MOTOROLA

SEMICONDUCTOR TECHNICAL DATA

33794 Simplified Application Diagram

33794

This document contains certain information on a new product.

Specifications and information herein are subject to change without notice.

© Motorola, Inc. 2003

Document order number: MC33794/D

Rev 6.0, 04/2003

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ORDERING INFORMATION

Device

Temperature

Package

MC33794DH/R2

-40 to 85°C

44 HSOP

MC33794DWB/R2

-40 to 85°C

54 SOICW-EP

ELECTRIC FIELD

IMAGING DEVICE

Electric Field Imaging Device

The 33794 is intended for applications where noncontact sensing of objects

is desired. When connected to external electrodes, an electric field is created.

The 33794 is intended for use in detecting objects in this electric field. The IC

generates a low-frequency sine wave. The frequency is adjustable by using an

external resistor and is optimized for 120 kHz. The sine wave has very low

harmonic content to reduce harmonic interference.

The 33794 also contains support circuits for a microcontroller unit (MCU) to

allow the construction of a two-chip E-field system.

Features

• Supports up to 9 Electrodes and 2 References

• Shield Driver for Driving Remote Electrodes Through Coaxial Cables

• +5.0 V Regulator to Power External Circuit

• ISO-9141 Physical Layer Interface

• Lamp Driver Output

• Watchdog and Power ON Reset Timer

• Critical Internal Nodes Scaled and Selectable for Measurement

• High-Purity Sine Wave Generator Tunable with External Resistor

DH SUFFIX

CASE 1291

44-LEAD HSOP

DWB SUFFIX

CASE 1390

54-LEAD SOICW-EP

LAMP_OUT

LP_CAP

33794

ISO-9141

SIGNAL

REF_A

REF_B

E1

E2

E9

SHIELD

LEVEL

PWR_MON

LAMP_MON

LAMP_SENSE

ISO_IN

ISO_OUT

WD_IN

RST

LAMP_CTRL

LAMP_GND

TEST

A, B, C, D

DIS_SHIELD

R_OSC

AGND

GND

Analog_IN

Analog_IN

Analog_IN

Analog_IN

Analog_IN

ISO_Tx

ISO_Rx

Watchdog

Reset

Electrode Select

Shield Disable

39 k

Ω

100 pF

10 pF

10 k

Ω

47

µF

0.1

µF

47

µF

10 nF

Indicator

Lamp

Monitor (Optional)

+12 V

1

9

2

GPx

MCU

ISO-9141 Bus

Field Electrodes

4