High Efficiency Buck-Boost Regulator with 4.5A
The ISL91127IR 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 ISL91127IR is capable of delivering at least 2A continuous
output current (VOUT = 3.3V) over 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
The ISL91127IR 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 1.0V or as
high as 5.2V are supported.
The ISL91127IR is available in a 20 Ld, 0.5mm pitch QFN
(4mmx4mm) package. The 2.5MHz switching frequency further
reduces the size of external components.
• UG080, “ISL91127IRN-EVZ, ISL91127IR2A-EVZ,
ISL91127IRA-EVZ Evaluation Boards User Guide”
• Accepts input voltages above or below regulated output
• Automatic and seamless transitions between buck and boost
• Input voltage range: 1.8V to 5.5V
• Output current: up to 2A (PVIN = 2.5V, VOUT = 3.3V)
• High efficiency: up to 96%
• 30µA quiescent current maximizes light-load efficiency
• 2.5MHz switching frequency minimizes external component
• Fully protected for short-circuit, over-temperature and
• 20 Ld 4mmx4mm QFN package
• Handheld and battery powered consumer and medical devices
• Brownout free system voltage for smartphones and tablet PCs
• Wireless communication devices
• 2G/3G/4G RF power amplifiers
VIN = 1.8V TO 5.5V
VOUT = 3.3V
FIGURE 1. TYPICAL APPLICATION: VOUT = 3.3V
VIN = 2.5V
80 VIN = 3.3V
75 VIN = 3.6V
VIN = 4V
LOAD CURRENT (mA)
FIGURE 2. EFFICIENCY: VOUT = 3.3V, TA = +25°C
August 3, 2016
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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