STMicroelectronics L9945

Overview

L9945 from STMicroelectronics is an AEC-Q100 qualified 8-channel configurable MOSFET pre-driver for automotive 12 V and 24 V battery systems, supporting high-side (N/P-channel), low-side (N-channel), H-bridge (up to two), and peak-and-hold (two loads) configurations with 3.3 V/5 V logic compatibility, 3.8–36 V battery input range, and SPI-based diagnostics.

For engineers reviewing the L9945 datasheet, L9945 pinout, L9945 application, or L9945 equivalent, this device serves as a safety-critical load controller in engine management, body control modules, and chassis systems-requiring precise overcurrent threshold programming, dual external disable inputs (DIS/NDIS), EN6-enabled safety outputs, and 10-bit battery/die temperature monitoring via SPI.

Technical Context

The L9945 implements a fully programmable channel architecture where each of eight outputs can be independently assigned as high-side (NMOS/PMOS), low-side (NMOS), H-bridge leg (four or eight channels), or peak-and-hold pair (CH1+CH4 or CH2+CH3), with dedicated EN6 enable for safety-critical channel 6 activation.

Its diagnostic subsystem delivers per-channel short-to-battery, short-to-ground, and open-load detection using configurable voltage-sensing methods-including external shunt resistor or MOSFET drain-source voltage-and latches faults even during active SPI read cycles, while hardware self-checks (HWSC, BIST) and configurable communication watchdog (CC) enforce ASIL-B compliance.

Key Specifications

Pinout & Package

TQFP64 exposed pad (10 mm × 10 mm, 0.5 mm pitch); thermal pad must be soldered and connected to GND. GNDIO and GNDCP pins require shorting and grounding.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-channel automotive pre-driver applications.

Compared with TPIC2603D and MC33883, the L9945 uniquely combines AEC-Q100 qualification, EN6-enabled safety channel, dual H-bridge/peak-and-hold capability, and 64-step programmable overcurrent thresholds - making it the only option for ASIL-B-compliant multi-configuration automotive load control.

Availability

L9945 is available at Aetrix Electronics and suitable for engine control units, body control modules, chassis control systems, and commercial vehicle power distribution requiring stable component supply across automotive production lifecycles.

Supply support for L9945 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, and automotive-grade analog devices for industrial and transportation markets.

The L9945 belongs to ST's Automotive Smart Power family, engineered specifically for functional-safety-critical load driving in 12 V/24 V vehicle electrical architectures - emphasizing diagnostic completeness, redundancy, and ASIL-B compliance.

FAQ

What is the purpose of the EN6 pin on the L9945?

The EN6 pin is a dedicated enable input for channel 6, required to activate its output driver when used in safety-critical applications such as cylinder-specific injector control or electronic parking brake actuation. It operates as an active-high signal with internal pull-down, ensuring default disable state during MCU initialization or fault conditions.

How does the L9945 implement overcurrent protection without external sense resistors?

The L9945 supports two overcurrent sensing methods: monitoring voltage across an external shunt resistor (via dedicated analog inputs) or measuring external MOSFET drain-to-source voltage (V_DS) through DRNx/SNGPx/GNSPx pins. Both methods feed into 64 programmable thresholds per channel, triggering ultra-fast output shutdown within 2 µs upon violation.

Can the L9945 drive both N-channel and P-channel MOSFETs on the same channel?

No - channel configuration is per-output and mutually exclusive: high-side mode supports either NMOS or PMOS (selected via N_P_config_xx bit), but low-side mode supports NMOS only. PMOS use is restricted to high-side configurations due to gate-drive voltage constraints and internal charge-pump architecture.

What is the function of the NDIS pin beyond being a disable input?

The NDIS pin operates bidirectionally: as an input, it provides a second redundant disable path (active-low); as an output, it pulls low internally during fault events (e.g., overtemperature, VDD undervoltage, or latchable diagnostics), generating an interrupt to the host MCU without requiring polling - enabling deterministic fault response in time-critical systems.