L9971-TR - Automotive Quad Low-Side Driver | STMicroelectronics
MPN: L9971-TR ✓ Active| 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 |
L9971-TR Overview
A low-side driver is a type of power switch that connects the load to ground when activated, allowing the load to be powered from a positive supply rail. In automotive systems, low-side drivers are commonly used to control actuators, lamps, and motors, where the load is connected between the battery positive terminal and the driver output. The L9971-TR belongs to the family of smart power switches, which integrate protection and diagnostic features to enhance system reliability.
Key features of the L9971-TR include four independent output channels, each capable of delivering continuous output current up to A, with a maximum supply voltage of V. The device incorporates overcurrent protection, thermal shutdown, and undervoltage lockout to safeguard against fault conditions. Additionally, it features a serial peripheral interface (SPI) for advanced diagnostics and control, enabling real-time monitoring of output status and fault detection.
The L9971-TR is built using STMicroelectronics' advanced BCD (Bipolar-CMOS-DMOS) technology, which combines high-voltage capability with low power consumption and fast switching performance. This technology ensures efficient operation and robust performance in harsh automotive environments, with an operating temperature range of -40°C to +150°C. The device is AEC-Q100 qualified, meeting the stringent quality and reliability standards required for automotive applications.
Typical applications include automotive body control modules, lighting control, relay and solenoid drivers, and industrial automation systems. In automotive body control, the L9971-TR can drive exterior and interior lighting, power windows, and door locks, providing reliable switching with diagnostic feedback. In industrial settings, it can control valves, actuators, and small motors, offering protection and monitoring capabilities.
When designing with the L9971-TR, it is essential to consider proper thermal management, as high output currents can generate significant heat. The exposed pad of the package should be soldered to a large copper area on the PCB to enhance heat dissipation. Additionally, appropriate decoupling capacitors should be placed near the supply pins to minimize voltage transients and ensure stable operation.
Drop-in alternatives for L9971-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 L9971-TR (same form factor and footprint) — differing in Output Type, Protection Features.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
L9971
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.88 / Unit
View Datasheet →L9971-TR-Q1
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
VNQ7004SY
⚡ Same Package ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
L9971-TR Maximum Ratings & Electrical Characteristics
| Number of Channels | 4 |
| Output Type | Low-Side |
| Interface | SPI |
| Protection Features | Overcurrent, Thermal Shutdown, Undervoltage Lockout |
| Operating Temperature Range | -40°C to +150°C |
| Mounting Type | Surface Mount |
| Qualification | AEC-Q100 |
| RoHS Status | Compliant |
| Technology | BCD (Bipolar-CMOS-DMOS) |
L9971-TR Pin Configuration
| Pin 1 | OUT1 — Low-side driver output channel 1 |
| Pin 2 | OUT2 — Low-side driver output channel 2 |
| Pin 3 | OUT3 — Low-side driver output channel 3 |
| Pin 4 | OUT4 — Low-side driver output channel 4 |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Supply voltage |
| Pin 7 | SCK — SPI clock input |
| Pin 8 | SDI — SPI data input |
| Pin 9 | SDO — SPI data output |
| Pin 10 | CS — SPI chip select |
Typical Applications
L9971-TR is suitable for 6 applications: Automotive Body Control Module, Lighting Control, Relay and Solenoid Driver, Industrial Automation, LED Matrix Display, Power Distribution.
Automotive Body Control Module
The L9971-TR is ideal for automotive body control modules (BCMs) where multiple low-side loads such as relays, solenoids, and lamps need to be controlled. Its four independent channels allow driving exterior and interior lighting, power windows, and door locks. The SPI interface enables diagnostic feedback, allowing the BCM to monitor load status and detect faults. The AEC-Q100 qualification ensures reliability in harsh automotive environments, with an operating temperature range of -40°C to +150°C. The device's overcurrent and thermal shutdown protection prevent damage during fault conditions, enhancing system safety.
Recommended
Lighting Control
The L9971-TR can be used for automotive and industrial lighting control, driving LED arrays or incandescent lamps. Its low-side configuration allows direct connection to the load, with the SPI interface providing precise PWM dimming control. The device's high switching frequency capability enables flicker-free dimming, while the overcurrent protection safeguards against LED short circuits. The wide operating temperature range makes it suitable for exterior lighting applications exposed to extreme temperatures.
Recommended
Relay and Solenoid Driver
The L9971-TR is well-suited for driving relays and solenoids in automotive and industrial systems. Its low-side configuration is ideal for switching inductive loads, with built-in freewheeling protection to handle back-EMF. The SPI interface allows individual control of each channel, enabling complex actuation sequences. The device's thermal shutdown protection prevents overheating during prolonged activation, ensuring reliable operation in demanding applications.
Recommended
Industrial Automation
In industrial automation, the L9971-TR can control valves, actuators, and small motors. Its robust design, with overcurrent and thermal protection, ensures reliable operation in harsh factory environments. The SPI interface enables integration with PLCs and industrial controllers, providing real-time diagnostics. The wide supply voltage range allows operation from various industrial power rails, and the AEC-Q100 qualification ensures long-term reliability.
Recommended
LED Matrix Display
The L9971-TR can be used to drive LED matrix displays, where each channel controls a row or column of LEDs. The SPI interface allows efficient multiplexing and PWM dimming, enabling dynamic display patterns. The device's high current capability and thermal management features support large LED arrays. The low-side configuration simplifies the circuit design, as the LEDs are connected between the supply and the driver output.
Recommended
Power Distribution
The L9971-TR can be used in power distribution systems to switch power to various loads. Its four channels allow independent control of multiple loads, with diagnostic feedback for fault detection. The device's protection features prevent damage from overcurrent and thermal events, ensuring system reliability. The SPI interface enables centralized control and monitoring, making it suitable for smart power distribution units.
Recommended
Recommended Products Summary
Engineering reference data for L9971-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9971 | L9971-TR-Q1 | VNQ7004SY |
|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Number of Channels | 4 | 4 | 4 | 4 |
| Output Type | Low-Side | Low-Side | Low-Side | High-Side |
| Interface | SPI | SPI | SPI | SPI |
| Qualification | AEC-Q100 | AEC-Q100 | AEC-Q100 | AEC-Q100 |
| Operating Temperature Range | -40°C to +150°C | -40°C to +150°C | -40°C to +150°C | -40°C to +150°C |
| RoHS Status | Compliant | Compliant | Compliant | Compliant |
Key Differentiators
- Quad low-side driver with SPI diagnostics (vs VNQ7004SY)
- AEC-Q100 qualified (vs L9971)
- Tape-and-reel packaging (vs L9971)
Design Notes
The L9971-TR can dissipate significant power when driving high currents. Ensure the exposed pad is soldered to a large copper area on the PCB to enhance heat dissipation. For continuous operation at maximum current, consider adding thermal vias to improve thermal conductivity to other layers.
Place decoupling capacitors (e.g., 100nF and 10uF) close to the VCC pin to filter high-frequency noise and provide stable supply voltage. Keep the SPI lines short and avoid routing them near high-current traces to minimize electromagnetic interference.
When driving inductive loads, ensure proper freewheeling protection is implemented. The L9971-TR includes internal protection, but external flyback diodes may be required for large inductances. Also, verify the supply voltage does not exceed the absolute maximum rating to prevent damage.
Compliance Information
RoHS compliant per STMicroelectronics product page. AEC-Q100 qualified for automotive applications.