2.7 V to 16.5 V Hot Swap Controller with Current Sense Output Data Sheet ADM1171 FEATURES GENERAL DESCRIPTION Controls supply rails from 2.7 V to 16.5 V The ADM1171 is a hot swap controller that safely enables a Allows protected board removal and insertion to a live printed circuit board to be removed and inserted to a live backplane backplane. This is achieved using an external N-channel power External sense resistor provides adjustable analog current MOSFET with a current control loop that monitors the load limit with circuit breaker current through a sense resistor. An internal charge pump is Peak fault current limited with fast response used to enhance the gate of the N-channel FET. When an Charge pumped gate drive for external N-FET switch overcurrent condition is detected, the gate voltage of the FET is Current sense output reduced to limit the current flowing through the sense resistor. Soft start inrush current control During an overcurrent condition, the TIMER cap determines Automatic retry or latch-off during current fault the amount of time the FET remains at a current limiting mode Undervoltage lockout of operation until it is shut down. The ON (ON-CLR) pin is the 8-lead, TSOT package enable input for the device and can be used to monitor the input supply voltage. The ADM1171 operates with a supply APPLICATIONS voltage ranging from 2.7 V to 16.5 V. Hot swap board insertion: line cards, raid systems The ADM1171 features soft start to provide the user with a Industrial high-side switches/circuit breakers capacitor programmable ramping reference to the internal Electronic circuit breakers current sense comparator. This provides a linearly increasing current limit at startup at a rate set by CSS. This helps to reduce and limit large inrush currents. The ADM1171 also features a current sense output (CSOUT) pin. The voltage on the CSOUT pin represents the voltage drop across the sense resistor gained up by a factor of 20. This device is available in two options: the ADM1171-1 with automatic retry for overcurrent fault and the ADM1171-2 with latch-off for an overcurrent fault. Toggling the ON (ON-CLR) pin resets a latched fault. The ADM1171 is packaged in an 8-lead TSOT. FUNCTIONAL BLOCK DIAGRAM R SENSE Q LONG 1 V = 5V V = 5V IN OUT C LOAD V SENSE CC GATE ADM1171-1 R ON1 SHORT ON SS R ON2 C CSOUT SS TIMER GND C TIMER GND LONG GND Figure 1. Rev. A Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20062013 Analog Devices, Inc. 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Technical Support www.analog.com 05125-001ADM1171 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 ON (ON-CLR) Pin ..................................................................... 12 Applications ....................................................................................... 1 GATE ........................................................................................... 12 General Description ......................................................................... 1 Current Limit Function ............................................................. 12 Functional Block Diagram .............................................................. 1 Calculating the Current Limit .................................................. 12 Revision History ............................................................................... 2 Circuit Breaker Function ........................................................... 12 Specifications ..................................................................................... 3 Timer Function ........................................................................... 13 Absolute Maximum Ratings ............................................................ 4 Power-Up Timing Cycle ............................................................ 13 Thermal Characteristics .............................................................. 4 Circuit Breaker Timing Cycle ................................................... 13 ESD Caution .................................................................................. 4 Automatic Retry or Latched Off ............................................... 14 Pin Configurations and Function Descriptions ........................... 5 Soft Start ...................................................................................... 14 Typical Performance Characteristics ............................................. 6 CSOUT Pin ................................................................................. 14 Theory of Operation ...................................................................... 12 Outline Dimensions ....................................................................... 15 Overview ...................................................................................... 12 Ordering Guide .......................................................................... 15 UVLO ........................................................................................... 12 REVISION HISTORY 11/13Rev. 0 to Rev. A Changes to Figure 39 ...................................................................... 14 7/06Revision 0: Initial Version Rev. A Page 2 of 16