33997 datasheet(3/20 Pages) FREESCALE

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MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA

33997

PIN FUNCTION DESCRIPTION

Pin Name

Description

VKAMOK

Keep-Alive Output Monitoring. This pin is an "open-drain" output that will be used with a discrete pull-up resistor

to VKAM. When the supply voltage to the 33997 is disconnected or lost, the VKAMOK signal goes low.

KA_VPWR

Keep Alive Power Supply Pin. This supply pin is used in modules that have both direct battery connections and

ignition switch activated connections.

CRES

Reservoir Capacitor. This pin is tied to an external "reservoir capacitor" for the internal charge pump.

VPWR

Power Supply Pin. Main power input to the IC. This pin is directly connected to the switching regulator power

MOSFET. In automotive applications this pin must be protected against reverse battery conditions by an

external diode.

5–8

GND

Ground of the integrated circuit.

VSW

Internal P-Channel Power MOSFET Drain. VSW is the "switching node" of the voltage buck converter. This pin

is connected to the VPWR pin by an integrated p-channel MOSFET.

PWROK

Power OK Reset Pin. This pin is an "open-drain" output that will be used with a discrete pull-up resistor to

VKAM, VDDH, or VDDL. When either VDDH or VDDL output voltage goes out of the regulation limits this pin is

pulled down.

FBKB

Step-Down Switching Regulator Feedback Pin. The FBKB pin is the VDDH feedback signal for the switching

regulator.

VSUM

Error Amplifier "Summing Node". The VSUM pin is connected to the inverting input of the error amplifier. This

node is also the "common" point of the integrated feedback resistor divider.

DRVL

Drive for VDDL (3.3 V) Regulator. The DRVL pin drives the base of an external NPN pass transistor for the

VDDL linear post regulator. The collector of the VDDL pass transistor is connected to VDDH. An example of a

suitable pass transistor is BCP68.

FBL

Feedback for VDDL (3.3 V) Regulator. The FBL pin is the voltage feedback sense signal from the VDDL (3.3 V)

linear post regulator.

VDDH

VDDH is an input supply pin providing power for the buffered sensor supplies and the drive circuitry for the 3.3 V

linear power regulator. The VDDH pin is supplied from the switching regulator output, capable of providing 5.0 V

@ 1400 mA total output current.

VREF2

Sensor Supply #2 Output. The VREF2 pin is sensor supply output #2.

17–20

GND

Ground of the integrated circuit.

VREF1

Sensor Supply #1 Output. The VREF1 pin is sensor supply output #1.

VKAM

GND

VREF2

VDDH

FBL

DRVL

SNSEN

VREF1

VKAMOK

GND

VSW

PWROK

VSUM

KA_VPWR

CRES

VPWR

FBKB

Freescale Semiconductor, Inc.

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