PDF《DATASHEET》

FN8635 Rev.

4.00 Page

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56 Aug 17,

2017 FN8635 Rev.4.00 Aug 17,

2017 ISL8270M Digital DC/DC PMBus 25A Module DATASHEET The ISL8270M is a 25A step-down DC/DC power supply module with an integrated digital PWM controller, synchronous power switches, an inductor, and passives. Only bulk input and output capacitors are needed to finish the design. The 25A of continuous output current can be delivered without the need for airflow or a heatsink. The thermally enhanced HDA module is capable of dissipating heat directly into the PCB. The ISL8270M uses ChargeMode? control architecture, which responds to a transient load within a single switching cycle. The ISL8270M comes with a preprogrammed configuration for operating in a pin-strap mode: output voltage, switching frequency, and the device SMBus address can be programmed with external resistors. More configurations, such as soft-start and fault limits, can be easily programmed or changed using a PMBus compliant serial bus interface. PMBus can be used to monitor voltages, current, temperatures, and fault status. The ISL8270M is supported by PowerNavigator? software, a Graphical User Interface (GUI) that can be used to configure modules to a desired solution. The ISL8270M is available in a

40 Ld compact 17mmx19mm HDA module with very low profile height of 3.55mm, suitable for automated assembly by standard surface mount equipment. The ISL8270M is RoHS compliant by exemption. Related Literature ? For a full list of related documents, visit our website - ISL8270M product page Features ? Complete digital switch mode power supply - Wide VIN range: 4.5V to 14V - Programmable VOUT range: 0.6V to 5V ? PMBus compliant I2C communication interface - Programmable VOUT, margining, UV/OV, IOUT limit, soft-start/stop, sequencing, and external synchronization - Monitor: VIN, VOUT, IOUT, temperature, duty cycle, switching frequency, and faults ? ChargeMode control architecture ? ±1.0% VOUT accuracy over line, load, and temperature ? Power-good indicator ? Over-temperature protection ? Internal nonvolatile memory and fault logging ? Patented thermally enhanced HDA package ? Intuitive configuration using PowerNavigator Applications ? Server, telecom, storage, and datacom ? Industrial/ATE and networking equipment ? General purpose power for ASIC, FPGA, DSP, and memory FIGURE 1. A COMPLETE DIGITAL SWITCH MODE POWER SUPPLY FIGURE 2. A SMALL PACKAGE FOR HIGH POWER DENSITY ISL8270M VOUT VIN VDD VOUT VSEN+ VSEN- VIN PMBUS INTERFACE VDRVIN VDRVOUT CIN COUT 1? 10? 2.2 SALRT SDA SCL SGND PGND NOTE: 1. Only bulk input and output capacitors are required to finish the design. 19m m 17mm 3.55mm NOT RECOMMENDED FOR NEW DESIGNS RECOMMENDED REPLACEMENT PART ISL8277M ISL8270M FN8635 Rev.4.00 Page

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2017 Table of Contents Ordering Information

3 Firmware Revision History

3 Pin Configuration.4 Pin Descriptions.4 ISL8270M Internal Block Diagram

6 Absolute Maximum Ratings.7 Thermal Information

7 Recommended Operating Conditions

7 Electrical Specifications

7 Typical Performance Curves

10 Efficiency Performance.10 Transient Response Performance

11 Derating Curves

12 Derating Curves

13 Typical Application Circuit

14 Functional Description

16 SMBus Communications.16 Output Voltage Selection

16 Soft-Start Delay and Ramp Times

16 Power-Good

16 Switching Frequency and PLL

17 Loop Compensation

17 Input Undervoltage Lockout (UVLO)17 SMBus Module Address Selection.17 Output Overvoltage Protection.18 Output Prebias Protection

18 Output Overcurrent Protection.18 Thermal Overload Protection