DocID7791 Rev 7

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L9823

Block diagram and pins description

18

14

OUT2

Output 2

15

SFPD

The Short Fault Protect Disable (SFPD) pin is used to disable the overcurrent latch-OFF. This

feature allows control of incandescent loads where in-rush currents exceed the device's

analog current limits. Essentially the SFPD pin determines whether the L9823 output(s) will

instantly shutdown upon sensing an output short or remain ON in a current limiting mode of

operation until the output short is removed or thermal shutdown is reached. If the SFPD pin is

encountering a load short to supply. If the SFPD pin is grounded, a short circuit will

immediately shutdown only the output affected. Other outputs not having a fault condition will

operate normally.

16

VDD

VDD

17

GND

GND

18

GND

GND

19

GND

GND

20

GND

GND

21

N.C.

Not Connected

22

RESET

The Reset pin is active low and used to clear the SPI shift register and in doing so sets all

output switches OFF. With the device in a system with an MCU; upon initial system power up,

the MCU holds the Reset pin of the device in a logic low state ensuring all outputs to be OFF

until the VDD pin voltages are adequate for predictable operation. After the L9823 is Reset,

the MCU is ready to assert system control with all output switches initially OFF. The Reset pin

is active low and has an internal pull-down incorporated to ensure operational predictability

should the external pull-down of the MCU open circuit. The internal pull-up is to afford safe

and easy interfacing to the MCU. The Reset pin of the L9823 should be pulled to a logic low

state for a duration of at least 160ns to ensure reliable Reset.

23

OUT1

Output 1

24

OUT0

Output 0

Table 2. Pins description (continued)

N#

Pin

Description