Product details


We are not able to display this information. Please refer to the product data sheet.

Package | Pins | Size

SOIC (D) 16 59 mm² 9.9 x 6 open-in-new Find other eFuses & hot swap controllers


  • Integrated 0.075- Power MOSFET
  • 3 V to 6 V Operation
  • External Analog Control of Fault Current from 0 A to 4 A
  • Independent Analog Control of Current Limit Up to 5 A
  • Fast Overload Protection
  • Unidirectional Switch
  • Minimal External Components
  • 1-uA ICC When Disabled
  • Programmable On Time
  • Programmable Start Delay
  • Fixed 3% Duty Cycle
open-in-new Find other eFuses & hot swap controllers


The UCC3918 low on-resistance hot swap power manager provides complete power management, hot swap capability, and circuit breaker functions. The only components needed to operate the device, other than supply bypassing, are a timing capacitor, and two programming resistors. All control and housekeeping functions are integrated, and externally programmable. These include the fault current level, maximum output sourcing current, maximum fault time, and startup delay. In the event of a constant fault, the internal fixed 3%duty cycle ratio limits the average output power. The IFAULT pin allows linear programming of the fault level current from 0 A to 4 A.

Fast overload protection is accomplished by an additional overload comparator. Its threshold is internally set above the maximum sourcing current limit setting. In the event of a short circuit or extreme current condition, this comparator is tripped, shutting down the output. This function is needed since the maximum sourcing current limit loop has a finite bandwidth.

When the output current is below the fault level, the output MOSFET is switched on with a nominal resistance of 0.075 . When the output current exceeds the fault level or the maximum sourcing level, the output remains on, but the fault timer starts charging a capacitor connected to the CT pin (CT). Once CT charges to a preset threshold, the switch is turned off, and remains off for 30 times the programmed fault time. When the output current reaches the maximum sourcing level, the MOSFET transitions from a switch to a constant current source.

The UCC3918 is designed for unidirectional current flow, emulating an ideal diode in series with the power switch. This feature is particularly attractive in applications where many devices are powering a common bus, such as with SCSI termintation power (Termpwr). The UCC3918 can also be put into the sleep mode, drawing only 1 uA of supply current.

Other features include an open-drain fault output indicator, thermal shutdown, undervoltage lockout, 3 V to 6 V operation, and a low thermal resistance small-outline power package.

open-in-new Find other eFuses & hot swap controllers
Similar products you might be interested in
open-in-new Compare products
Similar but not functionally equivalent to the compared device:
TPS2595 ACTIVE 2.7-V to 18-V, 34mΩ, 0.5-4A eFuse with over voltage protection in small WSON package This product has lower Ron and comes in a smaller package.

Technical documentation

= Top documentation for this product selected by TI
No results found. Please clear your search and try again. View all 6
Type Title Date
* Datasheet Low On-Resistance Hot Swap Power Manager datasheet (Rev. B) Jun. 28, 2000
Selection guide Power Management Guide 2018 (Rev. R) Jun. 25, 2018
Technical articles How to simulate a load switch circuit with varying input voltages and loads Nov. 14, 2016
Technical articles How to protect your server from hot swap events Aug. 08, 2016
Technical articles Simplify digital hot swap design using the PI-Commander GUI Jun. 06, 2016
Technical articles New approach for inrush current clamping with smart high side switch Mar. 26, 2015

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Design tools & simulation

PSpice® for TI design and simulation tool
PSPICE-FOR-TI — PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)

CAD/CAE symbols

Package Pins Download
SOIC (D) 16 View options

Ordering & quality

Information included:
  • RoHS
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​


Related videos