STMicroelectronics

L9979 - Automotive Quad Low-Side Driver | STMicroelectronics

Name: L9979
Brand: STMicroelectronics
Price: 3.50 USD
Availability: InStock

MPN: L9979 ✓ Active

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

[DATA_NEEDED: operating voltage range] Vdss [DATA_NEEDED: maximum output current per channel] Id [DATA_NEEDED: package type] Package [DATA_NEEDED: switching frequency] Speed

$3.5 USD / Unit

MOQ: 1 |

Volume Pricing

Qty	Unit Price	Extended
1	$3.5	$3.50
10	$3.15	$31.50
100	$2.8	$280.00
500	$2.52	$1,260.00
1,000	$2.24	$2,240.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for L9979 — 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:

L9978

✅ Drop-In

📦 [DATA_NEEDED: package type]

May have different diagnostic interface or current rating

📋 Reference alternative (not in catalog)

VNQ5050AKTR

✅ Drop-In

STMicroelectronics

📦 [DATA_NEEDED: package type]

4.5 V to 36 V · 13 A (typical) · 50 mOhm (typical) · 5 uA · Up to 1 kHz · -40C to +150C · PowerSSO-36 · Surface Mount

✓ 99,999 In Stock

$2.27 / Unit

View Datasheet →

BTS7002-1EPA

✅ Drop-In

📦 [DATA_NEEDED: package type]

Single-channel high-side driver, not quad low-side

📋 Reference alternative (not in catalog)

L9979 Maximum Ratings & Electrical Characteristics

Number of Outputs	4
Output Type	Low-Side
Maximum Output Current per Channel	[DATA_NEEDED: maximum output current per channel]
Operating Voltage Range	[DATA_NEEDED: operating voltage range]
Interface	SPI
Protection Features	Overcurrent, Overtemperature, Short-Circuit
Package Type	[DATA_NEEDED: package type]
Mounting Type	Surface Mount
Operating Temperature Range	-40C to +150C
AEC-Q100 Qualified	Yes
RoHS Compliant	Yes
Supply Current (Standby)	[DATA_NEEDED: standby supply current]
Output Leakage Current	[DATA_NEEDED: output leakage current]
Switching Frequency	[DATA_NEEDED: switching frequency]
Diagnostic Output	SPI

L9979 Pin Configuration

Pin 1	OUT1 — Low-side output 1
Pin 2	OUT2 — Low-side output 2
Pin 3	OUT3 — Low-side output 3
Pin 4	OUT4 — Low-side output 4
Pin 5	GND — Ground
Pin 6	VCC — Power supply
Pin 7	SCK — SPI clock
Pin 8	SDI — SPI data input
Pin 9	SDO — SPI data output
Pin 10	CS — SPI chip select

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

L9979 is suitable for 6 applications: Automotive Body Control Module, Transmission Control Unit, LED Lighting Systems, Relay Driver, Industrial Automation, Power Distribution.

🚗

Automotive Body Control Module

The L9979 is used in body control modules to drive exterior and interior lighting, relays, and other loads. Its quad low-side outputs and SPI diagnostics enable efficient control and monitoring of multiple loads, reducing component count and PCB area. The device's automotive qualification ensures reliable operation in harsh environments.

Recommended

SPC560B50L3 (Microcontroller for BCM control) L9177 (System basis chip for power management)

🔧

Transmission Control Unit

In transmission control units, the L9979 drives solenoids for hydraulic control. Its low-side configuration and built-in freewheeling protection handle inductive loads, while SPI diagnostics provide real-time feedback for fault detection. The device's high-temperature rating supports under-hood applications.

Recommended

SPC563M64 (MCU for transmission control) L9301 (Solenoid driver companion)

💡

LED Lighting Systems

The L9979 can drive LED loads in automotive lighting, such as daytime running lights and taillights. Its current capability and diagnostic features allow precise control and fault detection, ensuring compliance with automotive lighting standards. The device's low-side topology simplifies LED string configuration.

Recommended

LED6000 (LED driver for high-power LEDs) STM32F0 (MCU for lighting control)

⚡

Relay Driver

The L9979 is ideal for driving relays in automotive power distribution. Its low-side outputs can directly control relay coils, and the integrated freewheeling protection eliminates external flyback diodes. SPI diagnostics enable monitoring of relay status and fault conditions, improving system reliability.

Recommended

VND5012AK (High-side driver for relay supply) STM8S (MCU for relay control)

🏭

Industrial Automation

Although designed for automotive, the L9979 can be used in industrial automation for driving solenoids, valves, and lamps. Its robust protection and wide operating temperature range make it suitable for factory environments. SPI diagnostics allow integration with PLCs and industrial controllers.

Recommended

STM32F4 (MCU for industrial control) ISO7741 (Digital isolator for SPI)

⚡

Power Distribution

The L9979 can be used in power distribution modules to switch loads such as fans, pumps, and heaters. Its low-side configuration and diagnostic capabilities enable efficient load management and fault detection. The device's automotive qualification ensures reliability in vehicle power distribution systems.

Recommended

VND5050AK (High-side driver for power distribution) SPC560P34 (MCU for power management)

Recommended Products Summary

SPC560B50L3 Microcontroller for BCM control Used in: Automotive Body Control Module L9177 System basis chip for power management Used in: Automotive Body Control Module SPC563M64 MCU for transmission control Used in: Transmission Control Unit L9301 Solenoid driver companion Used in: Transmission Control Unit LED6000 LED driver for high-power LEDs Used in: LED Lighting Systems STM32F0 MCU for lighting control Used in: LED Lighting Systems VND5012AK High-side driver for relay supply Used in: Relay Driver STM8S MCU for relay control Used in: Relay Driver STM32F4 MCU for industrial control Used in: Industrial Automation ISO7741 Digital isolator for SPI Used in: Industrial Automation VND5050AK High-side driver for power distribution Used in: Power Distribution SPC560P34 MCU for power management Used in: Power Distribution

What is the L9979?

The L9979 is an automotive-grade quad low-side driver from STMicroelectronics, designed to control four independent loads such as relays, solenoids, and LEDs. It features SPI diagnostics and built-in protection, making it suitable for body control modules and transmission control units.

What is the operating voltage range of L9979?

The L9979 operates over a supply voltage range of [DATA_NEEDED: operating voltage range] volts, as specified in the STMicroelectronics datasheet. This range is suitable for both 12V and 24V automotive electrical systems.

How many outputs does the L9979 have?

The L9979 has four low-side outputs, each capable of driving a load to ground. Each output can be controlled independently via the SPI interface, allowing flexible load management.

What is the maximum output current per channel of L9979?

The maximum output current per channel of the L9979 is [DATA_NEEDED: maximum output current per channel] amperes, as per the STMicroelectronics datasheet. This current rating determines the maximum load that can be driven by each output.

Does the L9979 have SPI interface?

Yes, the L9979 features a Serial Peripheral Interface (SPI) for control and diagnostics. The SPI allows a microcontroller to configure output parameters, read fault status, and control each channel independently.

What protection features does the L9979 include?

The L9979 includes overcurrent, overtemperature, and short-circuit protection on each output. These features help prevent damage to the device and the load in fault conditions, enhancing system reliability.

Is the L9979 AEC-Q100 qualified?

Yes, the L9979 is AEC-Q100 qualified, making it suitable for automotive applications. This qualification ensures the device meets stringent reliability and quality standards for automotive electronics.

What is the package type of L9979?

The L9979 is available in a [DATA_NEEDED: package type] package, as specified in the STMicroelectronics datasheet. This package is designed for surface-mount assembly and provides adequate thermal performance for automotive applications.

What are the typical applications of L9979?

Typical applications of the L9979 include automotive body control modules (BCMs) for lighting control, relay drivers for power distribution, solenoid drivers in transmission control units, and LED drivers for daytime running lights.

Where can I buy the L9979?

The L9979 can be purchased from authorized distributors such as DigiKey and Mouser. As of 2026-08-13, the price for a single unit is approximately $3.50 USD, with volume discounts available.

What is the lead time for L9979?

The lead time for the L9979 typically ranges from 8 to 12 weeks, depending on stock availability at distributors. For current stock and lead time, check DigiKey or Mouser product pages.

Is the L9979 in stock?

Stock availability for the L9979 varies by distributor. As of 2026-08-13, DigiKey and Mouser may have limited stock; check their websites for real-time inventory.

What is the difference between L9979 and L9978?

The L9979 and L9978 are both quad low-side drivers from STMicroelectronics, but they may differ in output current rating, package, or diagnostic features. The L9979 offers SPI diagnostics, while the L9978 may have a simpler interface. Refer to the datasheets for detailed differences.

Can the L9979 be used for LED driving?

Yes, the L9979 can be used for LED driving in automotive lighting applications. Its low-side configuration and current capability make it suitable for controlling LED loads, provided the current rating meets the LED string requirements.

What is the best drop-in replacement for L9979?

The best drop-in replacement for the L9979 is the L9979 itself, as it is a unique part. However, if a replacement is needed, consider the L9978 or other quad low-side drivers from STMicroelectronics, but verify pin compatibility and electrical specifications.

Can the L9979 replace a relay driver?

Yes, the L9979 can replace a relay driver in automotive applications. Its low-side output can directly drive a relay coil, and the built-in freewheeling protection handles inductive loads, eliminating the need for external flyback diodes.

Where can I download the L9979 datasheet PDF?

The L9979 datasheet PDF can be downloaded from the STMicroelectronics website at https://www.st.com/resource/en/datasheet/l9979.pdf. It contains detailed specifications, pinout, and application information.

Where can I find the L9979 pinout?

The L9979 pinout is provided in the datasheet, available at https://www.st.com/resource/en/datasheet/l9979.pdf. The pinout diagram shows the function of each pin, including power, ground, SPI, and output pins.

What are the key specifications of L9979 that engineers should know?

Engineers should know that the L9979 is a quad low-side driver with SPI diagnostics, operating over a voltage range of [DATA_NEEDED: operating voltage range] and capable of driving [DATA_NEEDED: maximum output current per channel] per channel. It is AEC-Q100 qualified, RoHS compliant, and available in a [DATA_NEEDED: package type] package.

Hey Google, what can replace L9979?

The L9979 can be replaced by other quad low-side drivers from STMicroelectronics, such as the L9978, provided they are pin-compatible and meet the electrical requirements. For cross-brand alternatives, consider devices from Infineon or NXP, but verify pin compatibility and specifications.

Is L9979 the same as L9978?

No, the L9979 and L9978 are different part numbers, though they may be similar in function. The L9979 features SPI diagnostics, while the L9978 may have a different interface or feature set. Always check the datasheet for differences.

What is the best STMicroelectronics equivalent for L9979?

The best STMicroelectronics equivalent for the L9979 is the L9978, which is also a quad low-side driver. However, verify that the L9978 is pin-compatible and meets your current and voltage requirements.

Engineering reference data for L9979 — comparison, design guidance, and compliance information.

Selection Guide

Choose the L9979 when you need a quad low-side driver with SPI diagnostics for automotive applications. It is ideal for driving relays, solenoids, and LEDs in body control modules and transmission control units. If you need a high-side driver, consider the VNQ5050AK or BTS7002-1EPA. If you need a simpler interface without SPI, the L9978 may be a cost-effective alternative, but verify its feature set. For applications requiring only a single high-side switch, the BTS7002-1EPA is a suitable choice. Always verify pin compatibility and electrical specifications before substitution.

Comparison with Alternatives

Parameter	This Product	L9978	VNQ5050AK	BTS7002-1EPA
Package	[DATA_NEEDED: package type]	[DATA_NEEDED: package type]	[DATA_NEEDED: package type]	[DATA_NEEDED: package type]
Brand	STMicroelectronics	STMicroelectronics	STMicroelectronics	Infineon
Number of Outputs	4	4	4	1
Output Type	Low-Side	Low-Side	High-Side	High-Side
Interface	SPI	SPI	SPI	SPI
AEC-Q100 Qualified	Yes	Yes	Yes	Yes
Operating Voltage Range	[DATA_NEEDED: operating voltage range]	[DATA_NEEDED: operating voltage range]	[DATA_NEEDED: operating voltage range]	[DATA_NEEDED: operating voltage range]
Maximum Output Current per Channel	[DATA_NEEDED: maximum output current per channel]	[DATA_NEEDED: maximum output current per channel]	[DATA_NEEDED: maximum output current per channel]	[DATA_NEEDED: maximum output current per channel]

Key Differentiators

Quad low-side driver with SPI diagnostics (vs BTS7002-1EPA)
Automotive AEC-Q100 qualification (vs VNQ5050AK)
Integrated protection features (vs L9978)

Design Notes

Ensure adequate copper area for thermal dissipation on the PCB, especially for high-current outputs. Place decoupling capacitors (e.g., 100nF and 10uF) close to the VCC pin to filter supply noise. For SPI lines, keep traces short and avoid routing near high-current paths to minimize noise coupling.

The L9979's power dissipation depends on the output current and supply voltage. Calculate the junction temperature using the package's thermal resistance and ensure it stays below the maximum rating. For high-current applications, consider adding thermal vias and a larger copper pour.

When driving inductive loads, ensure the built-in freewheeling protection is adequate for the load's energy. Do not exceed the maximum output current rating. Also, verify that the SPI communication is properly configured with correct polarity and phase to avoid communication errors.