L9966 datasheet(8/122 Pages) STMICROELECTRONICS

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Input structure

The L9966 hosts 15 different input channels. These channels can be connected to different types of external

loads, such as switches, sensors or resistors.

The input structure allows down to -3 V negative input voltage:

•

to withstand ground shifts between the ECU ground and the chassis ground where the input signal source is

referenced to

•

limited to the SENT inputs, to withstand the RF noise without clamping effect that could distort the input

signal.

The input structure allows down to -30 V transient on the SENT IO[4:1] pins only if UBSW is no greater than

24 V max. The input protection uses a DPI (Direct Power Injection) filter to avoid rectifying effects in case of HF

disturbance on the line.

On the ECU, the input line must be equipped with a discrete ESD capacitor. The value of this capacitor is 6.8 nF.

Exceptions to this are the SENT inputs (IO1/2/3/4 pins), because the SAE SENT standard allows max. 100 pF,

with an additional 2.2 nF / 560 Ω RC combination. Therefore, SENT inputs have to be additionally protected by

TVS (Transient Voltage Suppressor) on the ECU, if necessary.

L9966

Input structure

DS12459 - Rev 10

page 8/122

L9966 Datasheet(PDF) 8 Page - STMicroelectronics