Freescale Semiconductor
Advance Information
Document Number: MC33972
Rev. 9.0, 4/2007
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 pullup or pulldown 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 mA 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
33972
33972A
MULTIPLE SWITCH
DETECTION INTERFACE
DWB SUFFIX
EW SUFFIX (Pb-FREE)
98ARH99137A
32-PIN SOICW
ORDERING INFORMATION
Device
MC33972DWB/R2
MC33972EW/R2
MCZ33972AEW/R2
-40°C to 125°C
32 SOICW
Temperature
Range (T
A
)
Package
VDD
VBAT
VBAT
SP0
SP1
VBAT
SP7
Power Supply
LVI
VDD
VDD
WAKE
SI
SCLK
CS
SO
INT
AMUX
MOSI
SCLK
CS
MISO
INT
AN0
Enable
Watchdog
Reset
MCU
33972
VPWR
SG0
SG1
SG12
SG13
GND
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. All rights reserved.
FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
