fx009a Consumer Microcircuits Limited, fx009a Datasheet - Page 3

• Manufacturer Part Number: fx009a
• Description: Low-noise Digitally Controlled Amplifier Array
• Manufacturer: Consumer Microcircuits Limited

Application Notes
Application Recommendations
Fig.2 External Component Connections
(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)
kept close to the FX009A package.
(d) Inputs and outputs should be screened wherever
possible.
(e) Tracks should be kept short.
Fig.3 SINAD vs Input Level – Typical Values
Notes
To avoid excess noise and instability in the final installation it is recommended that the following points be noted.
(1) Channel Amplifiers 1 to 8 are inverting amplifiers.
(2) Analogue input capacitors C
input signals, d.c. input signals do not require these
components.
All external components (Figure 2) should be
SINAD (dB)
60
50
40
30
LOAD/LATCH
LOAD/LATCH
CHANNEL 1 INPUT
CHANNEL 2 INPUT
CHANNEL 3 INPUT
CHANNEL 4 INPUT
CHANNEL 5 INPUT
CHANNEL 6 INPUT
CHANNEL 7 INPUT
CHANNEL 8 INPUT
SERIAL CLOCK INPUT
-40
10.0
C
C
C
C
V
2
4
6
8
SS
25.0
-30
1
C
C
C
C
to C
1
3
5
7
C
10
8
are only required for a.c.
V
C
BIAS
9
Input Frequency = 1.0kHz
Input Level 0dB ref: = 775mVrms
Ch1 to Ch8 Gain Set to 0dB
75.0
-20
1
2
3
4
5
6
7
8
9
10
11
12
110.0
J - LG - LS
-17
FX009A
V
V
SS
DD
3
(f)
tracks.
(g)
eliminating external pick-up on the channel input and
output pins.
(h)
level input tracks.
(i) Input signal amplitudes should be applied with due
regard to Figure 3.
24
23
22
21
20
19
18
17
16
15
14
13
250.0
Tolerances: C =
Analogue tracks should not run parallel to digital
A "Ground Plane" connected to V
Do not run high-level output tracks close to low-
-10
Component
X
C
1
V
V
C
C
to C
DD
SS
10
9
8
SERIAL CONTROL DATA INPUT
CHANNEL 5 OUTPUT
CHANNEL 1 OUTPUT
CHANNEL 2 OUTPUT
CHANNEL 3 OUTPUT
CHANNEL 4 OUTPUT
CHANNEL 6 OUTPUT
CHANNEL 7 OUTPUT
CHANNEL 8 OUTPUT
20%
775.0
0
1000.0
INPUT LEVEL
Unit Value
1730.0
7
0.1
1.0
1.0
mVrms
SS
will assist in
dB