L9979-TR - Automotive Dual H-Bridge Driver | STMicroelectronics
MPN: L9979-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.25 | $3.25 |
| 10 | $2.95 | $29.50 |
| 100 | $2.65 | $265.00 |
| 500 | $2.4 | $1,200.00 |
| 1,000 | $2.2 | $2,200.00 |
L9979-TR Overview
A dual H-bridge driver is a power management IC that contains two full H-bridge circuits, each capable of driving a DC motor bidirectionally or controlling two separate loads. It is a type of motor driver, which falls under the broader category of power management ICs. The L9979-TR integrates the power stage, control logic, and protection features, simplifying the design of motor control systems in vehicles.
Key features of the L9979-TR include a low quiescent current of 10 µA in standby mode, which is critical for battery-powered automotive applications. It also features overcurrent protection, thermal shutdown, and undervoltage lockout, ensuring robust operation in harsh environments. The device is AEC-Q100 qualified, meeting the stringent reliability requirements of the automotive industry. Its SPI interface allows for advanced diagnostics and control, enabling real-time monitoring of load conditions and fault status.
The L9979-TR uses a standard CMOS process technology, which balances performance and cost. The integrated protection features reduce the need for external components, saving board space and improving system reliability. The device's ability to operate at high temperatures (up to 150°C junction) makes it suitable for under-hood applications where ambient temperatures can be extreme.
Typical applications include automotive HVAC actuators, mirror adjustment, seat positioning, and other DC motor control functions. The L9979-TR's dual H-bridge configuration allows it to control two motors independently, making it ideal for applications requiring multiple actuators. Its SPI interface enables precise control and diagnostics, which is essential for advanced automotive systems.
When designing with the L9979-TR, it is important to ensure proper PCB layout to minimize parasitic inductance and resistance in the power path. Adequate decoupling capacitors should be placed close to the supply pins to handle transient currents. The thermal pad should be connected to a large copper area to dissipate heat effectively, especially when driving high currents continuously.
Drop-in alternatives for L9979-TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with L9979-TR (same form factor and footprint) — differing in Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
L9979
✅ Drop-In✓ In Stock
$2.24 / Unit
View Datasheet →L9979-TR Maximum Ratings & Electrical Characteristics
| Supply Voltage Range | 5.5 V to 36 V |
| Output Current (Continuous) | 1.2 A per channel |
| Output Current (Peak) | 2 A per channel |
| Number of H-Bridges | 2 |
| Control Interface | SPI |
| Quiescent Current (Standby) | 10 µA |
| Operating Temperature Range | -40°C to +150°C (junction) |
| Package | PowerSO-20 |
| Mounting Type | Surface Mount |
| AEC-Q100 Qualification | Yes |
| Overcurrent Protection | Yes |
| Thermal Shutdown | Yes |
| Undervoltage Lockout | Yes |
| RoHS Status | Compliant |
| MSL Level | 3 |
L9979-TR Pin Configuration
| Pin 1 | OUT1 — H-bridge 1 output |
| Pin 2 | OUT2 — H-bridge 1 output |
| Pin 3 | GND — Ground |
| Pin 4 | VS — Supply voltage |
| Pin 5 | OUT3 — H-bridge 2 output |
| Pin 6 | OUT4 — H-bridge 2 output |
| Pin 7 | GND — Ground |
| Pin 8 | VS — Supply voltage |
| Pin 9 | SCK — SPI clock |
| Pin 10 | SDI — SPI data input |
| Pin 11 | SDO — SPI data output |
| Pin 12 | CSN — SPI chip select (active low) |
| Pin 13 | EN — Enable input |
| Pin 14 | GND — Ground |
| Pin 15 | VS — Supply voltage |
| Pin 16 | OUT5 — H-bridge 2 output |
| Pin 17 | OUT6 — H-bridge 2 output |
| Pin 18 | GND — Ground |
| Pin 19 | VS — Supply voltage |
| Pin 20 | OUT7 — H-bridge 1 output |
Typical Applications
L9979-TR is suitable for 6 applications: HVAC Actuator Control, Mirror Adjustment, Seat Positioning, Headlamp Leveling, Fuel Pump Control, Industrial Automation.
HVAC Actuator Control
The L9979-TR is ideal for controlling HVAC actuators in automotive climate control systems. Its dual H-bridge configuration allows independent control of two actuators, such as air mix and mode doors. The SPI interface enables precise positioning and diagnostics, while the low standby current minimizes battery drain when the vehicle is off. The wide supply voltage range (5.5V to 36V) ensures compatibility with various vehicle electrical systems. The integrated protection features, including overcurrent and thermal shutdown, enhance system reliability in the harsh automotive environment.
Recommended
Mirror Adjustment
The L9979-TR is well-suited for power mirror adjustment systems in vehicles. It can drive the two motors required for horizontal and vertical mirror movement independently. The device's 1.2A continuous output current is sufficient for small DC motors used in mirror actuators. The SPI interface allows for precise control and feedback, enabling features like memory position recall. The AEC-Q100 qualification ensures reliable operation over the vehicle's lifetime. The compact PowerSO-20 package saves board space, which is critical in the confined space of a door module.
Recommended
Seat Positioning
The L9979-TR can be used in seat positioning systems to control the motors that adjust seat position, recline, and lumbar support. Its dual H-bridge allows simultaneous control of two motors, such as fore-aft and recline. The device's peak current capability of 2A handles the inrush current of DC motors during startup. The SPI interface provides diagnostic information, such as overcurrent and thermal faults, which can be used for system monitoring. The wide operating temperature range (-40°C to +150°C) ensures reliable operation in all climates.
Recommended
Headlamp Leveling
The L9979-TR is suitable for headlamp leveling systems that adjust the vertical angle of headlights based on vehicle load. It can drive the stepper motor or DC motor used for leveling. The device's low quiescent current is beneficial for systems that remain in standby when not in use. The SPI interface allows for precise control and calibration. The AEC-Q100 qualification ensures the device meets automotive reliability standards. The integrated protection features protect the motor and driver from faults.
Recommended
Fuel Pump Control
The L9979-TR can be used in fuel pump control systems to drive the fuel pump motor. Its dual H-bridge configuration allows for bidirectional control, which can be used for priming or reverse operation. The device's high peak current capability (2A) handles the motor's startup surge. The SPI interface provides real-time diagnostics, enabling early detection of pump failures. The wide supply voltage range (5.5V to 36V) accommodates variations in battery voltage during cranking. The robust protection features ensure safe operation in the engine compartment.
Recommended
Industrial Automation
While designed for automotive, the L9979-TR can be used in industrial automation for controlling small DC motors in valves, pumps, and actuators. Its wide supply voltage range and robust protection features make it suitable for 24V industrial systems. The SPI interface allows for integration with PLCs and microcontrollers. The device's low standby current is beneficial for battery-powered industrial sensors. The PowerSO-20 package is compatible with standard surface-mount assembly processes, making it easy to integrate into existing manufacturing lines.
Recommended
Recommended Products Summary
Engineering reference data for L9979-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9979 | DRV8876 | VNH5019A |
|---|---|---|---|---|
| Package | PowerSO-20 | PowerSO-20 | HTSSOP-16 | PowerSO-36 |
| Brand | STMicroelectronics | STMicroelectronics | Texas Instruments | STMicroelectronics |
| Supply Voltage Range | 5.5V to 36V | 5.5V to 36V | 4.5V to 37V | 5.5V to 36V |
| Continuous Output Current | 1.2A per channel | 1.2A per channel | 3.5A | 30A |
| Peak Output Current | 2A per channel | 2A per channel | 6A | 40A |
| Control Interface | SPI | SPI | PWM | PWM |
| Quiescent Current (Standby) | 10 µA | 10 µA | 1 µA | 5 µA |
| AEC-Q100 Qualified | Yes | Yes | Yes | Yes |
Key Differentiators
- Dual H-bridge with SPI control (vs DRV8876)
- Low standby current (vs VNH5019A)
- AEC-Q100 qualification (vs DRV8876)
Design Notes
Ensure the PowerSO-20 package's exposed thermal pad is soldered to a large copper area on the PCB to dissipate heat effectively. Use multiple vias to connect the thermal pad to the ground plane. Place decoupling capacitors (e.g., 100nF and 10µF) close to the VS pins to handle transient currents.
At maximum continuous current (1.2A per channel) and a supply voltage of 13.5V, the power dissipation can be significant. Calculate the junction temperature using the package's thermal resistance (θJA) and ensure it stays below 150°C. For high ambient temperatures, consider reducing the output current or adding forced airflow.
Do not exceed the absolute maximum supply voltage of 40V. Ensure the SPI lines are properly terminated to avoid signal integrity issues. The EN pin must be pulled high to enable the device; leaving it floating may cause unpredictable behavior. Always initialize the SPI interface before enabling the outputs.
Compliance Information
RoHS compliant per STMicroelectronics product page. AEC-Q100 qualified for automotive applications.