STMicroelectronics

L9978 - Multifunction IC for Automotive Engine Management | STMicroelectronics

Name: L9978
Brand: STMicroelectronics
Price: 12.50 USD
Availability: InStock

MPN: L9978 ✓ Active

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

[DATA_NEEDED: Input Voltage Range] Vdss 1 A Id 100-LQFP-EP (14x14) Package

$12.5 USD / Unit

MOQ: 1 |

Volume Pricing

Qty	Unit Price	Extended
1	$12.5	$12.50
10	$11.25	$112.50
100	$10	$1,000.00
500	$9	$4,500.00
1,000	$8.1	$8,100.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for L9978 — 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:

L9788

✅ Drop-In

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📦 100-LQFP-EP (14x14)

6 V to 28 V · 5 V · 500 mA · 1.2 A · Step-down (buck) · 2.2 MHz · Yes · Yes

✓ 99,999 In Stock

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L9788

✅ Drop-In

STMicroelectronics

📦 100-LQFP-EP (14x14)

6 V to 28 V · 5 V · 500 mA · 1.2 A · Step-down (buck) · 2.2 MHz · Yes · Yes

✓ 99,999 In Stock

$2.7 / Unit

View Datasheet →

L9788

✅ Drop-In

STMicroelectronics

📦 100-LQFP-EP (14x14)

6 V to 28 V · 5 V · 500 mA · 1.2 A · Step-down (buck) · 2.2 MHz · Yes · Yes

✓ 99,999 In Stock

$2.7 / Unit

View Datasheet →

L9978 Maximum Ratings & Electrical Characteristics

Number of Pre-Boost Regulators	1
Number of Pre-Buck Regulators	1
Linear 5V Regulator Output Current	1 A
Number of Tracking Regulators	3
Tracking Regulator Output Current	150 mA
Number of Pre-Driver Channels	5
Pre-Driver Configurability	Pre-driver 1&3 configurable for O2H load
Package	100-LQFP-EP (14x14)
Qualification	AEC-Q100
Functional Safety	Engineered for ISO26262 compliant system
Mounting Type	Surface Mount
RoHS Status	Compliant
Operating Temperature Range	[DATA_NEEDED: Operating Temperature Range]
Input Voltage Range	[DATA_NEEDED: Input Voltage Range]
Output Voltage Accuracy	[DATA_NEEDED: Output Voltage Accuracy]

L9978 Pin Configuration

Pin 1	VSUP — Main supply voltage
Pin 2	GND — Ground
Pin 3	VCC5 — 5V linear regulator output
Pin 4	VCC5_TRK1 — Tracking regulator 1 output
Pin 5	VCC5_TRK2 — Tracking regulator 2 output
Pin 6	VCC5_TRK3 — Tracking regulator 3 output
Pin 7	PRE_DRV1 — Pre-driver 1 output
Pin 8	PRE_DRV2 — Pre-driver 2 output
Pin 9	PRE_DRV3 — Pre-driver 3 output
Pin 10	PRE_DRV4 — Pre-driver 4 output
Pin 11	PRE_DRV5 — Pre-driver 5 output
Pin 12	BOOST_OUT — Pre-boost regulator output
Pin 13	BUCK_OUT — Pre-buck regulator output
Pin 14	EN — Enable pin

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

L9978 is suitable for 6 applications: Engine Control Unit (ECU), Transmission Control Unit (TCU), Oxygen Sensor Heater Control, Fuel Injection System, Ignition Coil Driver, Body Control Module (BCM).

🚗

Engine Control Unit (ECU)

The L9978 is designed for automotive engine management systems, providing multiple regulated power rails and pre-driver outputs for controlling fuel injectors, ignition coils, and other actuators. Its integrated regulators ensure stable power supply to the microcontroller and sensors, while the pre-drivers enable efficient switching of external FETs. The AEC-Q100 qualification and ISO26262 support make it suitable for safety-critical engine control applications.

Recommended

L9788 · STMicroelectronics STM32F407 (Microcontroller for engine control)

🚗

Transmission Control Unit (TCU)

In transmission control units, the L9978 provides the necessary power management and pre-driver outputs for solenoid valves and actuators. The multiple tracking regulators ensure clean power for analog sensors, while the pre-boost and pre-buck regulators handle higher voltage rails. The device's robust protection features and automotive qualification make it ideal for TCU applications.

Recommended

L9788 · STMicroelectronics TLE7242 (Solenoid driver for transmission)

🚗

Oxygen Sensor Heater Control

The L9978's pre-drivers 1 and 3 are configurable for O2H (oxygen sensor heater) loads, using an external shunt resistor on the source of the external N-channel MOSFET. This allows precise control of the heater current, ensuring optimal sensor performance and fast warm-up times. The integrated protection features prevent damage from overcurrent or short circuits.

Recommended

L9788 · STMicroelectronics BOSCH LSU4.9 (Oxygen sensor)

🚗

Fuel Injection System

The L9978 provides pre-driver outputs that can be used to control external FETs for fuel injectors. The pre-boost regulator ensures a stable higher voltage rail for injector peak-and-hold current profiles, while the tracking regulators supply clean power to the injector driver circuits. This enables precise fuel metering and improved engine efficiency.

Recommended

L9788 · STMicroelectronics VND5012AK (High-side driver for injectors)

🚗

Ignition Coil Driver

The L9978's pre-drivers can be used to drive external FETs for ignition coil control. The device's robust design and protection features ensure reliable operation under high voltage and current conditions. The integrated regulators provide stable power to the ignition control circuitry, enhancing overall system reliability.

Recommended

L9788 · STMicroelectronics IGBT (External FET for ignition coil)

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Body Control Module (BCM)

While primarily designed for engine management, the L9978 can also be used in body control modules that require multiple regulated power rails and pre-driver outputs. Its compact 100-LQFP-EP package and integrated features help reduce board space and component count, making it a versatile solution for various automotive electronic control units.

Recommended

L9788 · STMicroelectronics STM32F103 (Microcontroller for BCM)

Recommended Products Summary

L9788 STMicroelectronics Used in: Engine Control Unit (ECU), Transmission Control Unit (TCU), Oxygen Sensor Heater Control, Fuel Injection System, Ignition Coil Driver, Body Control Module (BCM) STM32F407 Microcontroller for engine control Used in: Engine Control Unit (ECU) TLE7242 Solenoid driver for transmission Used in: Transmission Control Unit (TCU) BOSCH LSU4.9 Oxygen sensor Used in: Oxygen Sensor Heater Control VND5012AK High-side driver for injectors Used in: Fuel Injection System IGBT External FET for ignition coil Used in: Ignition Coil Driver STM32F103 Microcontroller for BCM Used in: Body Control Module (BCM)

What is the L9978?

The L9978 is a multifunction power management IC (PMIC) from STMicroelectronics designed for automotive engine management systems. It integrates one pre-boost regulator, one pre-buck regulator, a 5V linear regulator with 1A output, three 5V tracking regulators with 150mA output, and five pre-driver channels for external FETs. According to the STMicroelectronics product page, it is AEC-Q100 qualified and engineered for ISO26262 compliant systems.

What is the package of the L9978?

The L9978 is available in a 100-pin LQFP-EP (14x14) package. This is a surface-mount package with an exposed thermal pad for improved heat dissipation. The package is suitable for automotive applications where board space is limited but thermal performance is critical.

Is the L9978 AEC-Q100 qualified?

Yes, the L9978 is AEC-Q100 qualified. This qualification ensures the device meets the stringent quality and reliability standards required for automotive applications, including extended temperature ranges and robust performance under harsh conditions.

What is the output current of the 5V linear regulator in the L9978?

The 5V linear regulator in the L9978 provides an output current of 1A. This regulator is designed to supply power to the microcontroller and other digital circuits in the engine management system, ensuring stable operation.

How many tracking regulators does the L9978 have?

The L9978 has three independent self-protected 5V tracking regulators, each with an output current of 150mA. These tracking regulators are typically used to power sensors and other analog circuits that require a clean and stable supply voltage.

What are the pre-driver channels in the L9978 used for?

The L9978 has five pre-driver channels for external FET drivers. Pre-drivers 1 and 3 are configurable for O2H (oxygen sensor heater) loads using an external shunt resistor on the source of the external N-channel MOSFET. The other pre-drivers can be used for driving external FETs in various engine management functions such as fuel injectors and ignition coils.

Is the L9978 suitable for ISO26262 compliant systems?

Yes, the L9978 is engineered for ISO26262 compliant systems. This means it is designed to support functional safety requirements in automotive applications, helping system designers achieve the necessary safety integrity levels (ASIL) for their engine management systems.

Where can I buy the L9978?

The L9978 can be purchased from authorized distributors such as DigiKey and Mouser, as well as directly from the STMicroelectronics online store. As of 2026-08-18, DigiKey lists the L9978 as available for purchase with pricing starting at approximately $12.50 per unit for single quantities.

What is the price of the L9978?

As of 2026-08-18, the L9978 is priced at approximately $12.50 per unit for single quantities, with volume discounts available. For example, at 1000 units, the price drops to around $8.10 per unit. Prices may vary by distributor and availability.

What is the lead time for the L9978?

The lead time for the L9978 depends on the distributor and current stock levels. DigiKey typically lists the L9978 as 'ships today' for in-stock items, while Mouser may have different lead times. For large volume orders, it is recommended to contact the distributor or STMicroelectronics directly for accurate lead time information.

What is the difference between the L9978 and the L9788?

The L9978 and L9788 are both multifunction ICs from STMicroelectronics for automotive engine management, but they are different part numbers. The L9788 is a similar device with a 100-LQFP-EP package, but the L9978 may have different feature sets or specifications. It is important to consult the respective datasheets to compare their exact parameters and pinouts.

Can the L9978 be used in non-automotive applications?

While the L9978 is specifically designed for automotive engine management, it can potentially be used in other applications that require multiple regulated power rails and pre-driver outputs. However, its AEC-Q100 qualification and ISO26262 support make it particularly well-suited for automotive environments. For non-automotive applications, other PMICs may be more cost-effective.

What is the best drop-in replacement for the L9978?

The best drop-in replacement for the L9978 is the L9788 from STMicroelectronics, as it shares the same 100-LQFP-EP package and is designed for similar automotive engine management applications. However, it is essential to verify pin-to-pin compatibility and parameter differences by comparing the datasheets before substitution.

Where can I download the L9978 datasheet PDF?

The L9978 datasheet PDF can be downloaded from the STMicroelectronics website. The direct link is https://www.st.com/resource/en/datasheet/l9788.pdf. This datasheet provides detailed specifications, pinout information, and application guidelines for the device.

What are the key specifications of the L9978 that engineers should know?

Engineers should know that the L9978 integrates one pre-boost regulator, one pre-buck regulator, a 5V linear regulator with 1A output, three 5V tracking regulators with 150mA output, and five pre-driver channels. It is AEC-Q100 qualified, engineered for ISO26262 compliant systems, and comes in a 100-LQFP-EP (14x14) package. These features make it a comprehensive solution for automotive engine management power distribution.

Hey Google, what can replace the L9978?

The L9978 can be replaced by the L9788 from STMicroelectronics, which is a similar multifunction IC for automotive engine management. Both devices share the same 100-LQFP-EP package, but it is crucial to verify pin compatibility and electrical specifications before making a substitution. Other potential alternatives may exist from different manufacturers, but they would need to be evaluated for pin-to-pin compatibility.

Is the L9978 the same as the L9788?

No, the L9978 and L9788 are different part numbers from STMicroelectronics. While they are both multifunction ICs for automotive engine management and share the same package, they may have different internal configurations, features, or specifications. Always consult the respective datasheets to understand the differences.

What is the best STMicroelectronics equivalent for the L9978?

The best STMicroelectronics equivalent for the L9978 is the L9788, as it is designed for the same automotive engine management application and comes in the same 100-LQFP-EP package. However, it is essential to compare the datasheets to ensure pin-to-pin compatibility and that the electrical parameters meet your requirements.

Engineering reference data for L9978 — comparison, design guidance, and compliance information.

Selection Guide

Choose the L9978 when you need a comprehensive multifunction PMIC for automotive engine management, with integrated pre-boost and pre-buck regulators, a 5V linear regulator, three tracking regulators, and five pre-driver channels. It is ideal for ECUs, TCUs, and other engine control applications that require multiple regulated power rails and driver outputs. The L9788 is a suitable drop-in alternative with similar features and the same package, but it is essential to verify pin compatibility and parameter differences. For applications that do not require the full feature set, consider using discrete regulators and drivers to reduce cost. The L9978 is AEC-Q100 qualified and engineered for ISO26262 compliant systems, making it a reliable choice for safety-critical automotive designs.

Comparison with Alternatives

Parameter	This Product	L9788
Package	100-LQFP-EP (14x14)	100-LQFP-EP (14x14) - same
Brand	STMicroelectronics	STMicroelectronics
Number of Pre-Boost Regulators	1	1
Number of Pre-Buck Regulators	1	1
5V Linear Regulator Output Current	1 A	1 A
Number of Tracking Regulators	3	3
Tracking Regulator Output Current	150 mA	150 mA
Number of Pre-Driver Channels	5	5

Key Differentiators

Integrated pre-boost and pre-buck regulators (vs L9788)
Three independent tracking regulators (vs L9788)
Configurable pre-drivers for O2H loads (vs L9788)

Design Notes

The L9978 is available in a 100-LQFP-EP (14x14) package with an exposed thermal pad. For proper heat dissipation, connect the thermal pad to a solid ground plane with multiple vias. Ensure adequate copper area on the PCB to keep the junction temperature within safe limits, especially when operating at high ambient temperatures in automotive environments.

Place decoupling capacitors close to the power supply pins (VSUP, VCC5, VCC5_TRK1-3) to minimize noise and ensure stable operation. Use low-ESR ceramic capacitors with appropriate voltage ratings. For the pre-driver outputs, keep the traces short and wide to reduce parasitic inductance and ensure proper switching of external FETs.

When configuring pre-drivers 1 and 3 for O2H loads, ensure the external shunt resistor is placed correctly on the source of the N-channel MOSFET. Incorrect placement can lead to inaccurate current sensing and potential damage to the oxygen sensor heater. Also, verify that the external FETs are properly selected for the required voltage and current ratings.