Document Number: MC33884

Rev. 4.0, 11/2006

Freescale Semiconductor

Technical Data

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., 2006. All rights reserved.

Switch Monitor Interface

The 33884 Switch Monitor Interface is a monolithic silicon integrated

circuit (IC) to perform switch monitoring functions. The device provides

efficient interface between electrical switches and low voltage

microprocessors. The 33884 supplies switch contact pull-up and pull

down current while monitoring the input voltage level. All inputs are

protected for transients when implemented with an appropriate static

discharge capacitor used on the inputs.

There are four modes of operation: Sleep, Normal, Polling, and

Polling + INT Timer.

The Polling and Timer modes are similar, except the Timer mode

has the addition of an interrupt that is sent to the microprocessor if a

switch is sensed closed, or upon the internal interrupt timer times out.

An interrupt is ultimately sent to the microprocessor. All modes of

operation are easily programmed via the Serial Peripheral Interface

(SPI) control.

Features

• Input Voltage Range: -14 V to 40 V

• Interface Directly to Microprocessors Using SPI Protocol

• Wake Up on Change of Monitored Switch Status

• Programmable Wetting Current

• Four Switch-to-Ground Switches

• Six (Fixed Function) Inputs Monitoring Six Switch-to-Ground

Switches

• Two (Fixed Function) Inputs Monitoring Two Switch-to-Battery Switches

• Quiescent Current in Sleep Mode < 10 µA

• Reset Input Defaults the Device to Sleep Mode

• Pb-Free Packaging Designated by Suffix Code EG

Figure 1. 33884 Simplified Application Diagram

SWITCH MONITOR INTERFACE

DW SUFFIX

EG (PB-FREE) SUFFIX

98ASB42344B

24-PIN SOICW

33884

ORDERING INFORMATION

Device

Temperature

Package

MC33884DW/R2

-40°C to 105°C

24 SOICW

MCZ33884EG/R2

6 GND

Sense Inputs

4 GND / VPWR

Sense Inputs

2 VPWR

Sense Inputs

33884

VDD

MOSI

MISO

CLK

GND

VDD

VPWR

MCU

SG1

SG2

SG3

SG4

SG5

SG6

SP1

SP2

SP3

SP4

VDD

CS

SI

SO

SCLK

INT

SYNC

MASL

RESET

GND

VBG

SB1

SB2

VPWR

CS

INT

RESET