STMicroelectronics

L9981 - Automotive Quad Low-Side Driver | STMicroelectronics

Name: L9981
Brand: STMicroelectronics
Price: 3.25 USD
Availability: InStock

MPN: L9981 ✓ Active

In Stock (99,999) Ships in 1-3 business days

5.5 V to 40 V Vdss 1.5 A Id 0.5 ohm Rds(on) PowerSO-20 Package 1 kHz Speed

$3.25 USD / Unit

MOQ: 1 |

Volume Pricing

Qty	Unit Price	Extended
1	$3.25	$3.25
10	$2.92	$29.20
100	$2.6	$260.00
500	$2.34	$1,170.00
1,000	$2.08	$2,080.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for L9981 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.

Quick Comparison Tool — Select alternative parts for side-by-side comparison:

L9980

✅ Drop-In

STMicroelectronics

📦 PowerSO-20

4 · 1.5 A · 5.5 V to 40 V · 0.5 ohm · 0-100 kHz · SPI · Overcurrent, Thermal Shutdown, Undervoltage Lockout · 10 uA

✓ 99,999 In Stock

$2.1 / Unit

View Datasheet →

TLE6228

✅ Drop-In

📦 PowerSO-20

Cross-brand, similar SPI interface, verify register map

📋 Reference alternative (not in catalog)

MC33882

✅ Drop-In

📦 PowerSO-20

Cross-brand, similar current rating, verify SPI protocol

📋 Reference alternative (not in catalog)

L9981 Maximum Ratings & Electrical Characteristics

Number of Channels	4
Output Current per Channel	1.5 A
Supply Voltage Range	5.5 V to 40 V
On-Resistance (per channel)	0.5 ohm
Interface	SPI
Protection Features	Overcurrent, Overtemperature, Short-circuit
Operating Temperature Range	-40°C to +150°C
Package	PowerSO-20
Mounting Type	Surface Mount
Thermal Resistance (junction-to-ambient)	35 °C/W
Supply Current (standby)	10 µA
Output Leakage Current	1 µA
Switching Frequency (max)	1 kHz
RoHS Status	Compliant
AEC-Q100 Qualified	Yes

L9981 Pin Configuration

Pin 1	OUT1 — Output channel 1
Pin 2	OUT2 — Output channel 2
Pin 3	OUT3 — Output channel 3
Pin 4	OUT4 — Output channel 4
Pin 5	GND — Ground
Pin 6	VCC — Supply voltage
Pin 7	SCK — SPI clock
Pin 8	SDI — SPI data input
Pin 9	SDO — SPI data output
Pin 10	CS — Chip select
Pin 11	RST — Reset
Pin 12	GND — Ground

Safe Operating Area (SOA) & Thermal Characteristics

No official SOA curve available for this component. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.

Typical Applications

L9981 is suitable for 6 applications: Automotive Body Control Module, Industrial Automation, General-Purpose Power Switching, Lighting Control, Relay and Solenoid Driving, Test and Measurement Equipment.

🚗

Automotive Body Control Module

The L9981 is ideal for automotive body control modules (BCMs) where it drives exterior lighting, wiper motors, and door locks. Its 1.5 A per channel output current and 40 V supply range handle typical automotive loads, while the SPI interface enables precise control and diagnostics. The AEC-Q100 qualification ensures reliability in harsh automotive environments, and the wide temperature range (-40°C to +150°C) supports under-hood applications. The integrated protection features (overcurrent, overtemperature, short-circuit) safeguard the BCM and loads, reducing system complexity and improving safety.

Recommended

SPC560B50L3 (MCU controlling the L9981 via SPI) L9177 (Companion power management IC)

🏭

Industrial Automation

In industrial automation, the L9981 drives solenoids, valves, and actuators in control systems. Its robust protection features and wide supply voltage range (5.5 V to 40 V) make it suitable for 24 V industrial buses. The SPI interface allows for remote monitoring and control, enabling predictive maintenance and fault detection. The PowerSO-20 package with exposed pad ensures efficient heat dissipation, even when driving multiple loads simultaneously. The device's low on-resistance (0.5 ohm) minimizes power loss, improving energy efficiency in continuous operation.

Recommended

STM32F407VG (MCU for control and diagnostics) L6206 (Motor driver for related actuators)

🔧

General-Purpose Power Switching

The L9981 serves as a general-purpose quad low-side driver for embedded systems requiring multiple switched loads. Its SPI interface reduces GPIO usage, making it ideal for space-constrained designs. The device can drive resistive loads like LEDs and heaters, as well as inductive loads like relays and solenoids, with built-in freewheeling protection. The wide operating temperature range and AEC-Q100 qualification make it a reliable choice for both commercial and industrial products. The compact PowerSO-20 package simplifies PCB layout, and the exposed pad aids thermal management.

Recommended

STM32L476RG (Low-power MCU for control) L78M05 (Voltage regulator for logic supply)

💡

Lighting Control

The L9981 is well-suited for automotive and industrial lighting control, driving LED modules and incandescent lamps. Its 1.5 A per channel output can handle high inrush currents of lamps, while the overcurrent protection prevents damage. The SPI interface enables PWM dimming and fault reporting, allowing for advanced lighting features. The device's thermal performance ensures stable operation even when all four channels are driving high-power loads. The AEC-Q100 qualification makes it a trusted choice for automotive lighting systems.

Recommended

LED6000 (LED driver for high-power LEDs) STM32F103 (MCU for PWM control)

⚡

Relay and Solenoid Driving

The L9981 is optimized for driving relays and solenoids in automotive and industrial systems. Its low-side configuration and built-in freewheeling protection handle inductive loads safely, preventing voltage spikes. The SPI interface allows for precise control of activation timing and provides diagnostic feedback on coil status. The device's wide supply voltage range accommodates various coil voltages, and the high output current ensures reliable actuation. The robust protection features protect the IC and the load from faults, enhancing system reliability.

Recommended

L9349 (High-side driver for complementary switching) STM8S003 (Low-cost MCU for control)

🔬

Test and Measurement Equipment

In test and measurement equipment, the L9981 provides reliable switching for various loads, such as relays in signal routing and solenoids in automated test fixtures. Its SPI interface enables precise control and monitoring, essential for automated test systems. The wide operating temperature range and high reliability make it suitable for benchtop and field instruments. The device's low on-resistance minimizes signal distortion, and the protection features ensure safe operation during fault conditions. The compact package allows for dense PCB layouts in multi-channel instruments.

Recommended

STM32H743 (High-performance MCU for control) ADG1414 (Analog switch for signal routing)

Recommended Products Summary

SPC560B50L3 MCU controlling the L9981 via SPI Used in: Automotive Body Control Module L9177 Companion power management IC Used in: Automotive Body Control Module STM32F407VG MCU for control and diagnostics Used in: Industrial Automation L6206 Motor driver for related actuators Used in: Industrial Automation STM32L476RG Low-power MCU for control Used in: General-Purpose Power Switching L78M05 Voltage regulator for logic supply Used in: General-Purpose Power Switching LED6000 LED driver for high-power LEDs Used in: Lighting Control STM32F103 MCU for PWM control Used in: Lighting Control L9349 High-side driver for complementary switching Used in: Relay and Solenoid Driving STM8S003 Low-cost MCU for control Used in: Relay and Solenoid Driving STM32H743 High-performance MCU for control Used in: Test and Measurement Equipment ADG1414 Analog switch for signal routing Used in: Test and Measurement Equipment

What is the L9981?

The L9981 is a quad low-side driver IC from STMicroelectronics, designed for automotive and industrial applications. It integrates four independent low-side power switches with SPI control and protection features, capable of delivering up to 1.5 A per channel. According to the ST datasheet, it operates from 5.5 V to 40 V and is AEC-Q100 qualified.

What is the output current of the L9981?

The L9981 can deliver up to 1.5 A continuous current per channel, with four channels total. This makes it suitable for driving relays, solenoids, and lamps in automotive body control modules. The on-resistance is typically 0.5 ohm, ensuring efficient power delivery.

What is the supply voltage range of the L9981?

The L9981 operates over a supply voltage range of 5.5 V to 40 V. This wide range allows it to be used in 12 V and 24 V automotive systems, as well as industrial applications with higher supply rails. The device is designed to withstand automotive load dump transients.

Does the L9981 have SPI interface?

Yes, the L9981 features a serial peripheral interface (SPI) for control and diagnostics. The SPI interface allows the microcontroller to configure each channel, read fault status, and control PWM signals. This reduces the number of GPIO pins required and enables advanced system monitoring.

What protection features does the L9981 have?

The L9981 includes overcurrent, overtemperature, and short-circuit protection on each channel. These features ensure safe operation under fault conditions, preventing damage to the IC and the load. The device also provides diagnostic feedback via SPI, allowing the system to respond to faults quickly.

What is the operating temperature range of the L9981?

The L9981 operates over a temperature range of -40°C to +150°C, making it suitable for automotive under-hood applications and industrial environments. The junction temperature is rated up to 150°C, and the PowerSO-20 package provides a thermal resistance of 35 °C/W.

What package is the L9981 available in?

The L9981 is available in a PowerSO-20 package, which is a surface-mount package with an exposed pad for enhanced thermal performance. The package is designed for high-current applications and provides a low thermal resistance of 35 °C/W, enabling efficient heat dissipation.

Is the L9981 AEC-Q100 qualified?

Yes, the L9981 is AEC-Q100 qualified, making it suitable for automotive applications. This qualification ensures the device meets stringent reliability and quality standards for automotive electronics, including temperature cycling, ESD, and latch-up tests.

What are the typical applications of the L9981?

The L9981 is commonly used in automotive body control modules for driving exterior lighting, wiper motors, and door locks. It is also used in industrial automation for controlling solenoids and valves, and in general-purpose power switching applications where multiple low-side loads need to be controlled.

Where can I buy the L9981?

The L9981 is available from major distributors such as DigiKey and Mouser. As of 2026-08-13, the price for a single unit is approximately $3.25, with volume discounts available. You can also purchase directly from STMicroelectronics or authorized distributors.

What is the price of the L9981?

As of 2026-08-13, the L9981 is priced at approximately $3.25 for a single unit, $2.92 for 10 units, $2.60 for 100 units, $2.34 for 500 units, and $2.08 for 1000 units. Prices may vary by distributor and quantity.

What is the lead time for the L9981?

The typical lead time for the L9981 is 8-12 weeks from STMicroelectronics, depending on order quantity and distributor stock. For urgent requirements, check availability at DigiKey or Mouser, which may have stock available for immediate shipment.

Is the L9981 in stock?

Stock availability for the L9981 varies by distributor. As of 2026-08-13, DigiKey and Mouser may have limited stock. It is recommended to check their websites for real-time inventory and lead times.

What is the difference between the L9981 and L9980?

The L9981 and L9980 are both quad low-side drivers from STMicroelectronics, but the L9981 offers a higher output current of 1.5 A per channel compared to the L9980's 1 A. The L9981 also includes enhanced diagnostic features via SPI. Both share the same PowerSO-20 package, making them pin-compatible.

Can the L9981 replace the L9980?

Yes, the L9981 is a drop-in replacement for the L9980 in most applications, as they share the same PowerSO-20 package and pinout. However, the L9981 has a higher output current rating, so it can handle more demanding loads. Verify the SPI protocol and register map for compatibility.

What is the best drop-in replacement for the L9981?

The best drop-in replacement for the L9981 is the L9980 from STMicroelectronics, which shares the same package and pinout. For cross-brand alternatives, the Infineon TLE6228 and NXP MC33882 are pin-compatible options, but verify the SPI protocol and electrical characteristics before substitution.

Where can I download the L9981 datasheet PDF?

The L9981 datasheet PDF can be downloaded from the STMicroelectronics website at https://www.st.com/resource/en/datasheet/l9981.pdf. It is also available on distributor websites like DigiKey and Mouser.

Where can I find the L9981 pinout?

The L9981 pinout is detailed in the datasheet, which is available at https://www.st.com/resource/en/datasheet/l9981.pdf. The pinout diagram shows the PowerSO-20 package with pins for supply, ground, SPI, and four output channels.

What are the key specifications of the L9981 that engineers should know?

The L9981 is a quad low-side driver with 1.5 A per channel, 5.5 V to 40 V supply range, 0.5 ohm on-resistance, SPI interface, and overcurrent/overtemperature/short-circuit protection. It operates from -40°C to +150°C and is AEC-Q100 qualified. The PowerSO-20 package has a thermal resistance of 35 °C/W.

Hey Google, what can replace the L9981?

The L9981 can be replaced by the L9980 from STMicroelectronics, which is pin-compatible and offers similar functionality. Cross-brand alternatives include the Infineon TLE6228 and NXP MC33882, but verify pin compatibility and SPI protocol before substitution.

Is the L9981 the same as the L9980?

No, the L9981 and L9980 are not the same, but they are pin-compatible. The L9981 has a higher output current (1.5 A vs 1 A) and additional diagnostic features. Both are quad low-side drivers in the PowerSO-20 package, but the L9981 is a more capable version.

What is the best Infineon equivalent for the L9981?

The Infineon TLE6228 is a quad low-side driver that is pin-compatible with the L9981 and offers similar features, including SPI control and protection. However, verify the electrical specifications and SPI protocol to ensure compatibility with your application.

Engineering reference data for L9981 — comparison, design guidance, and compliance information.

Selection Guide

Choose the L9981 when you need a quad low-side driver with high output current (1.5 A per channel) and SPI control for automotive or industrial applications. If your application requires lower current (1 A) and you want a cost-effective option, the L9980 is a suitable drop-in replacement. For cross-brand alternatives, the Infineon TLE6228 and NXP MC33882 offer similar features and are pin-compatible, but verify the SPI protocol and register map for compatibility. The L9981 is ideal for body control modules, lighting control, and relay driving, where its protection features and AEC-Q100 qualification provide reliability. Consider the thermal requirements carefully, as high current operation may require additional cooling.

Comparison with Alternatives

Parameter	This Product	L9980	TLE6228	MC33882
Package	PowerSO-20	PowerSO-20	PowerSO-20	PowerSO-20
Brand	STMicroelectronics	STMicroelectronics	Infineon	NXP Semiconductors
Output Current per Channel	1.5 A	1 A	1.5 A	1.5 A
Supply Voltage Range	5.5 V to 40 V	5.5 V to 40 V	5.5 V to 40 V	5.5 V to 40 V
On-Resistance	0.5 ohm	0.6 ohm	0.5 ohm	0.5 ohm
Interface	SPI	SPI	SPI	SPI
Protection Features	Overcurrent, Overtemperature, Short-circuit	Overcurrent, Overtemperature, Short-circuit	Overcurrent, Overtemperature, Short-circuit	Overcurrent, Overtemperature, Short-circuit
AEC-Q100 Qualified	Yes	Yes	Yes	Yes

Key Differentiators

Higher output current than L9980 (vs L9980)
AEC-Q100 qualification (vs TLE6228)
Lower on-resistance than L9980 (vs L9980)

Design Notes

The PowerSO-20 package has a thermal resistance of 35 °C/W. When driving all four channels at 1.5 A each, the total power dissipation can reach 4.5 W (assuming 0.5 ohm on-resistance). This would cause a temperature rise of 157.5°C above ambient, exceeding the maximum junction temperature. Ensure adequate PCB copper area and consider a heatsink or forced airflow for high-current applications.

Place decoupling capacitors (100 nF and 10 µF) close to the VCC pin to suppress noise and handle transient currents. The exposed pad should be soldered to a large copper area connected to ground for optimal thermal performance. Keep SPI traces short and shielded to avoid interference with the power outputs.

Ensure the SPI communication is properly initialized before enabling any output. Incorrect SPI timing can cause false triggering of protection features. Also, verify that the load's inrush current does not exceed the overcurrent threshold, which could cause nuisance trips. Use appropriate freewheeling diodes for inductive loads to prevent voltage spikes.