LA1837_09 Datasheet, PDF (4/9 Pages) Sanyo Semicon Device – For Home Stereo IC with Electronic Tuning Support Single-Chip IC

Test Circuit
AM-IN
(1MHz)
OSC
BUFF
(1.45MHz)
T1
LA1837
0.047μF
AFC
0.047μF
REG
39mH
10kΩ
+
+
+
18kΩ ^0.01μF
10μF
+
L.P.F
L.P.F L-OUT R-OUT
+
+
30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
LA1837
1
FM IN
(10.7MHz) 0.047μF
300Ω
2
3
450kHz
T2
4
5
+
6
7
8
SD ST
9 10
AM-ST
+
100μF _T3
11 12
FM _AM
VSM _VSM
13
+
14 15
FM ^STEREO
+
++
VDD
VCC
9.0V
Top view
Pin Functions
Pin No.
1
Pin function
FM IF input
Pin voltage (V)
Vreg
Pin description
Input impedance ri = 330Ω
2
AM mixer output
VCC
Connect the mixer coil between this pin and VCC.
Equivalent circuit
1
3
2
3
FM IF input bypass
4
AM IF input
Vreg
Vreg
Also functions as the MPX regulator filter.
Input impedance ri = 2kΩ
5
GND
6
TU-LED
7
ST-LED
AM-IF output
8
VCC
9
FM detector
0V
VCC
VCC
VCC
VCC
Active low
Open collector output
AM stereo IF output (pin 7)
The current input must not exceed 150μA.
Recommended detector coil : 600BEAS-9715Z
(The Toko Electric Corporation)
10
AM narrow band CF
connection
1.3V
Recommended narrow band CF: BFU450 C4N
(Murata Mfg. Co., Ltd.)
If the narrow band SD is not used, bypass this circuit
with a 50Ω resistor and a 0.047μF capacitor
connected in series.
See pin 1.
4
6
7
9
10
Continued on next page.
No.5688-4/9