3

Fig.3 SINAD vs Input Level – Typical Values

Application Notes

INPUT LEVEL dB

SINAD (dB)

30

40

50

60

-40

-30

-20

-10

0

10.0

25.0

75.0

250.0

775.0

1000.0

1730.0

-17

110.0

mVrms

7.0

Input Frequency = 1.0kHz

Input Level 0dB ref = 775mVrms

Ch1 2, 3 or 4 Gain Set to 0dB

V

DD

V

DD

V

SS

V

SS

V

BIAS

V

SS

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

FX019

SERIAL CLOCK INPUT

CONTROL DATA INPUT

CHIP SELECT

CHANNEL 1 OUTPUT

CHANNEL 2 OUTPUT

CHANNEL 3 OUTPUT

CHANNEL 4 OUTPUT

CHANNEL 1 INPUT

CHANNEL 2 INPUT

CHANNEL 3 INPUT

CHANNEL 4 INPUT

LOAD/LATCH

LOAD/LATCH

Application Recommendations

(f)

Analogue tracks should not run parallel to digital

tracks.

(g)

A "Ground Plane" connected to V

in

eliminating external pick-up on the channel input and

output pins.

(h)

Do not run high-level output tracks close to low-

level input tracks.

(i) Input signal amplitudes should be applied with due

regard to Figure 3.

(a)

A noisy or badly regulated power supply can

cause instability and/or variance of selected gains.

(b)

Care should be taken on the design and layout of

the printed circuit board.

(c)

All external components (Figure 2) should be

kept close to the FX019 package.

(d)

Inputs and outputs should be screened wherever

possible.

(e)

Tracks should be kept short.

To avoid excess noise and instability in the final installation it is recommended that the following points be noted.

Notes

(1) Channel Amplifiers 1 to 4 are inverting amplifiers.

(2) Analogue input capacitors C

input signals, d.c. input signals do not require these components.

Component

Value

C

0.1µF

C

5

1.0µF

C

6

1.0µF

Tolerances: C = ± 20%

Fig.2 External Component Connections