AC7840-SENSOR
High-precision multi-channel sensor interface with 24-bit ADC and ASIL-B support for safety-critical sensing
Product Overview
Description
The AC7840-SENSOR is a high-precision multi-channel sensor interface featuring 24-bit ADC and advanced signal processing capabilities.
With 8 input channels, programmable gain amplifiers, and ASIL-B safety features, it is ideal for safety-critical sensor acquisition systems.
The device supports various sensor types including resistive, capacitive, and voltage-output sensors with high accuracy.
Product Series
AC
Primary Application
Engine management sensors
Key Features
- 24-bit high-resolution ADC
- 8 multiplexed input channels
- Programmable gain amplifiers (1x to 128x)
- Multiple sensor type support
- ASIL-B functional safety features
- Integrated sensor excitation
- SPI and SENT interfaces
- AEC-Q100 Grade 1 qualified
Specifications
| Supply Voltage | 3.3V to 5V |
|---|---|
| ADC Resolution | 24-bit |
| Input Channels | 8 multiplexed |
| Accuracy | 0.1% over temperature |
| Temperature Range | -40°C to +125°C |
| Safety Level | ASIL-B support |
Applications
Engine management sensors
Sensor signal conditioning
Transmission sensors
Sensor signal conditioning
Chassis position sensors
Sensor signal conditioning
Battery monitoring systems
Battery and charging management
Safety-critical sensor systems
Sensor signal conditioning
FAE Expert Insights
"The AC7840-SENSOR is my recommended solution for safety-critical multi-sensor acquisition systems. The 24-bit ADC provides exceptional resolution for precise measurement, while the 8-channel multiplexer allows flexible sensor configuration. I have successfully used this interface in engine management and battery monitoring systems requiring high accuracy. The ASIL-B safety features including redundant measurement channels and diagnostic capabilities provide the reliability required for safety systems. The programmable gain amplifiers optimize signal conditioning for different sensor types. The SENT interface is valuable for automotive sensor networks. For high-precision safety-critical sensing, this interface offers excellent performance."
High-precision multi-channel sensor interface with ASIL-B for safety-critical applications
— Jennifer Liu, BeiLuo
Frequently Asked Questions
What sensor types can AC7840-SENSOR interface with?
The AC7840-SENSOR supports multiple sensor types through configurable input channels. Resistive sensors (pressure, temperature, position) are supported with integrated excitation sources. Capacitive sensors are supported with AC excitation and charge measurement. Voltage-output sensors connect directly to the high-impedance inputs. Current-loop sensors (4-20mA) are supported with external sense resistors. The programmable gain amplifiers optimize signal conditioning for each sensor type.
AC7840-SENSOR supports most automotive sensor types. Contact LiTong for specific sensor interface requirements.
What is the effective resolution of the 24-bit ADC?
The AC7840-SENSOR's 24-bit ADC provides effective resolution of approximately 20-22 bits depending on configuration and signal conditions. The effective resolution is limited by noise floor, which depends on gain setting, update rate, and input filtering. At lower update rates with heavy digital filtering, the effective resolution approaches 22 bits. At higher update rates, effective resolution may be 18-20 bits. This is still excellent for high-precision automotive sensor applications.
20-22 bit effective resolution is excellent for high-precision automotive sensing.
What safety features does AC7840-SENSOR include?
The AC7840-SENSOR includes comprehensive safety features for ASIL-B compliance. Features include dual redundant ADC cores with comparison, programmable window comparators for limit checking, independent voltage reference monitoring, and diagnostic SPI interface. The device also includes open-input detection, over-range detection, and internal self-test capabilities. These features enable integration into safety-critical sensor systems with appropriate system-level safety mechanisms.
AC7840-SENSOR safety features support ASIL-B when combined with appropriate system design.
What is the SENT protocol support?
The AC7840-SENSOR includes SENT (Single Edge Nibble Transmission) protocol support for automotive sensor networks. SENT is a cost-effective digital interface widely used for automotive sensors. The device supports SENT protocol with configurable tick time, pause pulse, and data nibbles. Multiple sensor channels can be transmitted sequentially in a single SENT frame. The SENT interface eliminates the need for analog signal wiring, improving noise immunity and reducing wiring complexity.
SENT interface is ideal for automotive sensor networks requiring digital communication.
What is the channel scan rate?
The AC7840-SENSOR supports channel scan rates up to 10k samples per second per channel with all 8 channels active. The scan rate is programmable to balance measurement frequency with power consumption. At maximum scan rate, all 8 channels can be updated at 1kHz. For lower power applications, the scan rate can be reduced to 100Hz or lower. The scan sequence is programmable to prioritize critical sensors.
Configure scan rate based on sensor dynamics and power consumption requirements.