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ADM1177:  Hot Swap Controller and Digital Power Monitor with Soft Start Pin

Product Details

The ADM1177 is an integrated hot swap controller that offers digital current and voltage monitoring via an on-chip, 12-bit analog-to-digital converter (ADC), communicated through an I2C interface.

An internal current sense amplifier senses voltage across the sense resistor in the power path via the VCC pin and the SENSE pin.

The ADM1177 limits the current through this resistor by control-ling the gate voltage of an external N-channel FET in the power path, via the GATE pin. The sense voltage (and, therefore, the inrush current) is kept below a preset maximum.

The ADM1177 protects the external FET by limiting the time that it spends with maximum current running through it. This current limit period is set by the choice of capacitor attached to the TIMER pin. Additionally, the device provides protection from overcurrent events that may occur once the hot swap event is complete. In the case of a short-circuit event, the current in the sense resistor exceeds an overcurrent trip threshold, and the FET is switched off immediately by pulling down the GATE pin.

A soft start (SS) pin is also included. This gives the user control over the reference on the current sense amplifier. An internal current source charges a capacitor on this pin at startup, allowing the user to set the profile of the initial current ramp. A voltage can also be driven on this pin to alter the reference.

A 12-bit ADC can measure the current seen in the sense resistor, as well as the supply voltage on the VCC pin. An industry-standard I2C interface allows a controller to read current and voltage data from the ADC. Measurements can be initiated by an I2C command. Alternatively, the ADC can run continuously, and the user can read the latest conversion data whenever it is required. Up to four unique I2C addresses can be created, depending on the way the ADR pin is connected.

The ADM1177 is packaged in a 10-lead MSOP.


  • Power monitoring/power budgeting
  • Central office equipment
  • Telecommunication and data communication equipment
  • PCs/servers


  • Allows safe board insertion and removal from a live backplane
  • Controls supply voltages from 3.15 V to 16.5 V
  • Precision current sense amplifier
  • Precision voltage input
  • 12-bit ADC for current and voltage readback
  • Charge pumped gate drive for external N-channel FET
  • Active high ON pin
  • 10-lead MSOP
  • Adjustable analog current limit with circuit breaker
  • ±3% accurate hot swap current limit level
  • Fast response limits peak fault current
  • Automatic retry or latch-off on current fault
  • Programmable hot swap timing via TIMER pin
  • Soft start pin for reference adjustment and programming of initial current ramp rate
  • I2C fast mode-compliant interface (400 kHz maximum)

Typical Application Circuit


Title Content Type File Type
ADM1177: Hot Swap Controller and Digital Power Monitor with Soft Start Pin Data Sheet (Rev C, 10/2012) (pdf, 708 kB) Data Sheets PDF
Webcast: Hot Swap Design, How to Get it Right
This webcast closely examines the components of a hot swap design and find out what's critical to getting it right.
Webcasts WEBCAST
UG-659: ADM1175/ADM1176/ADM1177/ADM1178 Evaluation Kit User Guide  (pdf, 1024 kB) Evaluation Kit Manuals PDF
UG-404: USB-SDP-CABLEZ Serial Interface Board  (pdf, 536 kB)
The USB-SDP-CABLEZ is primarily used to communicate with certain Analog Devices evaluation boards.
User Guides PDF
Dual Buck Controller Cuts Bill-of-material Costs by 15 Percent
(EE Times, 6/6/2006)
Product Reviews HTML
Power System Management (Spring 2007)  (pdf, 1170 kB) Overview PDF
Hot Swap And Power Monitoring Bulletin  (pdf, 3226 kB) Solutions Bulletins PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
ADM1175-78 & ADM1191-92 Evaluation Software
This version of software supports Windows XP, Windows Vista, and Windows 7 and is recommended for new installations. It requires the ADMxxxx Common Run-time to be installed in order to provide driver support for the all supported I2C interfaces. This includes the USB-SDP-CABLEZ, USB-SMBUS-CABLEZ and USB-5PSMBUS-CABLEZ interfaces.
Evaluation Software HTML
ADMxxxx Common Run-Time
This run-time installer is shared between the SuperSequencer, ADM1175-92 and ADM1293/4 and the Hot Swap and Power Monitor tools. Contains driver support for the USB-SMBUS-CABLEZ and USB-SDP-CABLEZ interface connectors.
Evaluation Software HTML

Evaluation Kits & Symbols & Footprints

Evaluation Boards & KitsView the Evaluation Boards and Kits page for documentation and purchasing

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

SampleSample & Buy

Price, packaging, availability

ADM1177 Model Options
Model Package Pins Temp.
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
ADM1177-1ARMZ-R7 Status: Production 10 ld MSOP 10 Ind Reel, 1000 - $2.53 Y  Material Info PCN Purchase Sample
ADM1177-2ARMZ-R7 Status: Production 10 ld MSOP 10 Ind Reel, 1000 - $2.53 Y  Material Info PCN Purchase Sample
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

ADM1177 Evaluation Board
Model Description Price RoHS View PCN/ PDN Check Inventory/
EVAL-ADM1177EBZ Status: Production Evaluation Board $151.80 Yes -
USB-SDP-CABLEZ Status: Production USB to Serial I/O Interface. Required. Only one neeed for multiple eval kits. $89.00 Yes -

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.

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