FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
POWER SUPPLY
SELF-PROTECTED
HIGH SIDE SWITCH
MCU INTERFACE AND
OUTPUT CONTROL
HS [0:1]
SPI INTERFACE
MCU
INTERFACE
PARALLEL CONTROL
INPUTS
load disconnections and short-circuit fault conditions. The
HS[0:1] outputs are actively clamped during a turn-off of
inductive loads.
POWER SUPPLY
The 33984 is designed to operate from 4.0 to 28 V on the
VPWR pin. Characteristics are provided from 6.0 to 20 V for
the device. The VPWR pin supplies power to internal
regulator, analog, and logic circuit blocks. The VDD supply is
used for Serial Peripheral Interface (SPI) communication in
order to configure and diagnose the device. This IC
architecture provides a low quiescent current sleep mode.
Applying VPWR and VDD to the device will place the device in
the Normal mode. The device will transit to Fail-safe mode in
case of failures on the SPI (watchdog timeout).
MCU INTERFACE AND OUTPUT CONTROL
In Normal mode, the loads are controlled directly from the
MCU through the SPI. With a dedicated SPI command, it is
possible to independently turn on and off several loads that
are PWM’d at the same frequency, and duty cycles with only
one PWM signal. An analog feedback output provides a
current proportional to each load current. The SPI is used to
configure and to read the diagnostic status (faults) of the high
side output. The reported fault conditions are: open load,
short-circuit to ground (OCLO-resistive and OCHI-severe
short-circuit), thermal shutdown, and under/over-voltage.
HIGH SIDE SWITCH: HS[0:1]
Those pins are the high side outputs controlling multiple
automotive loads with high inrush current, as well as motors
and all types of resistive and inductive loads. This N-channel
MOSFET with 4.0 mΩ RDS(ON), is self-protected and each
N-channel presents extended diagnostics in order to detect
In Fail-safe mode, the loads are controlled with dedicated
parallel input pins. The device is configured in default mode.
33984
Analog Integrated Circuit Device Data
Freescale Semiconductor
19
FREESCALE [ Freescale ]
