DATASHEET ISL85412 FN8378 Rev 1.00 Wide V 150mA Synchronous Buck Regulator IN March 13, 2015 The ISL85412 is a 150mA synchronous buck regulator with an Features input range of 3.5V to 40V. It provides an easy to use, high Wide input voltage range of 3.5V to 40V efficiency low BOM count solution for a variety of applications. Synchronous operation for high efficiency The ISL85412 integrates both high-side and low-side NMOS FETs and features a PFM mode for improved efficiency at light No compensation required loads. This feature can be disabled if forced PWM mode is Integrated high-side and low-side NMOS devices desired. The part switches at a default frequency of 700kHz. Selectable PFM or forced PWM mode at light loads By integrating both NMOS devices and providing internal configuration, minimal external components are required, Internal switching frequency 700kHz reducing BOM count and complexity of design. Continuous output current up to 150mA With the wide V range and reduced BOM, the part provides IN Internal soft-start an easy to implement design solution for a variety of Minimal external components required applications while giving superior performance. It will provide a very robust design for high voltage industrial applications as Power-good and enable functions available well as an efficient solution for battery powered applications. Applications The part is available in a small Pb-free 3mmx3mm TDFN Industrial control plastic package with an operation junction temperature range of -40C to +125C. Medical devices Portable instrumentation Related Literature Distributed power supplies AN1929, ISL85413EVAL1Z, ISL85412EVAL1Z Evaluation Cloud infrastructure Boards AN1931, ISL85413DEMO1Z, ISL85412DEMO1Z Wide VIN Synchronous Buck Regulator - Short Form 100 V OUT U1 ISL85412 90 C4 R1 1 8 MODE MODE FB 80 R2 2 7 BOOT VCC C6 C5 0.1F 70 +3.5 ... +40V 1F 3 6 VIN PG VIN PG 3.3V OUT 1.5V OUT C1 GND 20F 4 5 60 EN 1.8V PHASE EN 1.2V OUT OUT f = 700kHz 5.0V SW OUT 2.5V OUT 1.0V VOUT OUT 50 MAX 150mA L1 Device must be GND C8 connected to GND plane with vias. 40 0.00 0.03 0.06 0.09 0.12 0.15 OUTPUT LOAD (A) FIGURE 1. TYPICAL APPLICATION FIGURE 2. EFFICIENCY vs LOAD, PFM, V = 12V IN FN8378 Rev 1.00 Page 1 of 19 March 13, 2015 9 PGND EFFICIENCY (%)ISL85412 Table of Contents Pin Configuration 3 Pin Descriptions . 3 Functional Block Diagram 4 Ordering Information 4 Absolute Maximum Ratings . 5 Thermal Information . 5 Recommended Operating Conditions 5 Electrical Specifications . 5 Efficiency Curves 7 Typical Performance Curves . 10 Detailed Description 15 Power-On Reset . 15 Soft-Start . 15 Power-Good 15 PWM Control Scheme 15 Light Load Operation . 15 Output Voltage Selection . 16 Protection Features . 16 Overcurrent Protection . 16 Negative Current Limit . 16 Over-Temperature Protection 17 Boot Undervoltage Protection . 17 Application Guidelines 17 Simplifying the Design . 17 Output Inductor Selection . 17 Buck Regulator Output Capacitor Selection 17 Layout Considerations 17 Revision History 18 About Intersil 18 Package Outline Drawing 19 FN8378 Rev 1.00 Page 2 of 19 March 13, 2015