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AS1716

Datasheet - Application In form atio n

9 Application Information

Figure 13. Application Diagram, minimal requirements

Values of the suggested external components are indicative and need to be characterized for each specific application.

Typical Piezo Sensor:

Resistor from 500k

Ω to 1MΩ

Capacity from 900nF to 1.5µF

Typical wire equivalent circuit:

Capacity to groung from 100pF to 400pF / meter

Capacity between wires strongly depends on type of wires (twisted-pair strongly suggested)

Resistance is typical 50m

Ω / meter @ 20°C

Layout rules

Input Resistors and Capacitors at the inputs should be placed as close as possible to the stonger possible source of disturbances (i.e. the

input connector).

The input lines should be kept as short as possible and routed close to each other.

The filter capacitor (100nF) on supply should be a ceramic type and placed as close as possible to the chip.

VSSA and VDDA lines on PCB should have larger width than other signals to minimize resistance, especially if the 10µF capacitor is not

very close to the chip.

The output line should be kept as short as possible.

Due to

failure

up to 16V

typical

sensor

1k

1k

-

+

Multiple Feedback LP filter

fc ~23kHz typ.

Gain Control

x0.5, x1, x2, x4

INN

INP

GA

GB

100

Ω

to

1k

OUT

µC

12 Bit AD

50k S/s

NC

VSSA

VDDA

100nF 10µF

V 4.5...5.5V

-

+

-

+

VDDA/2

-

+

VDDA/2

+

-

VDDA

VDDA/2

VDDA/2

VDDA/2

AS1716