L9978-TR - Automotive Quad Low-Side Driver | STMicroelectronics
料号： L9978-TR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.56 | $25.60 |
| 100 | $2.28 | $228.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.85 | $1,850.00 |
L9978-TR 概述
A low-side driver is a type of power switch that connects the load to ground when activated, commonly used to control relays, solenoids, LEDs, and other actuators in automotive body control modules and industrial control systems. It sits within the power management hierarchy as a discrete power switch, often integrated with protection features such as overcurrent, overtemperature, and short-circuit protection, making it a robust choice for harsh environments.
Key features of the L9978-TR include a low quiescent current of 50 µA in standby mode, making it suitable for battery-powered automotive systems, and a fast switching speed with rise/fall times of 5 µs. Each output is protected against overcurrent and overtemperature, and the device includes a common fault flag output for diagnostics. The PowerSO-20 package provides a thermal resistance of 35 °C/W, enabling reliable operation at high ambient temperatures up to 150 °C.
The L9978-TR utilizes a robust bipolar-CMOS-DMOS (BCD) process technology, integrating logic-level input control with high-current output stages. The device features an SPI interface for advanced diagnostics and control, allowing individual channel enable/disable and fault readback. This architecture ensures precise control and monitoring, reducing external component count and improving system reliability.
Typical applications include automotive body control modules for driving exterior and interior lighting, relay and solenoid drivers for engine management, and industrial PLC output stages. The wide supply range and automotive-grade qualification (AEC-Q100) make it ideal for 12V and 24V systems. In automotive lighting, the L9978-TR can directly drive LED modules with PWM dimming, while its fault diagnostics enable early detection of open or shorted loads.
When designing with the L9978-TR, ensure adequate PCB copper area for thermal dissipation, especially when driving multiple channels at high current. The exposed pad must be soldered to a thermal via array connected to the ground plane. Additionally, place a 100 nF decoupling capacitor close to the VCC pin and a 10 µF bulk capacitor at the supply input to handle inductive load switching transients.
直接替换替代料： L9978-TR ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： L9978-TR （相同外形与封装尺寸） ——差异在于 Package.
快速对比工具——选择替代料号进行并排对比：
L9978
✅ 直接替换✓ 有现货
$8.1 / 个
查看数据手册 →TLE6228GP
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
MC33289
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
L9978-TR 最大额定值与电气特性
| Number of Channels | 4 |
| 输出类型 | Low-Side Open-Drain |
| Supply Voltage Range | 4.5 V to 36 V |
| Maximum Output Current per Channel | 1.2 A |
| Quiescent Current (Standby) | 50 µA |
| 上升时间 | 5 µs |
| 下降时间 | 5 µs |
| 开关频率 | 0 Hz to 100 kHz |
| Thermal Resistance (θJA) | 35 °C/W |
| 工作温度范围 | -40 °C to +150 °C |
| 封装 | PowerSO-20 |
| 安装类型 | Surface Mount |
| MSL 等级 | 3 (168 hours) |
| RoHS 状态 | Compliant |
| AEC-Q100 Qualification | Qualified |
| 接口 | SPI |
| Protection Features | Overcurrent, Overtemperature, Short-Circuit |
L9978-TR 引脚配置
| 引脚 1 | OUT1 — Low-side output channel 1 |
| 引脚 2 | OUT2 — Low-side output channel 2 |
| 引脚 3 | OUT3 — Low-side output channel 3 |
| 引脚 4 | OUT4 — Low-side output channel 4 |
| 引脚 5 | GND — Ground |
| 引脚 6 | VCC — Supply voltage |
| 引脚 7 | SCK — SPI clock input |
| 引脚 8 | SDI — SPI data input |
| 引脚 9 | SDO — SPI data output |
| 引脚 10 | CS — SPI chip select |
| 引脚 11 | IN1 — Input control for channel 1 |
| 引脚 12 | IN2 — Input control for channel 2 |
| 引脚 13 | IN3 — Input control for channel 3 |
| 引脚 14 | IN4 — Input control for channel 4 |
| 引脚 15 | FAULT — Fault flag output (active low) |
| 引脚 16 | NC — No connect |
| 引脚 17 | NC — No connect |
| 引脚 18 | NC — No connect |
| 引脚 19 | NC — No connect |
| 引脚 20 | NC — No connect |
| 引脚 PAD | Exposed Pad — Thermal pad, connect to ground |
典型应用
L9978-TR 适用于 6 应用s: Automotive Body Control Module, Industrial PLC Output Stage, Automotive Lighting Control, Relay and Solenoid Driver, LED Matrix Display Driver, Power Distribution Switch.
Automotive Body Control Module
The L9978-TR is ideal for automotive body control modules (BCMs) where it drives exterior and interior lighting, relays, and solenoids. Its AEC-Q100 qualification and wide supply range (4.5V to 36V) ensure reliable operation in 12V and 24V vehicle systems. The SPI interface enables centralized diagnostics, allowing the BCM to monitor each channel for open or shorted loads. With a 1.2A per channel output, it can directly drive LED modules with PWM dimming, while the low 50 µA standby current minimizes battery drain when the vehicle is off. The PowerSO-20 package with exposed pad facilitates thermal management in the confined space of a BCM enclosure.
推荐
Industrial PLC Output Stage
In industrial programmable logic controllers (PLCs), the L9978-TR serves as a robust output stage for driving actuators, valves, and indicator lamps. Its 4.5V to 36V supply range accommodates various industrial power rails, and the overcurrent and overtemperature protection ensure safe operation in harsh factory environments. The SPI interface allows the PLC to read fault status and reconfigure outputs without additional wiring. The fast 5 µs rise/fall times enable precise timing for high-speed switching applications. The device's wide operating temperature range (-40°C to +150°C) makes it suitable for unheated factory floors and outdoor installations.
推荐
Automotive Lighting Control
The L9978-TR is well-suited for automotive lighting control, including headlamps, tail lamps, and interior lighting. Each channel can drive up to 1.2A, sufficient for LED modules or incandescent bulbs. The PWM capability up to 100 kHz allows for smooth dimming without visible flicker. The device's fault diagnostics can detect open or shorted bulbs, enabling the vehicle to alert the driver to failed lights. The AEC-Q100 qualification ensures reliability under extreme temperature and vibration conditions. The low standby current is critical for maintaining battery charge when the vehicle is parked.
推荐
Relay and Solenoid Driver
The L9978-TR can directly drive relays and solenoids in automotive and industrial systems. Its open-drain outputs can sink the coil current (up to 1.2A) and include freewheeling protection to handle inductive kickback. The SPI interface allows individual channel control and fault monitoring, simplifying the design of multi-relay control boards. The device's thermal protection prevents damage during prolonged activation of multiple relays. The wide supply range supports both 12V and 24V relay coils, making it a versatile choice for various applications.
推荐
LED Matrix Display Driver
The L9978-TR can be used to drive LED matrix displays in automotive dashboards or industrial signage. Each channel can drive a column or row of LEDs, and the SPI interface allows efficient multiplexing and brightness control. The fast switching speed enables high refresh rates without ghosting. The device's current sinking capability (1.2A per channel) is sufficient for driving multiple LEDs in parallel. The fault diagnostics can detect open or shorted LED strings, simplifying maintenance. The wide temperature range ensures reliable operation in outdoor displays.
推荐
Power Distribution Switch
The L9978-TR can function as a power distribution switch in automotive or industrial systems, enabling or disabling power to various subsystems. Its four channels can independently control power to sensors, actuators, or communication modules. The SPI interface allows the system controller to manage power sequencing and monitor current draw. The device's protection features prevent damage from short circuits or overcurrent conditions. The low standby current is beneficial for systems that require minimal power consumption in sleep mode.
推荐
推荐产品汇总
工程参考数据： L9978-TR ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | L9978 | TLE6228GP | MC33289 |
|---|---|---|---|---|
| Package | PowerSO-20 | PowerSO-20 | PowerSO-20 | PowerSO-20 |
| Brand | STMicroelectronics | STMicroelectronics | Infineon | NXP Semiconductors |
| Number of Channels | 4 | 4 | 4 | 4 |
| Supply Voltage Range | 4.5V to 36V | 4.5V to 36V | 4.5V to 36V | 4.5V to 36V |
| Output Current per Channel | 1.2A | 1.2A | 1.2A | 1.2A |
| Interface | SPI | SPI | SPI | SPI |
| AEC-Q100 | Qualified | Qualified | Qualified | Qualified |
关键差异点
- Low standby current of 50 µA （对比 TLE6228GP)
- AEC-Q100 qualified （对比 MC33289)
- SPI interface with advanced diagnostics （对比 TLE6228GP)
设计说明
The L9978-TR has a thermal resistance (θJA) of 35 °C/W. When driving all four channels at 1.2A each with a supply voltage of 36V and load voltage drop of 1V, the total power dissipation is approximately 4.8W, resulting in a junction temperature rise of 168°C above ambient. To maintain junction temperature below 150°C, ensure adequate PCB copper area and thermal vias connected to the exposed pad. For high-power applications, consider using a heatsink or forced air cooling.
Place a 100 nF ceramic decoupling capacitor as close as possible to the VCC pin (pin 6) and a 10 µF bulk capacitor at the supply input to handle inductive load switching transients. The exposed pad must be soldered to a thermal via array connected to the ground plane to improve heat dissipation. Keep SPI signal traces short and shielded to minimize noise coupling.
When driving inductive loads such as relays or solenoids, ensure proper freewheeling protection (e.g., external flyback diodes) to prevent voltage spikes from damaging the output transistors. The L9978-TR includes internal protection, but external diodes are recommended for high-energy loads. Also, avoid exceeding the absolute maximum supply voltage of 36V, as this can cause permanent damage. Verify SPI communication timing and register configuration to prevent unintended output states.
合规信息
RoHS compliant per STMicroelectronics product page. AEC-Q100 qualified for automotive applications. Halogen-free status not specified in provided data.
