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Automotive engine management control IC for small engines

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Product overview


L9177A is a device realized in ST BCD proprietary technology, able to provide the full set of power supplies and signal preprocessing peripherals needed to control a 2 Cylinder internal combustion Engine for Low End Application (e.g. small motorcycle, K-car, nautical engines, etc.).

L9177A integrates a 5 V 300 mA main voltage regulator, a 5 V 40 mA tracking regulator for sensor supply and a 2.5 mA 5 V standby regulator.

The two channels injector drivers, the O2 sensor heater and two relay drivers can be controlled both with parallel input and with SPI interface. One additional relay driver and the current limited low side driver are controlled by SPI. The stepper motor driver is designed for a double winding coil motor, used for engine idle speed control.

Low side drivers implement SR control to minimize emission.

A protected 50 mA high side driver is provided.

A Variable Reluctance Sensor interface allows the connection to a commercial magnetic pick-up, allowing the indirect measurement of internal combustion engine crank angle. A K-line (standard ISO-9141 compatible) is provided as data communication interface.

All functionalities are fully protected and provide complete diagnostics via a 24-bit SPI interface. An overall protection against over temperature is provided as well.

The device is available in TQFP64 10x10 mm package with exposed pad for power dissipation optimization.

  • All features

    • AEC-Q100 qualified
    • Supply voltage from 6 V to 18 V
      • Basic functionality guaranteed down to 3.9 V
    • 5 V regulator up to 300 mA with thermal shutdown protection in current limitation condition
    • 5 V tracking regulator up to 40 mA and short to battery protection
    • 5 V standby regulator up to 2.5 mA
    • 2 channels injectors drivers
      • Parallel and serial driving
      • Output internally clamped to 60 V
      • Minimum overcurrent at 2.8 A
      • Ron 0.6 Ω worst case (at Tj = 150 °C)
    • 3 relay drivers
      • 2 with parallel and serial driving, 1 with serial driving
      • Output internally clamped to 45 V
      • Minimum guaranteed output current 1 A
      • Ron 1.5 Ω worst case (at Tj = 150 °C)
    • Tachometer driver
      • Parallel and serial driving
      • Minimum guaranteed output current 25 mA
      • Ron 5 Ω worst case (at Tj = 150 °C)
    • Current limited low side driver (LSD)
      • Serial driving
      • Output internally clamped to 45 V
      • Minimum guaranteed output current 1 A (2 A during in-rush)
      • Ron 1.5 Ω worst case (at Tj = 150 °C)
    • Stepper motor driver
      • Parallel driving
      • Minimum guaranteed output current 500 mA - full step
      • Ron 2.6 Ω worst case on the diagonal (at Tj = 150 °C)
    • O2 sensor heater
      • Parallel and serial driving
      • Output internally clamped to 45 V
      • Minimum guaranteed output current 3 A
      • Ron 0.5 Ω worst case (at Tj = 150 °C)
    • Protected high side driver
      • 100 mA min. current limitation threshold
    • Full diagnosis by SPI
      • Injector driver: OL, STG, OC
      • Relay and current limited LSD drivers: OL, STG, OC
      • O2 sensor heater: OL, STG, OC
      • Tachometer: OL, STG, OC
      • Stepper motor driver: OL, STG, STB, OC
      • general diagnostic: over-temperature
    • Protection for STB, STG (for stepper motor drivers and tracking regulator)
    • Self configuring variable reluctance sensor interface
    • K-line transceiver
    • Microcontroller reset logic
    • Small Factor form package TQFP64 10 x 10 mm exposed pad down

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STMicroelectronics - L9177A

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Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
TQFP 64 10x10x1.0 Automotive Ecopack2



TQFP 64 10x10x1.0

Material Declaration**:


Marketing Status



TQFP 64 10x10x1.0



RoHS Compliance Grade


(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

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