Datasheet

NXP Semiconductors 25

10XS3435

6 Functional description

6.1 Introduction

The 10XS3435 is one in a family of devices designed for low-voltage automotive lighting applications. Its four low R

DS(on)

MOSFETs (dual

10 mOhm, dual 35 mOhm) can control four separate 55 W/28 W bulbs and/or Xenon modules.

Programming, control and diagnostics are accomplished using a 16-bit SPI interface. Its output with selectable slew rate improves

electromagnetic compatibility (EMC) behavior. Additionally, each output has its own parallel input or SPI control for pulse-width modulation

(PWM) control if desired. The 10XS3435 allows the user to program via the SPI the fault current trip levels and duration of acceptable

lamp inrush. The device has Fail-safe mode to provide functionality of the outputs in case of MCU damage.

6.2 Functional pin description

6.2.1 Output current monitoring (CSNS)

The Current Sense pin provides a current proportional to the designated HS0 : HS3 output or a voltage proportional to the temperature on

the GND flag. That current is fed into a ground-referenced resistor (2.5 kOhm typical) and its voltage is monitored by an MCU's A/D. The

output type is selected via the SPI. This pin can be tri-stated through the SPI.

6.2.2 Direct inputs (IN0, IN1, IN2, IN3)

Each IN input wakes the device. The IN0 : IN3 high-side input pins are also used to directly control HS0 : HS3 high-side output pins. In case

of the outputs are controlled by PWM module, the external PWM clock is applied to IN0 pin. These pins are to be driven with CMOS levels,

and they have a passive internal pull-down, R

DWN

6.2.3 Fault status (FS)

This pin is an open drain configured output requiring an external pull-up resistor to V

for fault reporting. If a device fault condition is

detected, this pin is active LOW. Specific device diagnostics and faults are reported via the SPI SO pin.

6.2.4 Wake

The wake input wakes the device. An internal clamp protects this pin from high damaging voltages with a series resistor (10 kOhm typ).

This input has a passive internal pull-down, R

DWN

6.2.5 Reset (RST)

The reset input wakes the device. This is used to initialize the device configuration and fault registers, as well as place the device in a low-

current sleep mode. The pin also starts the watchdog timer when transitioning from logic [0] to logic

[1]. This pin has a passive internal

pull-down, R

DWN

6.2.6 Chip select (CS)

The CS pin enables communication with the master microcontroller (MCU). When this pin is in a logic [0] state, the device is capable of

transferring information to, and receiving information from, the MCU. The 10XS3435 latches in data from the Input Shift registers to the

addressed registers on the rising edge of

CS. The device transfers status information from the power output to the Shift register on the

falling edge of

CS. The SO output driver is enabled when CS is logic [0]. CS should transition from a logic [1] to a logic [0] state only when

SCLK is a logic

[0]. CS has an active internal pull-up from V

, I