Multiple Switch Detection Interface with Suppressed Wake-up0 pages

Freescale Semiconductor
Technical Data

Document Number: MC34972
Rev. 1.0, 9/2013

Multiple Switch Detection
Interface with Suppressed
Wake-up

34972
MULTIPLE SWITCH
DETECTION INTERFACE

The 34972 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 34972 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 34972 ideal for industrial products requiring low sleep-state
currents. This device is powered by SMARTMOS technology.

EW SUFFIX (Pb-FREE)
98ARH99137A
32-PIN SOICW

ORDERING INFORMATION

Features
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•
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EK SUFFIX (Pb-FREE)
98ASA10556D
32-PIN SOICW EP

Designed to operate 5.5 V VPWR 26 V
Switch input voltage range -14 V to VPWR, 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)
Eight programmable inputs (switches to supply or ground)
14 switch-to-ground inputs
Typical standby current - VPWR = 100 A and VDD = 20 A
Active interrupt (INT) on change-of-switch state

Device
MC34972ATEW/R2

Temperature
Range (TA)

Package
32 SOICW

-40 to 85 °C

MC34972ATEK/R2

32 SOICW EP

VDD
VPWR

VPWR

34972
SP0
SP1

VPWR

VPWR

POWER SUPPLY

LVI

VDD
ENABLE

VDD
SP7

SG0
SG1
SG12

SG13

WAKE

SI
SCLK
CS
SO
INT
AMUX

MCU

MOSI
SCLK
CS
MISO
INT
AN0

GND

Figure 1. 34972 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., 2013. All rights reserved.

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