L9984 - Automotive Quad Low-Side Driver | STMicroelectronics
MPN: L9984 ✓ 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 | $2.15 | $2,150.00 |
L9984 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 through a simple logic interface. In automotive systems, low-side drivers are essential for controlling actuators, lights, and motors, where the load is connected between the battery positive terminal and the driver output. The L9984 belongs to the family of smart power switches, which integrate protection and diagnostic features to enhance system reliability and reduce external component count.
Key features of the L9984 include overcurrent protection, thermal shutdown, and undervoltage lockout, ensuring safe operation under fault conditions. Each channel has an open-load detection capability, which is critical for diagnosing wiring faults in automotive harnesses. The device also features a serial peripheral interface (SPI) for advanced diagnostics and control, allowing the microcontroller to read fault status and control each output independently. The outputs are protected against short-circuit and over-temperature, with a typical overcurrent threshold of 2.5A per channel.
The L9984 utilizes a robust BCD (Bipolar-CMOS-DMOS) technology, which combines the benefits of bipolar analog circuits, CMOS logic, and DMOS power transistors. This technology enables high current handling with low on-resistance, typically 0.5 ohm per channel, minimizing power dissipation and improving efficiency. The device is designed to operate over the automotive temperature range of -40°C to +150°C, making it suitable for under-hood applications. The PowerSO-20 package with exposed pad provides a low thermal resistance of 35°C/W, allowing efficient heat dissipation without external heatsinks in moderate power applications.
Typical applications include automotive body control modules, lighting control, relay drivers, and solenoid drivers in transmission control units. The L9984 is also used in industrial automation for driving valves and actuators, where its robust protection features ensure reliable operation in harsh environments. The SPI interface enables seamless integration with microcontrollers, providing real-time diagnostics and reducing wiring complexity.
When designing with the L9984, it is essential to ensure proper PCB layout with adequate copper area for heat dissipation, especially when driving multiple channels at high current. The exposed pad should be connected to the ground plane with multiple vias to enhance thermal performance. Additionally, the SPI lines should be kept short and shielded to minimize electromagnetic interference, and the supply voltage should be decoupled with a 100nF ceramic capacitor close to the VCC pin.
Drop-in alternatives for L9984 — 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 L9984 (same form factor and footprint) — differing in On-Resistance (per channel), Operating Temperature Range, Output Current per Channel, Protection Features, Supply Voltage Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
L9985
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.1 / Unit
View Datasheet →VNQ7004
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
BTS7008
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
L9984 Maximum Ratings & Electrical Characteristics
| Number of Channels | 4 |
| Supply Voltage Range | 4.5 V to 40 V |
| Output Current per Channel | 1.5 A (continuous) |
| On-Resistance (per channel) | 0.5 ohm (typical) |
| Overcurrent Threshold | 2.5 A (typical) |
| Operating Temperature Range | -40°C to +150°C |
| Package | PowerSO-20 |
| Mounting Type | Surface Mount |
| Thermal Resistance, Junction-to-Ambient | 35 °C/W |
| Interface | SPI |
| Protection Features | Overcurrent, thermal shutdown, undervoltage lockout, open-load detection |
| Output Type | Low-side |
| Logic Input Voltage | 3.3 V / 5 V compatible |
| RoHS Status | Compliant |
| AEC-Q100 Qualified | Yes |
L9984 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 | GND — Ground |
| Pin 6 | VCC — Supply voltage |
| Pin 7 | SCK — SPI clock |
| Pin 8 | SDI — SPI data input |
| Pin 9 | SDO — SPI data output |
| Pin 10 | CS — SPI chip select |
| Pin 11 | IN1 — Logic input for channel 1 |
| Pin 12 | IN2 — Logic input for channel 2 |
| Pin 13 | IN3 — Logic input for channel 3 |
| Pin 14 | IN4 — Logic input for channel 4 |
| Pin 15 | NC — Not connected |
| Pin 16 | NC — Not connected |
| Pin 17 | NC — Not connected |
| Pin 18 | NC — Not connected |
| Pin 19 | NC — Not connected |
| Pin 20 | NC — Not connected |
Typical Applications
L9984 is suitable for 6 applications: Automotive Body Control Module, Lighting Control, Relay Driver, Solenoid Driver in Transmission Control, Industrial Automation, LED Lighting Modules.
Automotive Body Control Module
The L9984 is used in body control modules to drive exterior and interior lighting, relays for power windows, and door locks. Its four channels allow independent control of multiple loads, while the SPI interface provides diagnostics for fault detection. The wide supply voltage range (4.5V to 40V) accommodates both 12V and 24V automotive systems, and the AEC-Q100 qualification ensures reliability in harsh environments. The overcurrent and thermal protection prevent damage to the module and wiring, making it ideal for centralized body electronics.
Recommended
Lighting Control
The L9984 can drive automotive lighting such as headlamps, tail lamps, and interior lights. Each channel can sink up to 1.5A, sufficient for incandescent bulbs and LED modules with current limiting. The open-load detection feature is particularly useful for detecting burnt-out bulbs, enabling the system to alert the driver. The device's thermal shutdown protects against over-temperature when driving high-power lamps, and the SPI interface allows dimming control via PWM signals from the microcontroller.
Recommended
Relay Driver
The L9984 is ideal for driving relays in automotive and industrial systems. Its low on-resistance (0.5 ohm) minimizes voltage drop across the switch, ensuring reliable relay operation. The built-in clamping diodes handle inductive kickback when the relay coil is de-energized, protecting the driver from voltage spikes. The overcurrent protection prevents damage if a relay coil shorts, and the SPI interface enables monitoring of each relay's status. This makes the L9984 a robust solution for controlling motors, heaters, and other high-current loads through relays.
Recommended
Solenoid Driver in Transmission Control
In automatic transmissions, the L9984 drives solenoids that control hydraulic pressure for gear shifting. The device's fast switching capability and low on-resistance ensure precise control of solenoid current, which is critical for smooth gear changes. The thermal shutdown protects the driver in high-temperature transmission environments, and the SPI interface provides real-time diagnostics for solenoid health. The AEC-Q100 qualification ensures long-term reliability in this demanding application.
Recommended
Industrial Automation
The L9984 is used in industrial automation to drive valves, actuators, and solenoids in process control systems. Its wide supply voltage range (4.5V to 40V) makes it compatible with 24V industrial power supplies. The robust protection features (overcurrent, thermal shutdown) ensure reliable operation in harsh factory environments. The SPI interface allows seamless integration with PLCs and industrial microcontrollers, enabling centralized control and diagnostics. The PowerSO-20 package with exposed pad provides efficient heat dissipation for continuous operation.
Recommended
LED Lighting Modules
The L9984 can drive LED lighting modules in automotive and industrial applications. Each channel can sink up to 1.5A, which is sufficient for high-power LEDs when used with appropriate current-limiting resistors or LED drivers. The open-load detection feature helps identify faulty LED strings, simplifying maintenance. The device's thermal shutdown protects against over-temperature when driving multiple LEDs, and the SPI interface allows individual channel control for dynamic lighting effects. This makes the L9984 a versatile solution for LED lighting systems.
Recommended
Recommended Products Summary
Engineering reference data for L9984 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9985 | VNQ7004 | BTS7008 |
|---|---|---|---|---|
| Package | PowerSO-20 | PowerSO-20 | PowerSO-20 | PowerSO-20 |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | Infineon |
| Number of Channels | 4 | 4 | 4 | 4 |
| Output Current per Channel | 1.5 A | 2 A | 1.5 A | 1.5 A |
| On-Resistance | 0.5 ohm | 0.3 ohm | 0.5 ohm | 0.4 ohm |
| Supply Voltage Range | 4.5V to 40V | 4.5V to 40V | 4.5V to 40V | 4.5V to 40V |
| Interface | SPI | SPI | SPI | SPI |
| Protection Features | Overcurrent, thermal shutdown, UVLO, open-load | Overcurrent, thermal shutdown, UVLO, open-load | Overcurrent, thermal shutdown, UVLO, open-load | Overcurrent, thermal shutdown, UVLO, open-load |
Key Differentiators
- Higher output current capability (vs L9985)
- Lower on-resistance (vs BTS7008)
- Same-brand compatibility (vs BTS7008)
Design Notes
The L9984 in PowerSO-20 package has a junction-to-ambient thermal resistance of 35°C/W. When driving all four channels at 1.5A each with a supply voltage of 13.5V and load resistance of 9 ohm, the power dissipation per channel is approximately 1.125W (I^2 * R_on = 1.5^2 * 0.5). Total dissipation is 4.5W, resulting in a junction temperature rise of 157.5°C above ambient. For reliable operation, ensure adequate PCB copper area and consider using the exposed pad with thermal vias to reduce thermal resistance.
Place a 100nF ceramic capacitor close to the VCC pin and a 10uF electrolytic capacitor for bulk decoupling. The exposed pad should be soldered to a large ground plane with multiple vias to enhance heat dissipation. Keep SPI traces short and shielded to minimize EMI, and route them away from high-current output traces to avoid coupling.
Do not exceed the absolute maximum supply voltage of 40V. Ensure the logic inputs are not left floating; use pull-up or pull-down resistors as needed. When driving inductive loads, the internal clamping diodes handle kickback, but for high-energy loads, external TVS diodes may be required. Also, verify the SPI communication timing to avoid data corruption.
Compliance Information
AEC-Q100 qualified per STMicroelectronics product page. RoHS compliant.
