STMicroelectronics L9945TR

Overview

L9945TR 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), dual H-bridge (up to 2), and peak-and-hold (2 loads) configurations with 3.3 V/5 V logic-compatible I/O, 3.8–36 V battery input, and SPI-based diagnostics.

For engineers reviewing the L9945TR datasheet, L9945TR pinout, L9945TR application, or L9945TR equivalent, this device serves as a safety-critical load controller in engine management, chassis control, and body electronics where channel-level diagnosis, redundant disable, and EMI-optimized gate drive are required.

Technical Context

The L9945TR implements a fully programmable 8-channel output architecture with per-channel configuration via 32-bit SPI - enabling dynamic reassignment of channels between high-side (NMOS/PMOS), low-side (NMOS), H-bridge (4- or 8-channel), and peak-and-hold (2-load) modes. Each channel supports independent overcurrent threshold programming (64 levels) and ultra-fast shutdown (< 1 µs).

Its safety architecture includes dual external disable inputs (DIS/NDIS), built-in self-test (BIST), hardware self-check (HWSC) for VDD5, configurable communication watchdog, and redundant output monitoring via dedicated SPI registers - all compliant with ISO 26262 ASIL-B requirements for functional safety.

Key Specifications

Pinout & Package

TQFP64 exposed pad package (10 mm × 10 mm, 0.5 mm pitch); thermal pad must be soldered and connected to GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar MOSFET pre-driver applications.

Compared with TPIC2603DQPWRQ1 and BD3901FV-M, the L9945TR provides unmatched topology flexibility (HS/LS/H-bridge/P&H), full SPI diagnostics, and ASIL-B safety features - making it the only choice for modern automotive power distribution units requiring functional safety and multi-load adaptability.

Availability

L9945TR is available at Aetrix Electronics and suitable for engine control, transmission actuation, body electronics, and chassis systems requiring stable component supply, long-term automotive lifecycle support, and AEC-Q100 reliability validation.

Supply support for L9945TR 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, specializing in automotive, industrial, and power management ICs with broad manufacturing scale and automotive qualification expertise.

The L9945TR belongs to ST's automotive smart-power pre-driver product line, designed specifically for functional-safety-critical load control in 12 V/24 V vehicle architectures - emphasizing configurability, diagnosis depth, and ISO 26262 compliance.

FAQ

What is the purpose of the EN6 pin on the L9945TR?

The EN6 pin is a dedicated enable input for output channel 6, required to activate its driver when configured for safety-critical loads such as brake lights or airbag deployment circuits. It operates as an active-high signal and must be asserted before channel 6 can drive external MOSFETs - providing hardware-level isolation for ASIL-B functions.

How does the L9945TR implement overcurrent protection without external components?

The L9945TR supports two internal overcurrent detection methods: monitoring voltage across an external shunt resistor (via SNGP/GNSP pins) or measuring drain-to-source voltage of the external MOSFET (via DRN/GNSP pins). All 64 programmable thresholds and ultra-fast shutdown logic are implemented in hardware, eliminating need for external comparators or microcontroller polling.

Can the L9945TR drive both NMOS and PMOS high-side switches?

Yes - the L9945TR supports NMOS high-side drive using its VGBHI boosted supply (VPS + 12 V), and PMOS high-side drive using standard VPS as gate reference. The LS_HS_config_xx and N_P_config_xx bits in SPI registers select side and FET type per channel, with PMOS restricted to high-side configuration only.

What is the role of the CH1–CH4 pins in the L9945TR charge pump system?

CH1–CH4 are flying capacitor nodes for the dual charge pump circuit: CH1/CH2 form one pump stage generating VGBHI for channels 1–4, while CH3/CH4 form a second stage for channels 5–8. These pins require external ceramic capacitors (typically 100 nF) connected in flying-capacitor topology to enable independent high-side gate drive across both H-bridge groups.