mc33291l Freescale Semiconductor, Inc, mc33291l Datasheet - Page 11

• Manufacturer Part Number: mc33291l
• Description: Eight-output Switch With Serial Peripheral Interface I/o
• Manufacturer: Freescale Semiconductor, Inc

developed for automotive applications. It is an eight-output
low-side power switch having 8-bit serial control. The 33291L
incorporates SMARTMOS technology having CMOS logic,
bipolar/MOS analog circuitry, and independent state of the
art double diffused MOS (DMOS) power output transistors.
Many benefits are realized as a direct result of using this
mixed technology. A simplified block diagram delineates
33291L in
current for their operation, structured MOS devices, since
they are voltage controlled, require only transient gate
charging current affording a significant decrease in power
consumption. The CMOS capability of the SMARTMOS
process allows significant amounts of logic to be
economically incorporated into the monolithic design.
Additionally, the bipolar/MOS analog circuits embedded
within the updrain power DMOS output transistors monitor
and provide fast, independent protection control functions for
each individual output. All outputs have internal 45 V at 0.5 A
independent output voltage clamps to provide fast inductive
turn-off and transient protection.
output transistors exhibiting very low room temperature
drain-to-source ON resistance values (R
13 V V
currents of less than 2.0 mA (1.0 mA typical) with any
combination of outputs ON are the result of using this mixed
technology and would not be possible with bipolar structures.
To accomplish a comparable functional feature set using a
bipolar structure approach would result in a device requiring
hundreds of milliamperes of internal bias and control current.
This would represent a very large amount of power to be
consumed by the device itself and not available for load use.
serial switch serving as a microcontroller (MCU) bus
expander and buffer with fault management and fault
reporting features. In doing so, the device directly relieves the
MCU of the fault management functions. The 33291L directly
relieves the MCU of the fault management functions. The
33291L directly interfaces to an MCU, operating at system
clock serial frequencies in excess of 3.0 MHz. It uses a
Synchronous Peripheral Interface (SPI) for control and
diagnostic readout.
configuration between an MCU and one 33291L.
Analog Integrated Circuit Device Data
Freescale Semiconductor
The 33291L was conceived, specified, designed, and
Where bipolar devices require considerable control
The 33291L uses high-efficiency updrain power DMOS
During operation, the 33291L functions as an eight output
PWR
Figure
) and dense CMOS control logic. Operational bias
2.
Figure 12
illustrates the basic SPI
DS(ON)
FUNCTIONAL DESCRIPTION
≤ 1.0 Ω at
INTRODUCTION
applications in the computer, telecommunications, and
industrial fields. It is parametrically specified over an input
battery/supply range of 9.0 V to 16 V but is designed to
operate over a considerably wider range of 5.5 V to 26.5 V.
The design incorporates the use of logic level MOSFETs as
output devices. These MOSFETs are sufficiently turned ON
with a gate voltage of less than 5.0 V, thus eliminating the
need for an internal charge pump. Each output is identically
sized and independent in operation. The efficiency of each
output transistor is such that at room temperature with as little
as 9.0 V supply (V
at room temperature is 1.2 Ω (0.9 Ω typical) and increases to
only 2.0 Ω as V
incorporating negative or inverted logic. Whenever an input is
programmed to a logic low state (<1.0 V) the corresponding
low side switched output being controlled will be active low
and turned ON. Conversely, whenever an input is
programmed to a logic high state (>3.0 V), the output being
controlled will be high and turned OFF.
When coupled to an MCU, it receives ON/OFF commands
from the MCU and in return transmits the drain status of the
device’s output switches. Many devices can be daisy-
chained together, forming a larger system, as illustrated in
Figure
port (aside from the required SPI) is required for chip select
to control 32 possible loads.
The circuit can also be used in a variety of other
All inputs are compatible with 5.0 V CMOS logic levels,
One main advantage of the 33291L is the serial port.
Note In this example, only one dedicated MCU parallel
Figure 12. SPI Interface with Microcontroller
13, page 12.
Microcontroller
MC68HCXX
Shift Register
Receive
Parallel
Buffer
Ports
PWR
PWR
is decreased to 5.5 V.
), the maximum R
MOSI
MISO
SCLK
RST
CS
FUNCTIONAL DESCRIPTION
SO
SI
DS(ON)
INTRODUCTION
Shift Register
of an output
33291
Logic
To
33291L
11