33984B datasheet(22/38 Pages) FREESCALE

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Analog Integrated Circuit Device Data

Freescale Semiconductor

33984

FUNCTIONAL DEVICE OPERATION

GROUND DISCONNECT PROTECTION

In the event the 33984 ground is disconnected from load

ground, the device protects itself and safely turns OFF the

output regardless the state of the output at the time of

disconnection. A 10 k resistor needs to be added between

the wake pin and the rest of the circuitry in order to ensure

that the device turns off in case of ground disconnect, and to

prevent this pin from exceeding its maximum ratings

Table 8. Device Behavior in Case of Under-voltage

High Side

Switch

(VPWR Battery

Voltage)

∗∗

State

UV Enable

IN = 0

(Falling VPWR)

UV Enable

IN = 0

(Rising VPWR)

UV Enable

∗∗∗ = 1

(Falling VPWR)

UV Enable

∗∗∗ = 1

(Rising VPWR)

UV Disable

IN = 0

(Falling or

Rising VPWR)

UV Disable

∗∗∗ = 1

(Falling or

Rising VPWR)

VPWR >

VPWRUV

Output State

OFF

FS State

SPI Fault

Bit

1 until next read

VPWRUV >

VPWR >

UVPOR

Output State

OFF

FS State

SPI Fault

Bit

UVPOR >

VPWR > 2.5 V

∗

Output State

OFF

FS State

SPI Fault

Bit

1 until next read

1 until next read 1 until next read

2.5 V > VPWR >

0 V

Output State

OFF

FS State

SPI Fault

Bit

1 until next read 1 until next read 1 until next read 1 until next read

Comments

UV fault is

not latched

UV fault is

not latched

UV fault

is latched

∗ Typical value; not guaranteed

∗∗ While VDD remains within specified range.

∗∗∗ = IN is equivalent to IN direct input or IN_spi SPI input.

33984B Datasheet(PDF) 22 Page - Freescale Semiconductor, Inc

33984B Datasheet(HTML) 22 Page - Freescale Semiconductor, Inc

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