33981 datasheet(12/37 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

33981

FUNCTIONAL DESCRIPTION

INTRODUCTION

FUNCTIONAL DESCRIPTION

INTRODUCTION

The 33981 is a high-frequency self-protected silicon

4.0 m

Ω RDS(ON) high side switch used to replace

electromechanical relays, fuses, and discrete devices in

power management applications. The 33981 can be

controlled by pulse-width modulation (PWM) with a frequency

up to 60 kHz. It is designed for harsh environments, and it

includes self-recovery features.

The 33981 is suitable for loads with high inrush current, as

well as motors and all types of resistive and inductive loads.

A dedicated parallel input is available for an external low side

control with protection features and cross-conduction

management.

FUNCTIONAL PIN DESCRIPTIONS

OUTPUT CURRENT MONITORING (CSNS)

This pin is used to output a current proportional to the high

side OUT current and is used externally to generate a

ground-referenced voltage for the microcontroller (MCU) to

monitor OUT current.

TEMPERATURE FEEDBACK (TEMP)

This pin reports an analog value proportional to the

temperature of the GND flag (pin 13). It is used by the MCU

to monitor board temperature.

ENABLE [ACTIVE HIGH] (EN)

This is an input used to place the device in a low-current

Sleep Mode. This pin has an active passive internal pull-

down.

INPUT HIGH SIDE (INHS)

The input pin is used to directly control the OUT. This input

has an active internal pull-down current source and requires

CMOS logic levels.

FAULT STATUS (FS)

This pin is an open drain-configured output requiring an

external pull-up resistor to VDD (5.0 V) for fault reporting.

When a device fault condition is detected, this pin is active

LOW.

INPUT LOW SIDE (INLS)

This input pin is used to directly control an external low

side N-channel MOSFET and has an active internal pull-

down current source and requires CMOS logic levels. It can

be controlled independently of the INHS depending of CONF

pin.

CONFIGURATION INPUT (CONF)

This input pin is used to manage the cross-conduction

between the internal high side N-channel MOSFET and the

external low side N-channel MOSFET. The pin has an active

internal pull-up current source. When CONF is at 0 V, the

two MOSFETs are controlled independently. When CONF is

at VDD 5.0 V, the two MOSFETs cannot be on at the same

time.

LOW SIDE OVERLOAD (OCLS)

This pin sets the VDS protection level of the external low

side MOSFET. This pin has an active internal pull-up current

source. It must be connected to an external resistor.

DRAIN LOW SIDE (DLS)

This pin is the drain of the external low side N-channel

MOSFET. Its monitoring allows protection features: low side

short protection and VPWR short protection.

LOW SIDE GATE (GLS)

This pin is an output used to drive the gate of the external

low side N-channel MOSFET.

SLEW RATE CONTROL (SR)

A capacitor connected between this pin and ground is

used to control the output slew rate.

BOOTSTRAP CAPACITOR (CBOOT)

A capacitor connected between this pin and OUT is used

to switch the OUT in PWM mode.

GROUND (GND)

This pin is the ground for the logic and analog circuitry of

the device.

POSITIVE POWER SUPPLY (VPWR)

This pin connects to the positive power supply and is the

source input of operational power for the device. The VPWR

pin is a backside surface mount tab of the package.

OUTPUT (OUT)

Protected high side power output to the load. Output pins

must be connected in parallel for operation.

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