an7259s Panasonic Corporation of North America, an7259s Datasheet - Page 4

• Manufacturer Part Number: an7259s
• Description: Fm-if Amplifier Circuit For Car Radio
• Manufacturer: Panasonic Corporation of North America

AN7259S
• Control Signal Output Block
whose dynamic range is about 60dB wider for change of the input. This
control voltage is adjustable by the resistor R
at R
to be output from Pin2. This output from Pin3 requires insertion of a
capacitor (C
(right sketch) to be used for channel selection is obtainable on Pin4. The
band width of this search output is adjustable. (Refer to Detection Block.)
value varies with the input signal level.
• Soft Mute
output impedance is obtainable on this pin.
mode.
the soft mute response varies with the time constant of this voltage output.
The r
and with increase of the C
improved, but the speed of response accordingly becomes lower. The r
the other hand, is related to the soft mute OFF time. Each value specified in
the right sketch denotes a recommended value.
The polarity of the output voltage from Pin3 is reverse to that of the voltage
Application Circuit
Pin6 is the soft mute adjusting pin to adjust the attenuation at the non-input
Pin7 is the AF output pin, and the emitter follower output of 300
Pin Descriptions
The AN7259S has linear level meter output (control voltage on Pin2)
The search stop sensitivity is externally adjustable because the L level
Soft mute here denotes muting by the level signal output from Pin3, and
4
= 0.8k ~ 10k is more than 30dB in conversion of the input.
2
and C
FROM
F.E.
5
12
= 4.7 F) since it is used for soft muting. The search output
are related to the weak input S/N and the soft mute ON time,
10kB
20
1
12
value, the weak input S/N is proportionately
V
OUT
19
CONT.
2
330
+
18
3
4
of Pin1. The adjustable range
17
4
IF COUNTER
OUT
AN7259S
16
5
SEARCH
200k
100k
15
6
SSC
+
REF
14
7
1
, on
7.5k
in
200k
13
8
10kB
~ 20kB
2k
Control voltage
r
+
1
1000pF
R
+
4
1
12
3
0.22 F
9
0.022 F
AF OUT
200
4.7 F
r
C
Input
2
820
30kB
12
15pF
36k
200
2
30dB
To V
11
10
C
4
5
Increase of R
4.7
CC
F
Control voltage output
200
ICs for FM/AM Tuner
3
+
1.8
k
C
1.2k
5
R
Soft mute
adj.
6
5
4
V
4
Search output
CC
C
10k
0.22
7
6
F
0.022 F
Frequency
VR
Search output
R
20k
V
GND
6
CC
8
R
C
13
V
13
REF
AF
OUT