LM1868 National Semiconductor, LM1868 Datasheet - Page 6

• Manufacturer Part Number: LM1868
• Description: Radio System
• Manufacturer: National Semiconductor

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IC External Components
Component
C1
C2
C4 C5
C6 C9
R5
C10
C11
C12
C13
C14
C15
R7
C16
C17
R8
Coil and Tuning Capacitor Specifications
C1
L1
L0 L2 360 H Q
L4
L5
L6
L7
CF2
AM ANT 140 pF max 5 0 pF min
AM OSC 82 pF max 5 0 pF min
Trimmers 5 pF
640 H Q
R
(At secondary)
SWG
diameter
SWG
diameter
L
SWG
diameter
10 7 MHz ceramic filter
MURATA SFE 10 7 mA or
equivalent
P
e
e
0 44 H N
3k5
20 N
20 N
20 N
e
e
e
u
U l
100 pF
0 1 F
0 01 F
0 005 F
1k
10 F
0 1 F
10 F
0 1 F
50 F
0 1 F
3k
0 001 F
100 F
16k
Typical
e
5 mm
5 mm
5 mm
Value
F
TL H 7909–9
e
e
e
200
e
80
e
3 T inner
3 T inner
2
796 kHz
4
F
T inner
e
T Qu
796 kHz
Removes tuner LO from IF input
Antenna coupling capacitor
FM IF decoupling capacitors
AM smoothing FM de-emphasis
network de-emphasis pole is
given by
f1 j
Regulator decoupling capacitor
Regulator decoupling capacitor
AC coupling to volume control
Power supply decoupling
Power supply decoupling
Audio amplifier input coupling
Roll off signals from detector in
the AM band to prevent radiation
Power amplifier feedback
decoupling sets low frequency
supply rejection
AM detector bias resistor
e
70
2 (C6
FM 20 pF max 4 5 pF min
TOKO CY2-22124PT
AM antenna
1 mV meter induces
approximately 100 V
open circuit at the secondary
TOKO RWO-6A5105 or
equivalent
Toko America
1250 Feehanville Drive
Mount Prospect IL 60056
[phone]
Murata
2200 Lake Park Drive
Smyrna GA 30080
[phone]
Comments
a
(Application Circuit)
C9)
1
R4
R4 R6
a
R6
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Component
R9
C19
C7
C8
C20
R10
C21
R1
R2
R3
R4
R6
C18
R11 R12
D1
T1
T2
CF1
T3
TL H 7909– 10
TL H 7909– 11
TL H 7909– 12
TL H 7909– 13
240k
1 F
10 F
0 1 F
0 1 F
5
250 F
6k2
12k
5k6
10k
50k
0 02 F
150
1N4148
Typical
Value
Set AGC time constant
IF coupling
IF coupling
High frequency load for audio
amplifier required to stabilize
audio amplifier
Output coupling capacitor
Sets Q of quadrature coil
determining FM THD and
recovered audio
IF amplifier bias R
Sets gain of AM IF and Q of AM
IF output tank
Detector load resistor
Volume control
Power supply decoupling
Terminates the ceramic filter
biases FM IF input stage
Optional Quickens the AGC
response during turn on
Q
resonate w 82 pF
TOKO KAC-K2318 or equivalent
Q
resonate w 180 pF
TOKO 159GC-A3785 or
equivalent
TOKO CFU-090D or equivalent
BW
Apollo Electronics NS-107C
or equivalent
u l
u l
l
Comments
70
14
4 8 kHz
10 7 MHz L to
455 kHz L to
455 kHz
10 7 MHz
455 kHz