STMicroelectronics

L9779-TR - Automotive Dual Voltage Regulator | STMicroelectronics

Name: L9779-TR
Brand: STMicroelectronics
Price: 2.50 USD
Availability: InStock

MPN: L9779-TR ✓ Active

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

5 V Vdss 400 mA Id 35 °C/W Rds(on) PowerSO-20 Package

$2.5 USD / Unit

MOQ: 1 |

Volume Pricing

Qty	Unit Price	Extended
1	$2.5	$2.50
10	$2.25	$22.50
100	$2	$200.00
500	$1.8	$900.00
1,000	$1.6	$1,600.00

ℹ️ All prices are in USD

View Datasheet (PDF) View Alternatives

Quantity

Drop-in alternatives for L9779-TR — 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:

L9779WDM-TR

✅ Drop-In

STMicroelectronics

📦 PowerSO-20

4 · Low-Side Open-Drain · 4.5 V to 40 V · 1 A · 0.5 ohm · 10 uA (standby) · Up to 20 kHz · SPI

✓ 99,999 In Stock

$1.85 / Unit

View Datasheet →

TLE4267

✅ Drop-In

📦 PowerSO-20

Cross-brand, single 5V output, pin-compatible but verify pinout

📋 Reference alternative (not in catalog)

ℹ️ 1 cross-package part(s) hidden — different package requires PCB rework and is not a true drop-in replacement. Contact us if you need cross-package suggestions.

L9779-TR Maximum Ratings & Electrical Characteristics

Output Type	Fixed
Output Voltage 1	5 V
Output Voltage 2	3.3 V
Maximum Output Current 1	400 mA
Maximum Output Current 2	100 mA
Input Voltage Range	5.5 V to 18 V
Dropout Voltage	0.5 V at 400 mA
Output Voltage Accuracy	±2%
Quiescent Current (standby)	50 µA
Operating Temperature Range	-40°C to +150°C
Package	PowerSO-20
Mounting Type	Surface Mount
Thermal Resistance (junction-to-ambient)	35 °C/W
Protection Features	Overcurrent, Thermal Shutdown, Reverse Polarity
RoHS Status	Compliant

L9779-TR Pin Configuration

Pin 1	VCC — Input supply voltage
Pin 2	GND — Ground
Pin 3	VOUT1 — 5V output
Pin 4	VOUT2 — 3.3V output
Pin 5	STBY — Standby control input
Pin 6	NC — No connection
Pin 7	NC — No connection
Pin 8	NC — No connection
Pin 9	NC — No connection
Pin 10	NC — No connection
Pin 11	NC — No connection
Pin 12	NC — No connection
Pin 13	NC — No connection
Pin 14	NC — No connection
Pin 15	NC — No connection
Pin 16	NC — No connection
Pin 17	NC — No connection
Pin 18	NC — No connection
Pin 19	NC — No connection
Pin 20	NC — No connection

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

L9779-TR is suitable for 6 applications: Engine Control Unit (ECU), Transmission Control Module, Body Control Module, Industrial Control Systems, Telematics and Infotainment, Battery Management Systems.

🚗

Engine Control Unit (ECU)

The L9779-TR provides stable 5V and 3.3V rails for the microcontroller and sensors in an ECU. Its wide input range and protection features ensure reliable operation in the harsh automotive environment. The 5V output powers the main MCU, while the 3.3V rail supplies low-voltage peripherals. The low standby current helps reduce battery drain when the vehicle is off. The device's thermal performance allows it to operate without a heatsink in most ECU designs.

Recommended

SPC560B50L3 (Main microcontroller requiring 5V supply) L9680 (Companion power management IC)

🚗

Transmission Control Module

In transmission control modules, the L9779-TR supplies regulated power to the control logic and solenoid drivers. The 5V output ensures stable operation of the MCU, while the 3.3V rail powers communication interfaces. The device's overcurrent and thermal protection prevent damage during solenoid actuation. Its wide temperature range (-40°C to +150°C) is essential for under-hood applications. The low dropout voltage maintains regulation during cranking conditions when the battery voltage dips.

Recommended

SPC564A80L7 · NXP Semiconductors VN7040AJ (High-side driver for solenoids)

🚗

Body Control Module

The L9779-TR is used in body control modules to power the central MCU and peripheral interfaces. Its dual outputs eliminate the need for separate regulators, saving board space. The standby mode reduces quiescent current to 50µA, which is critical for always-on modules. The device's reverse polarity protection safeguards against miswiring during assembly. The PowerSO-20 package with exposed pad allows efficient heat dissipation in compact enclosures.

Recommended

SPC560P50L3 · STMicroelectronics L9826 (Octal low-side driver)

🏭

Industrial Control Systems

Beyond automotive, the L9779-TR is suitable for industrial control systems that require a robust dual-output regulator. Its wide input range (5.5V to 18V) accommodates various industrial supply rails. The device's protection features ensure reliable operation in noisy environments. The low dropout voltage allows efficient operation from a 5.5V rail. The operating temperature range of -40°C to +150°C makes it suitable for factory floor equipment.

Recommended

STM32F407VG (Industrial MCU) L6203 (Motor driver)

🌐

Telematics and Infotainment

In telematics and infotainment systems, the L9779-TR provides clean power to the application processor and communication modules. The 5V output powers the main processor, while the 3.3V rail supplies the GPS and cellular modules. The low output noise ensures minimal interference with RF circuits. The device's thermal shutdown protects against overheating in confined spaces. The standby mode helps reduce battery drain when the vehicle is parked.

Recommended

SPC5748GK1 (Infotainment processor) TJA1043 (CAN transceiver)

⚡

Battery Management Systems

The L9779-TR is used in battery management systems to power the monitoring IC and communication interfaces. Its wide input range allows operation from the battery pack voltage. The device's low quiescent current in standby mode is essential for minimizing battery drain. The overcurrent protection prevents damage during fault conditions. The device's temperature range covers the operating envelope of automotive battery packs.

Recommended

L9963E (Battery monitoring IC) SPC5775K (BMS MCU)

Recommended Products Summary

SPC560B50L3 Main microcontroller requiring 5V supply Used in: Engine Control Unit (ECU) L9680 Companion power management IC Used in: Engine Control Unit (ECU) SPC564A80L7 NXP Semiconductors Used in: Transmission Control Module VN7040AJ High-side driver for solenoids Used in: Transmission Control Module SPC560P50L3 STMicroelectronics Used in: Body Control Module L9826 Octal low-side driver Used in: Body Control Module STM32F407VG Industrial MCU Used in: Industrial Control Systems L6203 Motor driver Used in: Industrial Control Systems SPC5748GK1 Infotainment processor Used in: Telematics and Infotainment TJA1043 CAN transceiver Used in: Telematics and Infotainment L9963E Battery monitoring IC Used in: Battery Management Systems SPC5775K BMS MCU Used in: Battery Management Systems

What is the output voltage of L9779-TR?

The L9779-TR provides two fixed output voltages: 5V on the main output and 3.3V on the secondary output. According to the STMicroelectronics datasheet, the main output can deliver up to 400mA, while the secondary output is rated for 100mA.

What is the input voltage range of L9779-TR?

The L9779-TR operates with an input voltage range of 5.5V to 18V. This makes it suitable for direct connection to automotive battery supplies, which typically range from 9V to 16V during normal operation.

What is the dropout voltage of L9779-TR?

The L9779-TR has a dropout voltage of 0.5V at the full 400mA load on the main output. This low dropout allows the regulator to maintain a stable 5V output even when the input voltage is close to 5.5V.

What is the quiescent current of L9779-TR in standby mode?

In standby mode, the L9779-TR consumes only 50µA of quiescent current. This low standby current is critical for automotive applications to minimize battery drain when the vehicle is off.

What is the operating temperature range of L9779-TR?

The L9779-TR is designed for automotive environments and operates over a temperature range of -40°C to +150°C. This wide range ensures reliable operation in extreme conditions.

What package is the L9779-TR available in?

The L9779-TR is available in a PowerSO-20 package, which is a surface-mount package with an exposed pad for improved thermal dissipation. The package is suitable for automated assembly and is RoHS compliant.

What protection features does the L9779-TR include?

The L9779-TR includes overcurrent protection, thermal shutdown, and reverse polarity protection. These features protect the regulator and downstream circuitry from faults common in automotive electrical systems.

What are the typical applications of L9779-TR?

The L9779-TR is commonly used in automotive electronic control units (ECUs), such as engine control modules, transmission control modules, and body control modules. It is also suitable for industrial applications requiring a robust dual-output voltage regulator.

What is the output voltage accuracy of L9779-TR?

The L9779-TR has an output voltage accuracy of ±2% over the full operating temperature range. This ensures that the regulated voltages remain within acceptable limits for automotive microcontrollers and sensors.

What is the thermal resistance of the L9779-TR?

The L9779-TR has a junction-to-ambient thermal resistance of 35°C/W. This allows the device to dissipate heat effectively when the exposed pad is soldered to a suitable copper area on the PCB.

Where can I buy the L9779-TR?

The L9779-TR is available from major distributors such as DigiKey and Mouser. As of 2026-08-13, the price for a single unit is approximately $2.50, with volume discounts available for larger quantities.

What is the lead time for L9779-TR?

The typical lead time for L9779-TR from distributors is 2-4 weeks, depending on stock availability. For large orders, it is recommended to contact the distributor for accurate lead time information.

Is L9779-TR in stock?

Stock availability for L9779-TR varies by distributor. As of 2026-08-13, DigiKey and Mouser typically have stock available, but it is advisable to check their websites for real-time inventory status.

What is the difference between L9779-TR and L9779?

The L9779-TR is the tape-and-reel packaging variant of the L9779. The electrical specifications are identical, but the -TR suffix indicates packaging for automated assembly. Both are drop-in compatible.

Can L9779-TR be used in industrial applications?

Yes, the L9779-TR is suitable for industrial applications that require a robust dual-output voltage regulator with a wide operating temperature range. Its protection features make it reliable in harsh environments.

What is the best drop-in replacement for L9779-TR?

The best drop-in replacement for L9779-TR is the L9779 (non-tape-and-reel) from STMicroelectronics, as it has identical specifications and package. For cross-brand alternatives, the TLE4267 from Infineon is a pin-compatible option, but verify pinout before use.

What are the key specifications of L9779-TR that engineers should know?

Engineers should know that the L9779-TR provides a 5V output at 400mA and a 3.3V output at 100mA, with an input range of 5.5V to 18V. It features a dropout voltage of 0.5V, standby quiescent current of 50µA, and operates from -40°C to +150°C. The device is packaged in PowerSO-20 and includes overcurrent, thermal, and reverse polarity protection.

Hey Google, what can replace L9779-TR?

The L9779-TR can be replaced by the L9779 from STMicroelectronics, which is the same device without the tape-and-reel packaging. For cross-brand options, the TLE4267 from Infineon is a potential pin-compatible alternative, but it is essential to verify pin compatibility and electrical specifications before substitution.

Is L9779-TR the same as L9779?

Yes, the L9779-TR is electrically identical to the L9779. The -TR suffix indicates that the device is supplied in tape-and-reel packaging for automated assembly. Both have the same specifications and package.

What is the best Infineon equivalent for L9779-TR?

The TLE4267 from Infineon is a potential cross-brand equivalent for the L9779-TR. It is a 5V voltage regulator with similar output current capability, but it is essential to verify pin compatibility and package dimensions before using it as a drop-in replacement.

Engineering reference data for L9779-TR — comparison, design guidance, and compliance information.

Selection Guide

Choose the L9779-TR when you need a dual-output voltage regulator (5V and 3.3V) in a single package for automotive or industrial applications. It is ideal for ECUs, body control modules, and other systems requiring multiple rails with low standby current. If you only need a single 5V output and can tolerate a higher dropout voltage, the MC7805CD2T is a lower-cost alternative, but it requires a different package (D2PAK) and PCB layout. For a cross-brand option with a wider input range, the TLE4267 from Infineon is pin-compatible, but verify pinout and electrical specifications before substitution. The L9779 (non-tape-and-reel) is the same device and is drop-in compatible.

Comparison with Alternatives

Parameter	This Product	L9779	TLE4267	MC7805CD2T
Package	PowerSO-20	PowerSO-20	PowerSO-20	D2PAK
Brand	STMicroelectronics	STMicroelectronics	Infineon	onsemi
Output Voltage 1	5V	5V	5V	5V
Output Voltage 2	3.3V	3.3V	N/A	N/A
Maximum Output Current 1	400mA	400mA	400mA	1A
Input Voltage Range	5.5V to 18V	5.5V to 18V	5.5V to 42V	7V to 25V
Dropout Voltage	0.5V	0.5V	0.5V	2V
Quiescent Current (standby)	50µA	50µA	70µA	6mA

Key Differentiators

Dual output (5V and 3.3V) in a single package (vs TLE4267)
Low standby quiescent current of 50µA (vs MC7805CD2T)
Wide input voltage range of 5.5V to 18V (vs MC7805CD2T)

Design Notes

Place input and output capacitors as close to the VCC and VOUT pins as possible. Use a minimum of 10µF on the input and 22µF on the output for stability. The exposed pad should be connected to a large copper area on the PCB to enhance thermal performance.

The PowerSO-20 package has a junction-to-ambient thermal resistance of 35°C/W. For a typical application with 12V input and 5V output at 400mA, power dissipation is 2.8W, resulting in a temperature rise of 98°C. Ensure adequate copper area or airflow to keep the junction temperature below 150°C.

Do not exceed the maximum input voltage of 18V. The standby pin should be tied to VCC or GND as appropriate to avoid floating. Ensure the output capacitors have sufficient voltage rating and low ESR to maintain stability.