L9954-TR - SPI Controlled 8-Channel Low-Side Driver | STMicroelectronics
MPN: L9954-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.5 | $4.50 |
| 10 | $4.05 | $40.50 |
| 100 | $3.6 | $360.00 |
| 500 | $3.24 | $1,620.00 |
| 1,000 | $2.88 | $2,880.00 |
L9954-TR Overview
A low-side driver is a type of power switch that connects the load to ground when activated, allowing the microcontroller to control high-side loads with minimal complexity. In the hierarchy of power management, a low-side driver falls under the category of power switches, which are essential components in automotive body control modules, industrial PLCs, and general-purpose switching applications. The L9954-TR specifically integrates eight such channels in a single package, reducing board space and component count.
Key features of the L9954-TR include an SPI interface with daisy-chain capability, 8-channel low-side outputs with a typical current rating of 1.5 A per channel, and a supply voltage range from 4.5 V to 5.5 V for the logic, with load supply up to 40 V. The device offers a low quiescent current in standby mode, making it suitable for battery-powered automotive systems. It also includes a 16-bit SPI protocol for control and diagnostics, with a maximum SPI clock frequency of 5 MHz.
Technically, the L9954-TR is built on ST's BCD (Bipolar-CMOS-DMOS) technology, which combines the benefits of bipolar analog precision, CMOS digital logic, and DMOS power switching. This allows for high integration and robustness in harsh automotive environments. The device is available in a PowerSO-36 package, which provides excellent thermal performance and is designed for surface-mount assembly. The package includes an exposed pad for enhanced heat dissipation, and the device is qualified to AEC-Q100 standards for automotive applications.
Typical applications include automotive body control modules, where the L9954-TR drives relays for lights, wipers, and door locks; industrial automation for controlling solenoids and valves; and general-purpose switching in test equipment. Its SPI interface simplifies microcontroller integration, and the diagnostic features enable real-time fault monitoring, improving system reliability.
When designing with the L9954-TR, ensure proper thermal management by connecting the exposed pad to a sufficient copper area on the PCB. Additionally, place a 100 nF decoupling capacitor close to the VCC pin and a bulk capacitor on the load supply to handle inrush currents. The SPI lines should be kept short and shielded to minimize noise, especially in automotive environments with high electromagnetic interference.
Drop-in alternatives for L9954-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 L9954-TR (same form factor and footprint) — differing in Operating Temperature, Output Current per Channel, Standby Current.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
L9954
✅ Drop-In✓ In Stock
$5.5 / Unit
View Datasheet →TLE6228GP
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
L9954-TR Maximum Ratings & Electrical Characteristics
| Number of Channels | 8 |
| Output Type | Low-Side |
| Output Current per Channel | 1.5 A (typical) |
| Supply Voltage (Logic) | 4.5 V to 5.5 V |
| Load Supply Voltage | Up to 40 V |
| SPI Interface | Yes, 16-bit, up to 5 MHz |
| Standby Current | 10 uA (typical) |
| Operating Temperature | -40C to +150C |
| Package | PowerSO-36 |
| Mounting Type | Surface Mount |
| AEC-Q100 Qualified | Yes |
| RoHS Compliant | Yes |
| Protection Features | Overcurrent, Overtemperature, Open-Load |
| Diagnostic Output | SPI-based |
| Technology | BCD (Bipolar-CMOS-DMOS) |
L9954-TR Pin Configuration
| Pin 1 | OUT1 — Low-side output channel 1 |
| Pin 2 | OUT2 — Low-side output channel 2 |
| Pin 3 | OUT3 — Low-side output channel 3 |
| Pin 4 | OUT4 — Low-side output channel 4 |
| Pin 5 | OUT5 — Low-side output channel 5 |
| Pin 6 | OUT6 — Low-side output channel 6 |
| Pin 7 | OUT7 — Low-side output channel 7 |
| Pin 8 | OUT8 — Low-side output channel 8 |
| Pin 9 | GND — Ground |
| Pin 10 | VCC — Logic supply voltage (4.5V to 5.5V) |
| Pin 11 | VS — Load supply voltage (up to 40V) |
| Pin 12 | SCK — SPI clock input |
| Pin 13 | SI — SPI data input |
| Pin 14 | SO — SPI data output |
| Pin 15 | CSN — SPI chip select (active low) |
| Pin 16 | RST — Reset input (active low) |
Typical Applications
L9954-TR is suitable for 6 applications: Automotive Body Control Module, Industrial Automation, LED Lighting Control, Relay and Solenoid Driver, Test and Measurement Equipment, General Purpose Switching.
Automotive Body Control Module
The L9954-TR is ideal for automotive body control modules (BCMs) where it drives relays for lights, wipers, and door locks. Its 8 channels and SPI diagnostics enable centralized control and fault monitoring. The device's AEC-Q100 qualification ensures reliability in harsh automotive environments. In a typical BCM, the L9954-TR interfaces with a microcontroller via SPI, controlling low-side loads such as relays and LEDs. The SPI interface allows the MCU to read diagnostic data, including open-load and overcurrent faults, enabling predictive maintenance. The wide supply voltage range (up to 40V load supply) accommodates 12V and 24V systems, and the low standby current (10 uA) helps meet stringent quiescent current requirements in vehicles. Compared to discrete transistor solutions, the L9954-TR reduces component count and PCB area, while providing advanced diagnostics that improve system reliability.
Recommended
Industrial Automation
In industrial automation, the L9954-TR drives solenoids, valves, and actuators in PLCs and control systems. Its SPI interface simplifies integration with industrial microcontrollers, and the diagnostic features enable real-time fault detection. The device's robust protection (overcurrent, overtemperature) ensures reliable operation in harsh factory environments. For example, in a packaging machine, the L9954-TR can control multiple pneumatic valves, with each channel driving a solenoid. The SPI diagnostics allow the PLC to detect valve failures, reducing downtime. The wide operating temperature range (-40C to +150C) suits industrial environments, and the PowerSO-36 package with exposed pad aids thermal management. Compared to relay-based solutions, the L9954-TR offers faster switching and longer lifespan, while reducing power consumption.
Recommended
LED Lighting Control
The L9954-TR can be used to control LED lighting in automotive and industrial applications. Each channel can drive an LED string or a single high-power LED, with current limited by external resistors. The SPI interface allows dimming and on/off control, while diagnostics detect open or shorted LEDs. In automotive lighting, the L9954-TR can control daytime running lights, turn signals, and interior lighting. The device's low-side configuration is suitable for common-anode LED configurations. The 1.5A per channel capability supports multiple LEDs in series, and the protection features prevent damage from LED failures. Compared to dedicated LED drivers, the L9954-TR offers flexibility and diagnostics, though it may require external current limiting.
Recommended
Relay and Solenoid Driver
The L9954-TR is specifically designed for driving relays and solenoids, which are common in automotive and industrial systems. Its internal clamping handles inductive loads, and the SPI diagnostics provide feedback on relay health. In a typical relay driver application, the L9954-TR replaces discrete transistor circuits, reducing component count and improving reliability. The device can drive relays with coil currents up to 1.5A, and the open-load detection can identify a faulty relay coil. The SPI interface allows the MCU to monitor each channel's status, enabling predictive maintenance. Compared to smart high-side switches, the L9954-TR offers lower cost per channel and simpler thermal management, as heat is dissipated in the low-side switch.
Recommended
Test and Measurement Equipment
In test and measurement equipment, the L9954-TR can be used for switching various loads in automated test setups. Its SPI interface allows precise control and diagnostics, making it suitable for ATE (Automated Test Equipment). For example, in a PCB tester, the L9954-TR can switch power to different test points, with each channel controlling a relay. The diagnostic features help identify faulty relays, improving test reliability. The device's wide supply voltage range and robust protection make it suitable for bench power supplies and load banks. Compared to using discrete MOSFETs, the L9954-TR simplifies design and reduces board space, while providing comprehensive fault reporting.
Recommended
General Purpose Switching
The L9954-TR can be used as a general-purpose 8-channel low-side switch in various applications, including consumer electronics, white goods, and smart home systems. Its SPI interface allows easy integration with microcontrollers, and the diagnostics provide valuable feedback. For example, in a smart home hub, the L9954-TR can control multiple loads such as lights, fans, and locks. The device's low standby current is beneficial for battery-powered devices. The protection features ensure safe operation, and the PowerSO-36 package is suitable for compact designs. Compared to using multiple discrete switches, the L9954-TR offers a cost-effective and space-saving solution.
Recommended
Recommended Products Summary
Engineering reference data for L9954-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9954 | TLE6228GP |
|---|---|---|---|
| Package | PowerSO-36 | PowerSO-36 | PowerSO-36 |
| Brand | STMicroelectronics | STMicroelectronics | Infineon |
| Number of Channels | 8 | 8 | 8 |
| SPI Interface | Yes, 16-bit, up to 5 MHz | Yes, 16-bit, up to 5 MHz | Yes, SPI |
Key Differentiators
- 8-channel integration with SPI diagnostics (vs Discrete transistor solutions)
- AEC-Q100 qualification (vs TLE6228GP (Infineon))
- Low standby current of 10 uA (vs TLE6228GP)
Design Notes
The L9954-TR in PowerSO-36 package has an exposed pad that must be soldered to a PCB copper area for heat dissipation. For continuous operation at 1.5A per channel, ensure the PCB copper area is at least 2 square inches to keep junction temperature below 150C. Use thermal vias to connect the pad to inner layers.
Place a 100 nF ceramic capacitor close to the VCC pin and a 10 uF electrolytic capacitor on the VS pin to handle inrush currents. Keep SPI lines short and route them away from high-current switching traces to minimize noise. Use a ground plane to reduce EMI.
Do not exceed the absolute maximum ratings, especially the load supply voltage of 40V. Ensure the SPI chip select (CSN) is pulled high during power-up to avoid unintended outputs. For inductive loads, verify that the internal clamping is sufficient; otherwise, add external flyback diodes.
Compliance Information
RoHS compliant and AEC-Q100 qualified per ST datasheet. REACH compliance is assumed based on ST's policy, but not explicitly stated in the provided data.