L9613

Functional description

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Functional description

The L9613 is a monolithic bus driver designed to provide bidirectional serial communication

in automotive applications.

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.

All VBat bus defined inputs LI and K have supply voltage dependent thresholds together with

sufficient hysteresis to suppress line spikes. These pins are protected against over voltages,

shorts to GND and VS and can also be driven beyond VS and GND. These features are also

given for TX, RX and LI only taking into account the behavior of the internal pull up

resistances. The thermal shut down function switches OFF the K output if the chip

temperature increases above the thermal shut down threshold. To reactivate K again the

chip temperature must decrease below the K switch ON temp. To achieve no fault for VS

intervillage conditions the outputs will be switched OFF and stay at high impedance. The

device is also protected against reverse battery condition. During lack of VS or GND all pins

shows high impedance characteristic. To realize a lack of the VS related bus line LI and K

the outputs LO and RX shows defined ON status. Suppressing all 4 classes of "Schaffner"

signals (Schaffner 1; 2; 3a,b; 4) all pins can be load with short energy pulses of max.

0.2mJ. All these features together with a high possible baud rate >130Kbaud, controlled

output slopes for low EMI, a wide power supply voltage range and a real standby function

with zero power consumption ISSB typ

1µA during system de powering VCC  0.5V make

this device high efficient for automotive bus system.

After wake up of the system from SB condition the first output signal will have an additional

delay time tdtyp 5µs.

The typical output voltage behavior for the K, LO, RX outputs as a function of the output

current is shown in Figure 4. Figure 5 shows a waveform of the output signal when the low

level changes from RON

IOUT to IOUT 2 RON + UBE state. This variation occurs due to too low

output current or after a negative transient forced to the output or to the supply voltage line.