Freescale Semiconductor
Advance Information
Document Number: MC33972
Rev 15, 8/2008
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 5.5V
≤
V
PWR
≤
26V
Switch input voltage range -14V to V
PWR
, 40V Max
Interfaces directly to MPU using 3.3V / 5.0V SPI protocol
Selectable wake-up on change of state
Selectable wetting current (16mA or 2.0mA)
8 programmable inputs (switches to battery or ground)
14 switch-to-ground inputs
Typical standby current - V
PWR =
100μA and V
DD
= 20μA
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
V
BAT
SP0
SP1
V
BAT
SP7
SG0
SG1
SI
SCLK
CS
SO
INT
AMUX
GND
V
BAT
POWER SUPPLY
LVI
Temperature
Range (T
A
)
Package
-40°C to 125°C
32 SOICW
32 SOICW EP
33972
VPWR
VDD
WAKE
VDD
ENABLE
MCU
MOSI
SCLK
CS
MISO
INT
AN0
WATCHDOG
RESET
SG12
SG13
Figure 1. 33972 Simplified Application Diagram
* This document contains certain information on a new product.
Specifications and information herein are subject to change without notice.
© Freescale Semiconductor, Inc., 2007-2008. All rights reserved.
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
