LT2940 - Power and Current Monitor


  • Four-Quadrant Power Measurement
  • ±5% Power Measurement Accuracy
  • 4V to 80V High Side Sense, 100V Max
  • Current Mode Power and Current Outputs
  • Output Bandwidth Exceeds 500kHz
  • ±3% Current Measurement Accuracy
  • 6V to 80V Supply Range, 100V Max
  • Inverting and Noninverting Open-Collector Comparator Outputs
  • Available in 12-Pin DFN (3mm × 3mm) and 12-Lead MSOP Packages

Typical Application

LT2940 Typical Application
LT2940 Typical Application


The LT2940 measures a high side current and a differential voltage, multiplies them and outputs a current proportional to instantaneous power. Bidirectional high side currents and bipolar voltage differences are correctly handled by the four-quadrant multiplier and push-pull output stage, which allows the LT2940 to indicate forward and reverse power flow.

An integrated comparator with inverting and noninverting open-collector outputs makes the LT2940 a complete power level monitor. In addition, an output current proportional to the sensed high side current allows current monitoring. The current mode outputs make scaling, filtering and time integration as simple as selecting external resistors and/or capacitors.


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LT2940CDD#PBF 3x3 DFN-12 DD C 05-08-1725 Yes
LT2940CDD#TRPBF 3x3 DFN-12 DD C 05-08-1725 Yes
LT2940CMS#PBF MS-12 MS C 05-08-1668 Yes
LT2940CMS#TRPBF MS-12 MS C 05-08-1668 Yes
LT2940IDD#PBF 3x3 DFN-12 DD I 05-08-1725 Yes
LT2940IDD#TRPBF 3x3 DFN-12 DD I 05-08-1725 Yes
LT2940IMS#PBF MS-12 MS I 05-08-1668 Yes
LT2940IMS#TRPBF MS-12 MS I 05-08-1668 Yes

LT2940 Package Drawing
LT2940 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LT2940CDD#PBF 3x3 DFN-12 C $2.93 $2.05 Yes
LT2940CDD#TRPBF 3x3 DFN-12 C $2.11 Yes
LT2940CMS#PBF MS-12 C $2.93 $2.05 Yes
LT2940CMS#TRPBF MS-12 C $2.11 Yes
LT2940IDD#PBF 3x3 DFN-12 I $3.51 $2.46 Yes
LT2940IDD#TRPBF 3x3 DFN-12 I $2.52 Yes
LT2940IMS#PBF MS-12 I $3.51 $2.46 Yes
LT2940IMS#TRPBF MS-12 I $2.52 Yes
Buy NowRequest Samples
* 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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1495A LT2940| Power & Current Monitor $25.00
Buy Now
Click here to view our complete list of demo boards


  • Board Level Power and Current Monitoring
  • Line Card and Server Power Monitoring
  • Power Sense Circuit Breaker
  • Power Control Loops
  • Power/Energy Meters
  • Battery Charger Metering

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email with questions and comments.

Design Tools


LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:

Technical Support