Freescale Semiconductor
Advance Information
Document Number: MC33975
Rev 9.0, 8/2008
Multiple Switch Detection
Interface with Suppressed
Wake-up and 32mA Wetting
Current
The 33975 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 33975 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 the switch
change of state. The Sleep Mode provides low quiescent current,
which makes the 33975 ideal for automotive and industrial products
requiring low sleep state currents.
Improvements are a programmable interrupt timer for Sleep Mode
that can be disabled, switch detection currents of 32mA and 4.0mA for
switch-to-ground inputs, and an interrupt bit that can be reset.
Features
Designed to operate from 5.5V
≤
V
PWR
≤
28V
Switch input voltage: (33975: -14 to 38V) (33975A: -14 to 40V)
Interfaces to microprocessor using 3.3V/5.0V SPI protocol
Selectable wake-up on change of state
14 switch-to-ground inputs
8 programmable inputs (switches to battery or ground)
Selectable wetting current (32mA or 4.0mA for switch-to-ground
inputs)
• Sleep State current V
PWR
100
μA,
Vdd 20
μA
• Pb-free packaging designated by suffix code EK
•
•
•
•
•
•
•
33975
33975A
MULTIPLE SWITCH
DETECTION INTERFACE WITH
SUPPRESSED WAKE-UP
EK SUFFIX (PB-FREE)
98ASA10556D
32-PIN SOICW EP
ORDERING INFORMATION
Device
MC33975EK/R2
MCZ33975EK/R2
MCZ33975AEK/R2
-40°C to 125°C
32 SOICW-EP
Temperature
Range (T
A
)
Package
VDD
V
BAT
SP0
SP1
V
BAT
SP7
SG0
SG1
SI
SCLK
CS
SO
INT
AMUX
GND
V
BAT
POWER SUPPLY
LVI
33975
VPWR
VDD
WAKE
VDD
ENABLE
SG12
SG13
MOSI
SCLK
CS
MISO
INT
AN0
MCU
WATCHDOG
RESET
Figure 1. 33975 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., 2005 - 2007. All rights reserved.
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