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L9780：Wide range air fuel sensor control interface

L9780 is an IC designed to interface a variety of wide range air fuel sensors.

The device manages the oxygen pump of the wide range air fuel sensor by means of a voltage controlled current source (VCCS). The reference for the VCCS is generated by a PI controller with external compensation network in order to adapt the device to different sensors. The user can choose between two different networks using the SPI interface. L9780 is fully compatible with most sensors on the market.

The internal timing state machine automatically manages all the operations needed for a right sequencing of the measurement process. All the main time values can be configured by SPI.

L9780 drives also an external FET used to control the sensor heater. The device protects the sensor and all the I/O against shorts and provides the diagnosis by SPI.

Key Features

• Voltage controlled current source (VCCS) pump cell driver with selectable voltage clamp, offset compensation, diagnostic (short to battery) and 2 output channels
• Impedance measurement of reference cell
• 10-bit multiplexed A/D converter
• Scaling amplifier with sample & hold and offset compensation
• Control voltage amplifier with sample & hold and offset compensation
• Synchronous or asynchronous functionality selectable via SPI
• Heater FET driver with diagnostic (short to battery, short to ground, open circuit)
• 4 possible levels for clean current
• SPI with fault detection
• Digital input and outputs compatible with 5 V or 3.3 V voltage supply
• 2 channels available to connect compensation networks
• Short to battery diagnostic on functional ground (pin SR)
• Short to battery/ground diagnostic on voltage from reference cell (pin INRC)
• -5 V internal supply
• 4 MHz internal oscillator
• Package: 48 pin LQFP
• Technology: BCD5s_70 V

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