33988 Datasheet, PDF (21/34 Pages) Freescale Semiconductor, Inc – Dual Intelligent High-current Self-protected Silicon High Side Switch (8.0mΩ)

FUNCTIONAL DEVICE OPERATION
GROUND DISCONNECT PROTECTION
In the event the 33988 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 10K 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 to exceed its maximum ratings
Table 7. Device Behavior in Case of Under-voltage
High Side
Switch
(VPWR Battery
Voltage) ∗∗
State
UV Enable
UV Enable
UV Enable
UV Enable
IN = 0
IN = 0
IN∗∗∗ = 1
IN∗∗∗ = 1
(Falling VPWR) (Rising VPWR) (Falling VPWR) (Rising VPWR)
UV Disable
IN = 0
(Falling or
Rising VPWR)
UV Disable
IN∗∗∗ = 1
(Falling or
Rising VPWR)
VPWR >
Output State
OFF
OFF
ON
OFF
VPWRUV
FS State
1
1
1
0
SPI Fault
0
1 until next read
0
1
Register UVF
Bit
VPWRUV >
VPWR >
UVPOR
Output State
FS State
SPI Fault
Register UVF
Bit
OFF
0
1
OFF
0
1
OFF
0
1
OFF
0
1
UVPOR >
Output State
OFF
VPWR > 2.5V ∗
FS State
1
OFF
1
OFF
1
OFF
1
SPI Fault
1 until next read
1
1 until next read 1 until next read
Register UVF
Bit
2.5V > VPWR > Output State
0V
FS State
OFF
1
OFF
1
OFF
1
OFF
1
SPI Fault
Register UVF
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.
OFF
1
0
OFF
1
0
OFF
1
0
OFF
1
0
ON
1
0
ON
1
0
ON
1
0
OFF
1
0
Analog Integrated Circuit Device Data
Freescale Semiconductor
33988
21