1
DATASHEET
Compact High Efficiency Low Power Buck-Boost
Regulator
ISL9120IR
The ISL9120IR is a highly integrated buck-boost switching
regulator that accepts input voltages either above or below the
regulated output voltage. This regulator automatically transitions
between buck and boost modes without significant output
disturbance. The ISL9120IR also has automatic bypass
functionality for when the input voltage is generally within 1% to
2% of the output voltage, there will be a direct bypass connection
between the VIN and VOUT pins. In addition to the automatic
bypass functionality, the ISL9120IR also has a forced bypass
functionality with the use of the BYPS pin.
This device is capable of delivering up to 800mA of output
current (V
IN
= 2.5V, V
OUT
= 3.3V) and provides excellent
efficiency due to its adaptive current limit pulse frequency
modulation (PFM) control architecture.
The ISL9120IR is designed for stand-alone applications and
supports a 3.3V fixed output voltage or variable output voltages
with an external resistor divider. The forced bypass power saving
mode can be chosen if voltage regulation is not required. The
device consumes less than 3.5µA of current over the operating
temperature range in the forced bypass mode.
The ISL9120IR requires only a single inductor and very few
external components. Power supply solution size is minimized by
a 3mmx3mm 12 Ld TQFN package.
Features
• Accepts input voltages above or below regulated output
voltage
• Automatic bypass mode functionality
• Automatic and seamless transitions between buck and boost
modes
• Input voltage range: 1.8V to 5.5V
• Selectable forced bypass power saving mode
• Adaptive multilevel current limit scheme to optimize efficiency
at low and high currents
• Output current: up to 800mA (V
IN
= 2.5V, V
OUT
= 3.3V)
• High efficiency: up to 98%
• 41µA quiescent current maximizes light-load efficiency
• Fully protected for over-temperature and undervoltage
• Small 3mmx3mm 12 Ld TQFN package
Applications
• Smartphones and tablets
• Portable consumer and wearable devices
FIGURE 1. TYPICAL FIXED OUTPUT APPLICATION
FIGURE 2. EFFICIENCY: V
OUT
= 3.3V, T
A
= +25°C
V
OUT
= 3.3V
VOUT
FB
C
2
22µF or 47µF
VIN
V
IN
=
1.8V TO 5.5V
C
1
10µF
ISL9120IRNZ
GND
PGND
LX1
LX2
L
1
1µH
EN
BYPS
BYPASS
BUCK-BOOST
ENABLE
DISABLE
70
75
80
85
90
95
100
1 10 100 1000
OUTPUT CURRENT (mA)
EFFICIENCY (%)
V
IN
= 3.6V
V
IN
= 3.4V
V
IN
= 4V
V
IN
= 2.5V
V
IN
= 3V
February 2, 2016
FN8743.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
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