L9637 Monolithic bus driver with ISO 9141 interface Features ■ Operating power supply voltage range 4.5 V VS 36 V (40 V for transients) Reverse supply (battery) protected down to VS -24 V Standby mode with very low current consumption ISSB 1 mA @ VCC 0.5 V Low quiescent current in off condition ISOFF = 120 µA Bidirectional K-I/O pin with supply voltage dependent input threshold High input impedance for open VS or GND connection Overtemperature shut down function Selective to K-I/O pin Defined output ON status of LO or RX for open LI or K inputs Defined K output OFF for TX input open Wide input and output voltage range -24 V VK VS Integrated pull up resistors for TX, RX and LO K output current limitation, typ. IK = 60 mA Defined OFF output status in undervoltage condition and VS or GND interruption Controlled output slope for low EMI Description The L9637 is a monolithic integrated circuit containing standard ISO 9141 compatible interface functions. Device summary Order code 1. Device in ECOPACK® package (see Section 4: Package information on page 13).

Block diagram and pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 1.2 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Block diagram and pin description Block diagram and pin description Block diagram Figure 1. Block diagram Supply voltage Stabilized voltage supply Input for K as output

Electrical specification Electrical specification Absolute maximum ratings Table 3. Absolute maximum ratings (No damage or latch) Stabilized voltage Supply voltage ISO transients t = 400 ms Supply voltage transient Max. ESD voltages are ±2kV with human body model C = 100pF, R = 1.5k corresponds to maximum energy dissipation 0.2mJ according to MIL883C. Thermal data Thermal data Temperature K shutdown switch on threshold Temperature K shutdown switch off threshold Thermal steady state junction to ambient resistance Electrical characteristics The electrical characteristics are valid within the below...

Electrical specification Table 5. Electrical characteristics (continued)

Electrical specification Table 5. Electrical characteristics (continued) Test condition Input voltage HIGH state LO output status HIGH 0.55VS 4.5 V VS 18 V 12 LO output status HIGH 18 V < VS Input threshold hysteresis VLIhigh - VLIlow Input current Internal output capacities fLI-LO fK-RX fTX-k Transmission frequency trLI-LO trK-RX trTX-K Rise time tfLI-LO tfK-RX tfTX-K Fall time tOFF,LI-LO tOFF,K-RX tOFF,TX-K tON,LI-LO tON,K-RX tON,TX-K 9 V < VS < 16 V (external loads) RKO = 510 , CK 1.3 nF in active mode see Figure 5 for the definition of tr, tf see Figure 3 9 V < VS < 16 V (external loads)...

Electrical specification Figure 3. Input to output timings and output pulse shape VI

Electrical specification Figure 4.

Functional description Functional description The L9637 is a monolithic bus driver designed to provide bidirectional serial communication in automotive diagnostic applications according to the specification "Diagnostic Systems ISO9141". The device provides a bidirectional link, called K, to the VBat related diagnosis bus. It also includes a separate comparator L which is also able to be linked to the VBat bus. The input TX and output RX of K are related to VCC with her integrated pull up resistances. Also the L comparator output LO has a pull up resistance connected to VCC. The maximum external...

Functional description Figure 5. Typical timing for mode transitions

Functional description Figure 6. Output signal shape related to output current

Functional description Figure 8. Input power vs. frequency diagram

Package information Package information In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: www.st.com. ECOPACK® is an ST trademark. Figure 10. SO8 mechanical data and package dimensions mm OUTLINE AND MECHANICAL DATA Notes: 1. Dimensions D does not include mold flash, protrusions or gate burrs. Mold flash, potrusions or gate burrs shall not exceed 0.15mm in total (both side). 2. Dimension “E1” does not...

Revision history Revision history Table 6. Document revision history Initial release. Document reformatted. Added Table 1: Device summary on page 1. Updated Section 4: Package information on page 13. Updated the values of “stabilized voltage” and “transmission frequency” parameters on Table 5: Electrical characteristics. Updated disclaimer.

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