STMicroelectronics L9788TR

Overview

L9788TR from STMicroelectronics is a multifunction automotive IC for 4-cylinder engine management systems, integrating pre-boost/pre-buck regulators, five 5 V tracking regulators (150 mA each), four LS injector drivers, two O2 heater drivers with current sense, two cam/solenoid drivers, five relay drivers, two LED drivers, three LS/HS smart-start drivers, one main relay driver with reverse-battery protection, five pre-drivers for external FETs, six ignition pre-drivers, K-Line/LIN 2.1, CAN-FD with wake-up, VRS interface, watchdog, and temperature monitoring.

For engineers reviewing the L9788TR datasheet, L9788TR pinout, L9788TR application, or L9788TR equivalent, key selection criteria include coordinated soft-start sequencing, ISO 26262 system compliance support, dual-bandgap reference stability, microsecond-channel MSC for differential single-ended sensing, and integrated charge-pump for high-side gate drive in harsh automotive environments.

Technical Context

The L9788TR implements a BCD-based mixed-signal architecture combining power regulation (1x pre-boost, 1x pre-buck, 1x 5 V linear @ 1 A, 3x 5 V tracking @ 150 mA), precision analog sensing (VRS input, O2H current sense, temperature sensor), and configurable low-/high-side drivers across 24 output channels. Its CAN-FD interface supports wake-up via bus activity, while LIN 2.1 and K-Line ensure legacy diagnostics compatibility.

Regulator coordination includes synchronized soft-start, external voltage monitoring (VSENSE4_MON), and internal diode-protected MRD. The MSC block provides microsecond-resolution timing for crank/cam signal decoding, and SEO function enables engine synchronization without external hardware.

Key Specifications

Pinout & Package

L9788TR is housed in an LQFP100 package (14 mm × 14 mm × 1.4 mm) with exposed thermal pad (7.6 mm × 7.6 mm) for enhanced heat dissipation in under-hood automotive applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multifunction engine management IC applications.

Compared with MC33816 and RH850/P1M, L9788TR delivers higher integration density with embedded CAN-FD, MSC timing, and coordinated regulator sequencing-reducing BOM count by ≥12 components and eliminating external VRS signal conditioning in compact ECU layouts.

Availability

L9788TR is available at Aetrix Electronics and suitable for automotive engine control units, start-stop systems, and emissions-compliant powertrain modules requiring stable component supply, AEC-Q100 qualification, and ISO 26262 functional safety support.

Supply support for L9788TR 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 silicon solutions for automotive, industrial, and consumer markets with emphasis on reliability, safety, and energy efficiency.

The L9788TR belongs to ST's Automotive Powertrain IC portfolio, engineered specifically to consolidate power regulation, signal conditioning, and actuator driving functions into a single AEC-Q100 qualified device for 4-cylinder ICE ECUs.

FAQ

What is the maximum junction temperature rating for L9788TR?

L9788TR is AEC-Q100 Grade 0 qualified with a maximum junction temperature of +150 °C. Thermal performance is enabled by its LQFP100 package with 7.6 mm × 7.6 mm exposed pad, which must be soldered to a thermally optimized PCB copper plane per ST's AN4640 layout guidelines to maintain safe operation under full load at ambient up to +105 °C.

Does L9788TR support both single-ended and differential VRS signal acquisition?

Yes - the VRS interface supports both single-ended and differential modes via configurable internal termination and gain settings. Differential mode uses pins FLW_IN_P and FLW_IN_N with programmable hysteresis and adaptive thresholding, enabling robust crank/cam signal capture even with high common-mode noise in 12 V vehicle architectures.

How does the SEO (Synchronization Output) function operate without MCU involvement?

The SEO function generates a deterministic, jitter-free synchronization pulse aligned to crankshaft position events using internal MSC timing logic. It operates autonomously from the host MCU, driven directly by decoded VRS edges and MSC counter states, and can be configured for rising/falling edge output with programmable pulse width - eliminating MCU interrupt latency in time-critical ignition timing loops.

Can the O2 heater drivers be used for other resistive loads beyond oxygen sensors?

Yes - the O2H1/O2H2 drivers support generic resistive loads up to 2.5 Ω at 12 V (delivering ~4.8 A per channel). Their current-sense outputs (CURR_Sense_O2H1/2) provide ratiometric analog voltage proportional to load current, enabling closed-loop thermal control of fuel vaporizers, EGR coolers, or cabin air heaters when paired with external ADC and PWM control logic.