Eight Output Switch with Serial
Peripheral Interface I/O
Document Number: MC33298
Rev. 5.0, 10/2006
The 33298 is a smart eight-output low-side power switch. It is a
versatile device incorporating an 8-bit serial-in shift register to control
an 8-bit parallel output latch providing control of eight independent
"ON/OFF" output switches. Applications include the control of
solenoids, relays, lamps, small DC-motors, and other moderate
current loads (1.0 – 3.0 A).
The 33298 interfaces directly with a microcontroller to control
various inductive or incandescent loads. Input control is fast. Data
rates are guaranteed to 2.0 MHz but the device is capable of rates to
8.5 MHz @ 25°C.
Each output uses high-efficiency MOSFET power transistors
configured with open drains. Each low "ON" resistance output (0.4 Ω
RDS(ON) @ 25°C) is capable of sinking up to 3.0 A of transient current.
On a continuous basis, each output can simultaneously (with all
outputs "ON") handle 0.5 A of current when the device is soldered onto
a typical PC board. Higher output currents are dependent on the
number of outputs simultaneously "ON". The circuit's innovative
monitoring and protection features include very low standby current.
EG SUFFIX (PB-FREE)
• Designed to Operate Over Wide Supply Voltages of 5.5 to 26.5 V
• Interfaces to Microprocessor Using 8-Bit SPI I/O Protocol up to
-40°C to 125°C
• 1.0 A Peak Current Outputs with Maximum RDS(on) of 1.6 Ω
at TJ - 150°C
• Outputs Current Limited to Accommodate In-rush Currents Associated with Switching Incandescent Loads
• Output Voltages Clamped to 53 V During Inductive Switching
• Maximum Sleep Current (IPWR) of 25 µA
• Maximum of 4.0 mA IDD During Operation
• Pb-Free Packaging Designated by Suffix Code EG
VPWR OP 0
SFPD OP 1
VDD OP 2
Figure 1. 33298 Simplified Application Diagram
Freescale Semiconductor, Inc. reserves the right to change the detail specifications, as
may be required, to permit improvements in the design of its products.
© Freescale Semiconductor, Inc., 2006. All rights reserved.