, visit our website
- ISL91127
product page
Features
• Accepts input voltages above or below regulated output
voltage
• Automatic and seamless transitions between Buck and
Boost modes
• Input voltage range: 1.8V to 5.5V
• Continuous output current: up to 2.1A (PVIN = 2.5V,
V
OUT
=3.3V)
• High efficiency: up to 96%
• 30µA quiescent current maximizes light-load efficiency
• 2.5MHz switching frequency minimizes external component
size
• Fully protected for short-circuit, over-temperature, and
undervoltage
• Small 2.15mmx1.74mm WLCSP
Applications
• Brownout-free system voltage for smartphones and tablet
PCs
• Wireless communication devices
• 2G/3G/4G RF power amplifiers
FIGURE 1. TYPICAL APPLICATION: V
OUT
= 3.3V FIGURE 2. EFFICIENCY: V
OUT
= 3.3V
PVIN
V
IN =
1.8V TO 5.5V
V
OUT
= 3.3V
IS L911 27IIN Z
VIN
EN
LX1
LX2
VOUT
FB
SGND
PGND
C
1
10µF
L
1
1µH
C
2
2x22µF
MODE
100
1 10 100 1000
LOAD CURRENT (mA)
V
IN
= 3V
V
IN
= 3.3V
V
IN
=4V
V
IN
= 3.6V
V
IN
= 2.5V
January 5, 2017
FN8418.3
