High Performance Automotive Sonar Intrusion – Data Sheet

AS8412

March 2001

Page 13 of 14

Application Circuits

The AS8412 is designed to provide a flexible utilization, so many application circuits are possi-

ble. Only two of them are presented.

The Application Circuit I of Fig. 8a is suitable to be used in a microcontroller-based alarm sys-

tem. The 40-kHz clock is synthesized by the microcontroller, that also controls the digital sen-

sitivity. By having access to all the signalling outputs, the alarm system can be programmed to

signalize any combination of the disturbances detectable by the AS8412.

This arrangement uses a minimum number of components to implement an intrusion detector.

TX1

OSCIN

OSCOUT

VCAP

AVDD

AGND

RXGND

RX

SEL4OK

ALEN

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

TX2

ALARM

WARN

LED

GND

VDD

TP

SAS

SENS1

SENS0

UT1

40kHz

from

µ-Processor

N.C.

C1

VDD

C2

100n

R1

100k

C4

100n

UT2

To

µ-Processor

Programmable

Sensitivity

(Digital)

SAS Control

N.C.

VDD

VDD

C3

100n

Fig. 8a - Application Circuit I

TX1

OSCIN

OSCOUT

VCAP

AVDD

AGND

RXGND

RX

SEL4OK

ALEN

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

TX2

ALARM

WARN

LED

GND

VDD

TP

SAS

SENS1

SENS0

R2

100k

C1

100p

UT2

VDD

Programmable

Sensitivity

(Digital)

N.C.

VDD

C5

100n

VDD

VDD

N.C.

C2

100p

C3

R3

C6

100n

C4

100n

UT1

CR1

R1

D1

To Control Unit

C7

Fig. 8b - Application Circuit II