DATASHEET ISL95870, ISL95870A, ISL95870B FN6899 Rev.1.00 PWM DC/DC Controller with VID Inputs for Portable GPU Core-Voltage Regulator December 2, 2013 The ISL95870, ISL95870A, ISL95870B ICs are Single-Phase Features Synchronous-Buck PWM regulators featuring Intersils 4 Input Voltage Range: 3.3V to 25V proprietary R Technology. The wide 3.3V to 25V input voltage range is ideal for systems that run on battery or Output Voltage Range: 0.5V to 5V AC-adapter power sources. The ISL95870A and ISL95870B Precision Regulation are low-cost solutions for applications requiring dynamically 4 -Proprietary R Frequency Control Loop selected slew-rate controlled output voltages. The soft-start - 0.5% System Accuracy Over -10C to +100C and dynamic setpoint slew-rates are capacitor programmed. Voltage identification logic-inputs select four (ISL95870A, Optimal Transient Response ISL95870B) resistor-programmed setpoint reference voltages 4 - Intersils R Modulator Technology that directly set the output voltage of the converter between 0.5V and 1.5V, and up to 5V with a feedback voltage divider. Output Remote Sense 3 4 Compared with R modulator, the R modulator has Extremely Flexible Output Voltage Programmability equivalent light-load efficiency, faster transient performance, - 2-Bit VID Selects Four Independent Setpoint Voltages for accurately regulated frequency control and all internal ISL95870B compensation. These updates, together with integrated - 2-Bit VID Selects Four Dependent or Three Independent MOSFET drivers and schottky bootstrap diode, allow for a Setpoint Voltages for ISL95870A high-performance regulator that is highly compact and needs - Simple Resistor Programming of Setpoint Voltages few external components. The differential remote sensing for output voltage and selectable switching frequency are another Selectable 300kHz, 500kHz, 600kHz or 1MHz PWM two new functions. For maximum efficiency, the converter Frequency in Continuous Conduction automatically enters diode-emulation mode (DEM) during Automatic Diode Emulation Mode for Highest Efficiency light-load conditions such as system standby. Power-Good Monitor for Soft-Start and Fault Detection Applications Mobile PC Graphical Processing Unit VCC Rail Mobile PC I/O Controller Hub (ICH) VCC Rail Mobile PC Memory Controller Hub (GMCH) VCC Rail +5V R VCC C VCC C PVCC V IN 3.3V TO 25V CIN Q HS 1 12 R GND BOOT FB1 RTN1 2 11 RTN V UGATE L OUT O 0.5V TO 5V 3 10 EN GPIO PHASE Q LS 4 9 CO SREF PGOOD C SEN RTN1 C BOOT R O 0 R FB R OFS FIGURE 1. ISL95870 APPLICATION SCHEMATIC WITH ONE OUTPUT VOLTAGE SETPOINT AND DCR CURRENT SENSE FN6899 Rev.1.00 Page 1 of 28 December 2, 2013 R OFS1 C SOFT 5 16 PGND FSEL 15 6 LGATE FB 14 7 PVCC OCSET 13 8 VCC VO R PGOOD R OCSETISL95870, ISL95870A, ISL95870B Table of Contents Applications Schematics: ISL95870 3 Applications Schematics: ISL95870A . 4 Applications Schematics: ISL95870B . 5 Block Diagram 6 ISL95870 Functional Pin Descriptions 8 ISL95870A Functional Pin Descriptions . 9 ISL95870B Functional Pin Descriptions 10 Absolute Maximum Ratings 12 Thermal Information 12 Recommended Operating Conditions . 12 Electrical Specifications 12 Theory of Operation . 15 Power-On Reset . 15 Start-Up Timing . 15 Start-Up and Voltage-Step Operation for ISL95870 . 15 Start-Up and Voltage-Step Operation for ISL95870A, ISL95870B . 15 Output Voltage Programming for ISL95870 . 16 Output Voltage Programming for ISL95870A 16 Output Voltage Programming for ISL95870B 17 High Output Voltage Programming . 18 R4 Modulator . 18 Stability 19 Transient Response 19 Diode Emulation 20 Overcurrent . 20 Overvoltage . 21 Undervoltage . 21 Over-Temperature . 21 PGOOD Monitor . 21 Integrated MOSFET Gate-Drivers . 21 Adaptive Shoot-Through Protection . 21 General Application Design Guide 22 Selecting the LC Output Filter . 22 Selecting the Input Capacitor 22 Selecting the Bootstrap Capacitor 23 Driver Power Dissipation 23 MOSFET Selection and Considerations 23 Layout Considerations 24 Revision History 25 About Intersil 25 L16.2.6x1.8A 16 LEAD ULTRA THIN QUAD FLAT NO-LEAD PLASTIC PACKAGE . 26 L20.3.2x1.8 20 LEAD ULTRA THIN QUAD FLAT NO-LEAD PLASTIC PACKAGE (UTQFN) 27 L20.3x4 20 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE 28 FN6899 Rev.1.00 Page 2 of 28 December 2, 2013