LTC2938 - Configurable 4-Supply Monitors with Watchdog Timer


  • Simultaneously Monitors Four (LTC2938) or Six Supplies (LTC2939)
  • Sixteen User-Selectable Combinations of 5V, 3.3V, 2.5V, 1.8V, 1.5V, 1.2V and/or ± Adjustable Voltage Thresholds
  • Guaranteed Threshold Accuracy: ±1.5%
  • Adjustable Reset and Watchdog Timeout
  • Low Supply Current: 80μA Typical
  • Power Supply Glitch Immunity
  • Guaranteed RST for VCC > 1V
  • High Temperature Operation to 125°C
  • 12-Pin 4mm x 3mm DFN or 12-Lead MSOP (LTC2938) and 16-Lead MSOP Package (LTC2939)

Typical Application

LTC2938 Typical Application
LTC2938 Typical Application


The LTC2938/LTC2939 are configurable supply monitors for systems with up to four or six supply voltages that need watchdog supervision. One of sixteen preset or adjustable voltage monitor combinations can be selected using an external resistive divider connected to the program input. The preset voltage thresholds are accurate to ±1.5% over temperature. The LTC2938 and LTC2939 also feature adjustable inputs with a 0.5V nominal threshold.

The reset and watchdog timeout periods are adjustable using external capacitors. Tight voltage threshold accuracy and glitch immunity ensure reliable reset operation without false triggering. The RST output is guaranteed to be in the correct state for VCC down to 1V. Each status output has a weak internal pull-up and may be externally pulled up to a user-defined voltage.

The 80μA supply current makes the LTC2938 and LTC2939 ideal for power conscious systems. The LTC2939 monitors up to six supplies and the LTC2938 monitors up to four supplies.


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
LTC2938CDE#PBF 4x3 DFN-12 DE/UE C 05-08-1695 Yes
LTC2938CDE#TRPBF 4x3 DFN-12 DE/UE C 05-08-1695 Yes
LTC2938CMS#PBF MS-12 MS C 05-08-1668 Yes
LTC2938CMS#TRPBF MS-12 MS C 05-08-1668 Yes
LTC2938HDE#PBF 4x3 DFN-12 DE/UE H 05-08-1695 Yes
LTC2938HDE#TRPBF 4x3 DFN-12 DE/UE H 05-08-1695 Yes
LTC2938HMS#PBF MS-12 MS H 05-08-1668 Yes
LTC2938HMS#TRPBF MS-12 MS H 05-08-1668 Yes
LTC2938IDE#PBF 4x3 DFN-12 DE/UE I 05-08-1695 Yes
LTC2938IDE#TRPBF 4x3 DFN-12 DE/UE I 05-08-1695 Yes
LTC2938IMS#PBF MS-12 MS I 05-08-1668 Yes
LTC2938IMS#TRPBF MS-12 MS I 05-08-1668 Yes

LTC2938 Package Drawing
LTC2938 Package Drawing
LTC2938 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
LTC2938CDE#PBF 4x3 DFN-12 C $3.07 $2.15 Yes
LTC2938CDE#TRPBF 4x3 DFN-12 C $2.21 Yes
LTC2938CMS#PBF MS-12 C $3.07 $2.15 Yes
LTC2938CMS#TRPBF MS-12 C $2.21 Yes
LTC2938HDE#PBF 4x3 DFN-12 H $3.89 $2.72 Yes
LTC2938HDE#TRPBF 4x3 DFN-12 H $2.78 Yes
LTC2938HMS#PBF MS-12 H $3.89 $2.72 Yes
LTC2938HMS#TRPBF MS-12 H $2.78 Yes
LTC2938IDE#PBF 4x3 DFN-12 I $3.53 $2.47 Yes
LTC2938IDE#TRPBF 4x3 DFN-12 I $2.53 Yes
LTC2938IMS#PBF MS-12 I $3.53 $2.47 Yes
LTC2938IMS#TRPBF MS-12 I $2.53 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.

Click here to view our complete list of demo boards


  • Desktop and Notebook Computers
  • Multivoltage Systems
  • Telecom Equipment
  • Network Servers
  • Automotive Control Systems

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

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
  • LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
  • And More!

Technical Support