Application Information
V
DD
C
1
XTAL/CLOCK
XTAL/CLOCK
For use with a Clock Pulse input
X
1
- Remove Xtal (X
1
)
- Connect Pin 1 to V
DD
XTAL
- Remove link (Pins 3/4)
OUT
- Input clock pulses to CLOCK IN
CLOCK
See Figure 4
1
2
3
4
5
6
7
24
23
V
DD
SYSTEM SELECT
V
SS
22
SERIAL DATA
IN
CLOCK IN
OUTPUT ENABLE
21
20
19
SERIAL CLOCK
CHIP SELECT
Ch2 OUTPUT
Ch1 OUTPUT
V
BIAS
Ch1 AMP OUT
FX641D2
PRESET LEVEL
18
17
16
15
14
13
R
6
OUTPUT SELECT
8
R
3
R
7
Ch2 AMP OUT
Ch2 AMP IN (-)
C
3
C
4
Ch1 AMP IN (-)
9
10
C
5
R
2
R
1
R
5
C
6
Ch1 AMP IN (+)
R
4
C
2
R
8
V
SS
11
12
Ch2 AMP IN (+)
V
SS
Component
R
1
R
2
R
3
R
4
R
5
R
6
R
7
R
8
Value
68kΩ
68kΩ
750kΩ
750kΩ
68kΩ
68kΩ
750kΩ
750kΩ
Tolerance
± 1%
±1%
±1%
±1%
± 1%
± 1%
±1%
±1%
C
1
C
2
C
3
C
4
C
5
C
6
X
1
1.0µF
1.0µF
270pF
270pF
270pF
270pF
3.579545MHz
±20%
±20%
±5%
±5%
±5%
±5%
Fig.2 Recommended External Components
Fixed Sensitivity Setting
Note that when calculating/selecting gain components, R
3
, R
4
, R
7
and R
8
should always be greater than or equal to
100kΩ.
Differential Input
Common Mode Input
INPUT AMP
INPUT AMP
Ring (b)
FX641 (part)
V
BIAS
FX641 (part)
V
BIAS
V
SS
V
SS
Fig.3 Example Input Configurations
+
-
+
-
Tip (a)
CMLMICRO [ CML MICROCIRCUITS ]
