Stepper Motor Driver for Bipolar Motors with microstepping & programmable current profile

The L9942 is an integrated stepper motor driver for bipolar stepper motors with microstepping and programmable current profile look-up-table to allow a flexible adaptation of the stepper motor characteristics and intended operating conditions. It is possible to use different current profiles depending on target criteria: audible noise, vibrations, rotation speed or torque. The decay mode used in PWM-current control circuit can be programmed to slow-, fast-, mixed-and auto-decay. In autodecay mode device will use slow decay mode if the current for the next step will increase and the fast decay or mixed decay mode if the current will decrease. The programmable stall detection is useful in case of head lamp leveling and bending light application, by preventing to run the motor too long time in stall for position alignment. If a stall is detected, the alignment process is closed and the noise is minimized.

Key Features

  • Two full bridges for max. 1.3 A load(RDSON = 500 mΩ)
  • Programmable current waveform with look-up table: 9 entries with 5 bit resolution
  • Current regulation by integrated PWM controller and internal current sensing
  • Programmable stepping mode: full, half, mini and microstepping
  • Programmable slew rate for EMC and power dissipation optimization
  • Programmable Fast-, Slow-, Mixed- and Auto-Decay Mode
  • Full-scale current programmable with 3 bit resolution
  • Programmable stall detection
  • Step clock input for reduced μController requirements
  • Very low current consumption in standby mode IS < 3 μA, typ. Tj ≤ 85 °C
  • All outputs short circuit protected with openload, overload current, temperature warning and thermal shutdown
  • The PWM signal of the internal PWM controller is available as digital output.
  • All parameters are guaranteed for 3 V < Vcc < 5.3 V and for 7 V < Vs < 20 V

Circuit Diagram

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Technical Documentation

Product Specifications
Description Version Size
DS4480 DS4480: Integrated stepper motor driver for bipolar stepper motors with microstepping and programmable current profile 7.0 518 KB
Application Notes
Description Version Size
AN3327 AN3327: L9942 back EMF stall detection algorithm 3.0 761 KB
AN2650 AN2650: L9942 stepper motor driver for bipolar stepper motors 3.1 641 KB
Technical Notes & Articles
Description Version Size
TA0354 TA0354: Thermal design calculations for integrated stepper motor driver solutions 1.0 266 KB
User Manuals
Description Version Size
UM0839 UM0839: ST L9942 evaluation board 2.0 816 KB

Publications and Collaterals

Selection Guides
Description Version Size
Automotive powertrain and safety ICs 1.0 838 KB
Smart power solutions for car body applications 4.0 3 MB

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Sample & Buy

Part Number Package Packing Type Operating Temperature (°C) (min) Operating Temperature (°C) (max) Marketing Status Unit Price (US$) * Quantity ECCN (EU) ECCN (US) Country of Origin More info Order from ST Order from Distributors
L9942XP1TR PowerSSO 24 Tape And Reel - - Active - - NEC EAR99 MALAYSIA MORE INFO Get Sample Add to cart DISTRIBUTOR AVAILABILITY
L9942XP1 PowerSSO 24 Tube - - Active - - NEC EAR99 MALAYSIA MORE INFO No availability reported, please contact our Sales office

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office  or our Distributors

Quality & Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
L9942XP1TR ActivePowerSSO 24AutomotiveEcopack2 0
L9942XP1 ActivePowerSSO 24AutomotiveEcopack2 0

(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.