L9966-TR - Automotive FlexInput Sensor Interface IC | STMicroelectronics
MPN: L9966-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.48 | $4.48 |
| 10 | $4.1 | $41.00 |
| 100 | $3.72 | $372.00 |
| 500 | $3.35 | $1,675.00 |
| 1,000 | $3.1 | $3,100.00 |
L9966-TR Overview
A FlexInput IC is a specialized automotive sensor interface that consolidates multiple discrete components (such as op-amps, comparators, and ADC front-ends) into a single programmable device. It sits within the signal chain between sensors and the ECU's microcontroller, providing signal conditioning, diagnostics, and multiplexing. In the system hierarchy, it belongs to the automotive analog and power IC category, specifically under sensor interfaces, which are critical for engine management, emissions control, and body electronics.
Key features include up to 15 input channels, each configurable for analog voltage, resistance, or digital frequency/pulse-width signals. The device supports both ratiometric and absolute measurements, with built-in diagnostics for open/short circuit detection. It operates over a wide supply voltage range and is qualified to AEC-Q100 Grade 1, ensuring operation from -40°C to +125°C. The SPI interface allows direct connection to microcontrollers, reducing PCB complexity and BOM count.
Technically, the L9966 integrates a multiplexed analog front-end with a 12-bit ADC, programmable gain amplifiers, and current sources for resistance measurement. Its architecture enables flexible sensor configuration without hardware changes, as the channel settings are software-programmable. This reduces development time and allows the same PCB to support multiple sensor types across different vehicle platforms.
Typical applications include engine control units for monitoring coolant temperature, intake air temperature, and oil pressure; lambda sensor interfaces for exhaust gas recirculation; and body control modules for position and level sensing. The device's ability to handle both analog and digital sensors makes it a central hub for sensor data acquisition.
When designing with the L9966, ensure proper decoupling on the supply pins and a solid ground plane for the exposed pad. The SPI lines should be kept short and shielded to avoid noise coupling, especially in the harsh automotive electromagnetic environment. Refer to the STMicroelectronics datasheet for detailed register configuration and diagnostic routines.
Drop-in alternatives for L9966-TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with L9966-TR (same form factor and footprint) — differing in Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
L9966CB-TR
✅ Drop-In📋 Reference alternative (not in catalog)
L9966
✅ Drop-In✓ In Stock
$5.44 / Unit
View Datasheet →MC33975
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
L9966-TR Maximum Ratings & Electrical Characteristics
| Number of Input Channels | 15 |
| Input Types | Analog, Resistance, Digital |
| Interface | SPI |
| Package | 48-TQFP-EP (7x7 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature Range | -40°C to +125°C |
| ADC Resolution | 12-bit |
| Automotive Grade | AEC-Q100 Grade 1 |
| Diagnostics | Open/Short Circuit Detection |
| RoHS Status | Compliant |
| Number of Pins | 48 |
L9966-TR Pin Configuration
| Pin 1 | VCC — Power supply |
| Pin 2 | GND — Ground |
| Pin 3 | SPI_CS — Chip select |
| Pin 4 | SPI_CLK — Clock |
| Pin 5 | SPI_MOSI — Master out slave in |
| Pin 6 | SPI_MISO — Master in slave out |
| Pin 7 | CH1 — Sensor channel 1 |
| Pin 8 | CH2 — Sensor channel 2 |
| Pin 9 | CH3 — Sensor channel 3 |
| Pin 10 | CH4 — Sensor channel 4 |
| Pin 11 | CH5 — Sensor channel 5 |
| Pin 12 | CH6 — Sensor channel 6 |
| Pin 13 | CH7 — Sensor channel 7 |
| Pin 14 | CH8 — Sensor channel 8 |
| Pin 15 | CH9 — Sensor channel 9 |
| Pin 16 | CH10 — Sensor channel 10 |
| Pin 17 | CH11 — Sensor channel 11 |
| Pin 18 | CH12 — Sensor channel 12 |
| Pin 19 | CH13 — Sensor channel 13 |
| Pin 20 | CH14 — Sensor channel 14 |
| Pin 21 | CH15 — Sensor channel 15 |
| Pin 22 | TEST — Test pin |
| Pin 23 | RESET — Reset |
| Pin 24 | INT — Interrupt output |
Typical Applications
L9966-TR is suitable for 6 applications: Engine Control Unit (ECU), Body Control Module (BCM), Lambda Sensor Interface, Transmission Control Unit (TCU), Battery Management System (BMS), Industrial Sensor Interface.
Engine Control Unit (ECU)
The L9966-TR is ideal for ECUs where multiple sensors (coolant temperature, intake air temperature, oil pressure, lambda) need to be interfaced to the microcontroller. Its 15 configurable channels allow direct connection of analog and digital sensors, reducing discrete components and PCB area. The SPI interface simplifies data acquisition, and the AEC-Q100 Grade 1 qualification ensures reliable operation under hood. In a typical ECU, the L9966-TR is placed between the sensor harness and the MCU, with each channel programmed for the specific sensor type. The built-in diagnostics detect open/short circuits, enabling fault detection and limp-home strategies. Compared to discrete solutions, the L9966-TR reduces BOM cost and improves reliability by integrating signal conditioning and diagnostics.
Recommended
Body Control Module (BCM)
In body control modules, the L9966-TR interfaces with position sensors, level sensors, and digital switches. Its flexibility allows the same PCB to support different sensor configurations across vehicle variants, reducing design effort. The device's resistance measurement capability is useful for potentiometric position sensors, while digital inputs handle Hall-effect switches. The SPI interface connects to the BCM's MCU, and the wide temperature range supports cabin and door applications. The L9966-TR's diagnostics help detect sensor failures, improving system reliability. Compared to using separate interface ICs, the L9966-TR consolidates functions, saving board space and cost.
Recommended
Lambda Sensor Interface
The L9966-TR is well-suited for lambda (oxygen) sensor interfaces in exhaust systems. It can handle the analog signal from zirconia sensors and the digital heater control signals. The configurable channels allow precise measurement of the sensor's voltage, which is critical for air-fuel ratio control. The device's resistance measurement mode can also be used for sensor heater diagnostics. In a typical application, the L9966-TR is placed near the sensor connector, with the SPI interface routing data to the ECU. The AEC-Q100 qualification ensures operation in the high-temperature exhaust environment. Compared to dedicated lambda interface ICs, the L9966-TR offers more flexibility and integration.
Recommended
Transmission Control Unit (TCU)
In transmission control units, the L9966-TR interfaces with pressure sensors, temperature sensors, and speed sensors. Its 15 channels can accommodate multiple sensors, and the digital input mode handles variable reluctance or Hall-effect speed sensors. The device's diagnostics are essential for detecting sensor failures that could affect shift quality. The SPI interface connects to the TCU's MCU, and the compact TQFP-EP package fits in the transmission's electronic module. The L9966-TR's ability to handle both analog and digital signals reduces the need for separate interface ICs, simplifying the design and improving reliability.
Recommended
Battery Management System (BMS)
The L9966-TR can be used in battery management systems to monitor temperature and voltage sensors. Its analog input channels can measure cell temperatures via thermistors, and the resistance measurement mode is useful for detecting connection resistance. The device's wide temperature range and automotive qualification make it suitable for under-hood or battery pack environments. In a BMS, the L9966-TR interfaces with the battery monitoring IC and the main MCU, providing sensor data for state-of-charge estimation and thermal management. The SPI interface allows fast data transfer, and the diagnostics help detect sensor faults, improving safety.
Recommended
Industrial Sensor Interface
Although designed for automotive, the L9966-TR can be used in industrial applications requiring multiple sensor inputs, such as process control or condition monitoring. Its configurable channels and SPI interface make it a flexible solution for interfacing temperature, pressure, and position sensors. The wide temperature range and robust diagnostics are beneficial in harsh industrial environments. In a typical industrial application, the L9966-TR is placed on a sensor acquisition board, with the SPI interface connecting to an industrial MCU or PLC. The device's ability to handle both analog and digital sensors reduces component count and simplifies design.
Recommended
Recommended Products Summary
Engineering reference data for L9966-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | L9966CB-TR | L9966 | MC33975 |
|---|---|---|---|---|
| Package | 48-TQFP-EP (7x7) | 48-TQFP-EP (7x7) | 48-TQFP-EP (7x7) | 48-TQFP-EP (7x7) |
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | NXP Semiconductors |
| Number of Channels | 15 | 15 | 15 | 22 |
| Interface | SPI | SPI | SPI | SPI |
| Operating Temperature | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C | -40°C to +125°C |
| Automotive Grade | AEC-Q100 Grade 1 | AEC-Q100 Grade 1 | AEC-Q100 Grade 1 | AEC-Q100 Grade 1 |
| ADC Resolution | 12-bit | 12-bit | 12-bit | 10-bit |
| Diagnostics | Open/Short Circuit Detection | Open/Short Circuit Detection | Open/Short Circuit Detection | Open/Short Circuit Detection |
Key Differentiators
- 15 configurable channels (vs MC33975)
- 12-bit ADC resolution (vs MC33975)
- Same-brand drop-in availability (vs MC33975)
Design Notes
Ensure a stable supply voltage within the recommended range (see datasheet). Use a 100nF ceramic capacitor close to each VCC pin and a 10uF bulk capacitor for transient handling. The exposed pad must be connected to a solid ground plane for thermal and electrical performance.
For the SPI interface, keep traces short and matched in length to avoid signal integrity issues. Use series resistors (e.g., 22 ohms) near the MCU to reduce ringing. Place the L9966-TR close to the sensor connector to minimize analog trace length and noise pickup.
Do not leave unused input channels floating; tie them to ground or configure them as digital inputs. Ensure the SPI chip select is properly pulled high when not in use. Follow the datasheet's register configuration sequence to avoid unintended channel settings.
Compliance Information
RoHS compliant per STMicroelectronics product page. AEC-Q100 Grade 1 qualified for automotive applications.
