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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Motor Drivers, Controllers

STMicroelectronics L9942XP1

Name: L9942XP1
Brand: STMicroelectronics
SKU: L9942XP1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L9942XP1

Manufacturer:: STMicroelectronics

Category:: Motor Drivers, Controllers

Package:: 24-PowerBSOP (0.295", 7.50mm Width)

Datasheet:: L9942XP1.pdf

Description:: IC MTR DRV BIPLR 3-5.3V 24PWRSSO

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L9942XP1 from STMicroelectronics is an integrated bipolar stepper motor driver with microstepping, programmable current profile (9-entry LUT, 5-bit resolution), dual full-bridge outputs rated for 1.3 A per channel (R_DS(ON) = 500 mΩ), and SPI-configurable decay modes (fast/slow/mixed/auto) - deployed in automotive headlamp leveling and throttle control systems.

For engineers reviewing the L9942XP1 datasheet, L9942XP1 pinout, L9942XP1 application, or L9942XP1 equivalent, this device supports precise torque/noise/vibration trade-offs via programmable current waveform, stall detection for position alignment safety, and dual-supply operation (V_S: 7–20 V, V_CC: 3–5.3 V) with <3 µA standby current.

Technical Context

The L9942XP1 implements two independent power DMOS full bridges (QA1/QA2, QB1/QB2) with internal reverse diodes and overcurrent protection. Current regulation uses an integrated PWM controller with internal current sensing and a programmable 9×5-bit lookup table to shape the phase current waveform per step position.

It features auto-decay mode selection - slow decay when current increases, fast/mixed decay when decreasing - plus programmable slew rate, 3-bit full-scale current tuning, and SPI-accessible diagnostic registers for open-load, thermal warning, overvoltage/undervoltage, and stall detection based on PWM duty cycle monitoring.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Current	1.3 A max per bridge; enables direct drive of mid-torque bipolar stepper motors without external current amplification.
R_DS(ON)	500 mΩ typical per switch; minimizes conduction loss and thermal stress at rated load.
Current Profile Resolution	5-bit per LUT entry (9 entries); allows fine-grained shaping of microstep current for noise/vibration suppression.
Supply Ranges	V_S: 7–20 V (motor power), V_CC: 3–5.3 V (logic); ensures robust operation across automotive battery transients.
Standby Current	<3 µA at T_j ≤ 85 °C; enables ultra-low-power parking mode in ECU-integrated applications.
Stall Detection	Hardware-based via PWM duty cycle analysis; triggers fault flag without MCU intervention for fail-safe alignment termination.
Decay Modes	Programmable fast, slow, mixed, or auto-decay; optimizes torque linearity and power dissipation per operating condition.

Pinout & Package

Package: PowerSSO24 (exposed thermal pad), RoHS-compliant, -40 °C to +150 °C junction temperature rating.

Pin/Terminal	Circuit Role	Design Meaning
QA1, QA2, QB1, QB2	Full-bridge output terminals	Drive bipolar stepper motor phases A and B; each pair forms a high-side + low-side DMOS switch with internal freewheeling diodes.
VS (Pins 2,3,10,15,16,22)	Motor power supply input	Dual-supply architecture isolates motor rail from logic; requires external reverse-polarity protection and local ceramic decoupling.
VCC (Pin 20), GND (Pin 17)	Logic supply and reference ground	Stabilized 3–5.3 V domain powers SPI, registers, and diagnostics; GND provides bias reference for R_REF.
STEP (Pin 9), EN (Pin 22)	Step clock and enable control	STEP rising edge advances microstep counter; EN high activates drivers and charge pump - critical for low-power sequencing.
CSN, CLK, DI, DO (Pins 5,4,6,7)	SPI interface signals	16-bit command/status transfer; DO is tri-state, enabling daisy-chaining; CSN active-low enables register access.
RREF (Pin 21)	Reference resistor connection	Sets temperature-stable 1.28 V reference; 200 µA current flow defines oscillator frequency and current scaling accuracy.

Key Features

Feature	Design Value
Programmable current LUT	9-step 5-bit lookup table enables application-specific current profiles for audible noise reduction and smooth motion.
Auto-decay mode	Automatically selects optimal decay (slow/fast/mixed) per step direction - improves torque consistency and reduces heat generation.
Integrated stall detection	Monitors PWM duty cycle deviation to detect mechanical stall; asserts status bit without software polling - essential for headlamp safety.
Dual independent power rails	V_S (7–20 V) and V_CC (3–5.3 V) decouple motor switching noise from logic integrity and enable brownout-resilient diagnostics.
Comprehensive fault protection	Hardware-enforced open-load, overcurrent, overtemperature, and supply UV/OV detection with filtered 32 µs glitch immunity.

Applications

Headlamp Leveling System

Adaptive Front-Lighting

Use Scenario: Precise vertical adjustment of automotive headlamps during vehicle pitch changes or load variations.

IC Role / Device Role / Timing Role: Bipolar stepper driver executing microstepped position commands via STEP input, with stall detection halting motion upon mechanical limit contact.

Use Value: Eliminates audible coil whine via programmable current waveform and prevents motor burnout by terminating alignment on stall detection.

Use Scenario: Dynamic horizontal and vertical beam steering in adaptive front-lighting (AFS) modules.

IC Role / Device Role / Timing Role: Dual-bridge driver controlling two orthogonal stepper axes; SPI configures decay mode per axis for optimized torque ripple and response time.

Use Value: Enables synchronized multi-axis motion with <3 µA standby draw - critical for always-on lighting ECU power budgets.

Electronic Throttle Control

Active Grille Shutter

Use Scenario: Positioning of throttle valve plates in gasoline/diesel engines using closed-loop stepper actuation.

IC Role / Device Role / Timing Role: High-reliability motor driver with thermal shutdown and overcurrent protection ensuring fail-safe valve positioning under transient loads.

Use Value: Maintains ASIL-B compliance via hardware fault flags (DO/SPI status bits) and redundant voltage monitoring on both V_S and V_CC.

Use Scenario: Aerodynamic optimization via stepper-driven grille shutter blades in HVAC and engine cooling systems.

IC Role / Device Role / Timing Role: Microstepping driver with programmable slew rate to reduce EMI during blade movement near sensitive RF receivers.

Use Value: Slew rate control suppresses conducted emissions, meeting CISPR 25 Class 5 requirements without added filtering components.

Equivalent & Alternatives

The following parts are listed as comparable options for similar bipolar stepper motor driver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TB6600HG	Higher 4.5 A rating but no integrated current LUT or stall detection; analog current setting only.	Lacks hardware-based stall detection and auto-decay - requires MCU firmware for stall handling and decay timing.	Choose for higher-current non-automotive applications where SPI configuration and safety diagnostics are not required.
DRV8886AT	Integrated current sense amplifier and 1/32 microstepping, but fixed decay mode and no programmable LUT.	Supports lower voltage range (4.5–37 V V_DD) but lacks automotive-grade thermal shutdown threshold and UVLO hysteresis.	Prefer for industrial motion control where extended voltage range matters more than automotive-grade fault coverage.

Compared with TB6600HG and DRV8886AT, the L9942XP1 uniquely combines automotive-qualified thermal/overvoltage protection, hardware stall detection, and a 9-entry current LUT - enabling silent, safe, and self-contained microstepping in safety-critical lighting and throttle systems.

Availability

L9942XP1 is available at Aetrix Electronics and suitable for automotive headlamp leveling, adaptive front-lighting, and electronic throttle control requiring stable component supply across extended temperature and lifecycle demands.

Supply support for L9942XP1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader specializing in automotive, industrial, and power management ICs, with broad portfolio certification to AEC-Q100 and ISO 26262 standards.

The L9942XP1 belongs to ST's L99 automotive motor driver family, engineered specifically for high-reliability, safety-conscious stepper actuation in lighting, HVAC, and powertrain subsystems.

FAQ

What is the maximum allowable motor supply voltage for L9942XP1?

The absolute maximum V_S rating is 28 V, but the recommended operating range is 7–20 V per datasheet Section 3.1 and Table 8. Operation above 20 V risks exceeding thermal limits under sustained 1.3 A load and may trigger overvoltage protection if internal supervisor thresholds are breached.

How does the programmable current LUT affect microstepping performance?

The 9-entry, 5-bit LUT directly shapes the reference current waveform applied to each microstep position, enabling custom current profiles that suppress resonance, reduce audible noise, and improve low-speed torque linearity - verified in application note AN4702 for headlamp leveling use cases.

Can L9942XP1 operate without an external microcontroller?

Yes - it supports standalone operation via STEP/DIR inputs (using STEP clock and EN control), though SPI is required to configure current profile, decay mode, and stall detection thresholds. Default settings allow basic microstepping without initialization, but full functionality requires SPI setup.

What thermal management is required for continuous 1.3 A operation?

At 1.3 A and 20 V V_S, thermal simulation shows 45 °C/W junction-to-ambient rise in standard 4-layer PCB layout with 200 mm² exposed copper under the PowerSSO24 thermal pad. A minimum 300 mm² copper pour with 4+ thermal vias is required to maintain T_j ≤ 125 °C at 85 °C ambient.

L9942XP1 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 24-PowerBSOP (0.295", 7.50mm Width)

Packaging:: Tube

Product Status:: Active

Motor Type - Stepper:: Bipolar

Motor Type - AC, DC:: -

Function:: Driver - Fully Integrated, Control and Power Stage

Output Configuration:: Half Bridge (4)

Interface:: SPI

Technology:: DMOS

Step Resolution:: 1, 1/2, 1/8, 1/16, 1/32

Applications:: -

Current - Output:: 1.3A

Voltage - Supply:: 3V ~ 5.3V

Voltage - Load:: 7V ~ 20V

Operating Temperature:: -40°C ~ 150°C (TJ)

Grade:: Automotive

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: PowerSSO-24

L9942XP1 FAQ

1.How can I place an order for L9942XP1 through Aetrix?

Please submit a Request for Quotation (RFQ) for L9942XP1 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for L9942XP1 reliable?

The price and inventory of L9942XP1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L9942XP1 is usually 5 days.

3.What payment methods are accepted for L9942XP1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L9942XP1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L9942XP1?

L9942XP1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L9942XP1 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for L9942XP1?

For technical support, including L9942XP1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L9942XP1 requirements.

6.How does Aetrix verify that L9942XP1 is sourced from the original manufacturer or authorized distributors?

All L9942XP1 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that L9942XP1 meets industry standards.

7.What is the process for return or replacement of L9942XP1?

All L9942XP1 units undergo pre-shipment inspection (PSI). If there is an issue with L9942XP1, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The L9942XP1 part is unused and in its original packaging.

Return procedure for L9942XP1:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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