L9780 Wide range air fuel sensor control interface Datasheet - production data 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) * 3*36 -5 V internal supply LQFP48 4 MHz internal oscillator Package: 48 pin LQFP Technology: BCD5s 70 V Features Description Voltage controlled current source (VCCS) L9780 is an IC designed to interface a variety of pump cell driver with selectable voltage clamp, wide range air fuel sensors. offset compensation, diagnostic (short to battery) and 2 output channels The device manages the oxygen pump of the wide range air fuel sensor by means of a voltage Impedance measurement of reference cell controlled current source (VCCS). The reference 10-bit multiplexed A/D converter for the VCCS is generated by a PI controller with Scaling amplifier with sample & hold and offset external compensation network in order to adapt compensation the device to different sensors. The user can choose between two different networks using the Control voltage amplifier with sample & hold SPI interface. L9780 is fully compatible with most and offset compensation sensors on the market. Synchronous or asynchronous functionality selectable via SPI The internal timing state machine automatically manages all the operations needed for a right Heater FET driver with diagnostic (short to sequencing of the measurement process. All the battery, short to ground, open circuit) main time values can be configured by SPI. 4 possible levels for clean current L9780 drives also an external FET used to control SPI with fault detection the sensor heater. The device protects the sensor Digital input and outputs compatible with 5 V or and all the I/O against shorts and provides the 3.3 V voltage supply diagnosis by SPI. Table 1. Device summary Order code Package Packing L9780 LQFP48 Tray L9780TR LQFP48 Tape and reel November 2014 DocID026356 Rev 3 1/56 This is information on a product in full production. www.st.comContents L9780 Contents 1 Pin description . 7 2 Operating conditions 9 2.1 Maximum ratings 9 2.2 Absolute maximum ratings . 9 2.3 Operating temperature range 10 3 Block diagram . 11 4 Main functionalities . 12 4.1 Power supplies . 12 4.2 Pin protection 12 4.3 Internal references 12 4.4 Power on reset . 13 4.5 Pin INRC functionalities: INRC amplifier, clean currents, pull-down current 13 4.6 Pin RCT1 RCT2 functionalities: RCT2 amplifier, RCT1 switch, RCT1 band-gap switch 14 4.7 Pin C1A, C2A, C1B, C2B, C3 functionalities: compensation network connection 14 4.8 Pin FV, FVOUT functionalities: FVOUT amplifier . 15 4.9 Pin TG1, TG2, OUT1, OUT2, SNS functionalities: the VCCS . 15 4.10 Pin PG1, PG2, SR functionalities . 20 4.11 Analog to digital conversion . 21 4.12 Timing state machine 22 4.13 Pin HD, HG functionalities: heater FET driver and diagnostic . 25 5 Diagnostic 26 5.1 Sensor short to battery . 26 Actions .26 5.2 INRC pin short to ground . 26 Actions .27 5.3 SNS pin short to ground 27 Actions .27 Application note 27 5.4 Heater diagnostic . 27 5.4.1 Heater short to battery 28 2/56 DocID026356 Rev 3