FN8659
Rev.2.00
May 23, 2017
ISL9120
Compact High Efficiency Low Power Buck-Boost Regulator
DATA SHORT
FN8659 Rev.2.00 Page 1 of 2
May 23, 2017
To request the full datasheet, visit www.intersil.com/products/ISL9120
The ISL9120 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 ISL9120 also has automatic bypass
functionality. 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 ISL9120 also has forced
bypass functionality with the use of the BYP pin.
This device is capable of delivering up to 800mA of output
current (VIN = 2.5V, VOUT = 3.3V) and provides excellent
efficiency due to its adaptive current limit Pulse Frequency
Modulation (PFM) control architecture.
The ISL9120 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 forced bypass mode.
The ISL9120 requires only a single inductor and very few
external components. Power supply solution size is minimized
by a 1.41mmx1.41mm WLCSP.
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 (VIN = 2.5V, VOUT = 3.3V)
• High efficiency: up to 98%
• 41µA quiescent current maximizes light-load efficiency
• Fully protected for over-temperature and undervoltage
• Small 1.41m x1.41mm WLCSP
Applications
• Smartphones and tablets
• Portable consumer and wearable devices
Related Literature
• For a full list of related documents, visit our website
-ISL9120 product page
FIGURE 1. TYPICAL FIXED OUTPUT APPLICATION FIGURE 2. EFFICIENCY: VOUT = 3.3V, TA = +25°C
VOUT = 3.3V
VOUT
FB C2
22F TO 47F
VIN
VIN =
1.8V TO 5.5V
C1
10F
ISL9120IINZ
GND PGND
LX1
LX2
L1
1H
EN
BYP
FORCED BYPASS
BUCK-BOOST
ENABLE
DISABLE
70
75
80
85
90
95
100
1 10 100 1000
EFFICIENCY (%)
OUTPUT CURRENT (mA)
VIN = 3.6V
VIN = 3V
VIN = 4V VIN = 3.4V
VIN = 2.5V