Freescale Semiconductor
Technical Data
Document Number: MC33972
Rev. 16.0, 10/2009
Multiple Switch Detection
Interface with Suppressed
Wake-up
The 33972 Multiple Switch Detection Interface with suppressed
wake-up is designed to detect the closing and opening of up to 22
switch contacts. The switch status, either open or closed, is transferred
to the microprocessor unit (MCU) through a serial peripheral interface
(SPI). The device also features a 22-to-1 analog multiplexer for reading
inputs as analog. The analog input signal is buffered and provided on
the AMUX output pin for the MCU to read.
The 33972 device has two modes of operation, Normal and Sleep.
Normal mode allows programming of the device and supplies switch
contacts with pull-up or pull-down current as it monitors switch change
of state. The Sleep mode provides low quiescent current, which makes
the 33972 ideal for automotive and industrial products requiring low
sleep-state currents.
Features
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Designed to operate 5.5 V
≤
V
PWR
≤
26 V
Switch input voltage range -14 V to V
PWR
, 40 V Max
Interfaces directly to MPU using 3.3 V / 5.0 V SPI protocol
Selectable wake-up on change of state
Selectable wetting current (16 or 2.0 mA)
8 programmable inputs (switches to battery or ground)
14 switch-to-ground inputs
Typical standby current - V
PWR =
100
μA
and V
DD
= 20
μA
Active interrupt (
INT
) on change-of-switch state
Pb-free packaging designated by suffix code EW
Exposed pad packaging designated by suffix code EK
33972/A/T
MULTIPLE SWITCH
DETECTION INTERFACE
DWB SUFFIX
EW SUFFIX (Pb-FREE)
98ARH99137A
32-PIN SOICW
EK SUFFIX (Pb-FREE)
98ASA10556D
32-PIN SOICW EP
ORDERING INFORMATION
Device
MC33972DWB/R2
MC33972EW/R2
MCZ33972EW/R2
MCZ33972AEW/R2
MC33972TDWB/R2
MC33972TEW/R2
MCZ33972TEW/R2
MCZ33972AEK/R2
VDD
VBAT
SP0
SP1
VBAT
SP7
SG0
SG1
SG12
SG13
SI
SCLK
CS
SO
INT
AMUX
GND
VBAT
POWER SUPPLY
Temperature
Range (T
A
)
Package
-40°C to 125°C
32 SOICW
32 SOICW EP
33972
VPWR
VDD
WAKE
VDD
LVI
ENABLE
MOSI
SCLK
CS
MISO
INT
AN0
MCU
WATCHDOG
RESET
Figure 1. 33972 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., 2009. All rights reserved.
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
