DATASHEET ISL91127IR FN8859 Rev 1.00 High Efficiency Buck-Boost Regulator with 4.5A Switches August 3, 2016 The ISL91127IR is a high-current buck-boost switching Features regulator for systems using new battery chemistries. It uses Accepts input voltages above or below regulated output Intersils proprietary buck-boost algorithm to maintain voltage voltage regulation while providing excellent efficiency and very low output voltage ripple when the input voltage is close to the Automatic and seamless transitions between buck and output voltage. boost modes The ISL91127IR is capable of delivering at least 2A continuous Input voltage range: 1.8V to 5.5V output current (V = 3.3V) over a battery voltage range of OUT Output current: up to 2A (PVIN = 2.5V, V = 3.3V) OUT 2.5V to 4.35V. This maximizes the energy utilization of High efficiency: up to 96% advanced single-cell Li-ion battery chemistries that have significant capacity left at voltages below the system voltage. 30A quiescent current maximizes light-load efficiency Its fully synchronous low ON-resistance, 4-switch architecture 2.5MHz switching frequency minimizes external component and a low quiescent current of only 30A optimize efficiency size under all load conditions. Fully protected for short-circuit, over-temperature and The ISL91127IR supports stand-alone applications with a fixed undervoltage 3.3V or 3.5V output voltage or adjustable output voltage with 20 Ld 4mmx4mm QFN package an external resistor divider. Output voltages as low as 1.0V or as high as 5.2V are supported. Applications The ISL91127IR is available in a 20 Ld, 0.5mm pitch QFN Handheld and battery powered consumer and medical (4mmx4mm) package. The 2.5MHz switching frequency devices further reduces the size of external components. Brownout free system voltage for smartphones and tablet PCs Related Literature Wireless communication devices UG080, ISL91127IRN-EVZ, ISL91127IR2A-EVZ, ISL91127IRA-EVZ Evaluation Boards User Guide 2G/3G/4G RF power amplifiers 100 ISL91127IRNZ 95 V 1.8V TO 5.5V IN = LX1 PVIN C L 1 1 90 1H 10F LX2 V = 3.3V VIN OUT 85 VOUT EN C VIN = 2.5V 2 2x22F FB 80 VIN = 3.3V MODE VIN = 3.6V 75 SGND PGND VIN = 4V 70 1 10 100 1000 LOAD CURRENT (mA) FIGURE 1. TYPICAL APPLICATION: V = 3.3V FIGURE 2. EFFICIENCY: V = 3.3V, T = +25C OUT OUT A FN8859 Rev 1.00 Page 1 of 12 August 3, 2016 EFFICIENCY (%)ISL91127IR Block Diagram LX1 LX2 4 5 1 2 6 7 Q1 17 PVIN 8 18 Q4 VOUT 9 19 GATE DRIVERS 20 AND EN ANTI-SHOOT 11 EN THRU - + Q2 Q3 VIN 10 VREF EN PGND 3 VIN MONITOR VOUT CLAMP THERMAL 13 SHUTDOWN SGND CURRENT 14 DETECT EN CONTROL 12 MODE 16 NC ADJ OSC OUTPUT EN ERROR FB 15 AMP - FIXED + + REF OUTPUT - COMP VOLTAGE PROG. FIGURE 3. BLOCK DIAGRAM FN8859 Rev 1.00 Page 2 of 12 August 3, 2016 REVERSE CURRENT