LA1784 [SANYO]
Single-Chip Tuner IC for Car Radios; 单芯片调谐器IC，适用于车载收音机
| 型号： | LA1784 |
| 厂家： | 
SANYO SEMICON DEVICE |
| 描述： | Single-Chip Tuner IC for Car Radios |
| 文件： | 总50页 (文件大小：563K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Ordering number : ENN6039
Monolithic Linear IC
LA1784M
Single-Chip Tuner IC for Car Radios
— Excellent FM signal meter linearity
Overview
— Modified N.C. circuit for improved noise rejection
• Double conversion AM tuner (up conversion)
Reduces the number of external components required as
compared to earlier double conversion tuners, in
particular, no crystal is required (when used in
conjunction with the LC72144).
• Sample-to-sample variation reduction circuit built into
the FM IF circuit.
(Fixed resistors are used for the SD, keyed AGC, mute
on adjustment, ATT, SNC, and HCC functions.)
• The LA1784 inherits the block arrangement of the
LA1780M and supports pin-compatible designs.
The LA1784M integrates all six blocks required in a car
radio tuner on a single chip.
Functions
• FM front end
• FM IF
• Noise canceller
• Multiplex
• AM up-conversion
• FM/AM switch
• MRC
Features
• Improved noise reduction methods
Package Dimensions
Unit:mm
— The FM front end provides excellent 3-signal
characteristics equivalent to those of the LA1193M.
— Superlative listenability due to improved medium and
weak field noise canceller characteristics.
— Improved separation characteristics
3159-QIP64E
[LA1784M]
17.2
1.6
1.0
14.0
0.35
1.0
48
0.8
0.15
33
— Anti-birdie filter
— Improved AM and FM thermal characteristics
32
49
3
Mounted on a 40 × 80 × 1.3 mm
17
glass epoxy printed circuit board
64
Independent IC
1
16
0.1
2.7
15.6
0.8
SANYO: QIP64E
Ambient temperature, Ta — °C
Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft’s
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.
SANYO Electric Co.,Ltd. Semiconductor Company
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
61501TN (OT) No. 6039-1/50
LA1784M
Specifications
Maximum Ratings at Ta = 25°C
Parameter
Symbol
Conditions
Ratings
Unit
V
V
CC1 max
CC2 max
Pins 6, 40, and 61
9
12
Maximum supply voltage
V
Pins 7, 45, 54, 59, and 60
V
Allowable power dissipation
Operating temperature
Storage temperature
Pd max
Topr
Ta ≤ 55°C
950
mW
°C
°C
–40 to +85
Tstg
–40 to +150
Operating Conditions at Ta = 25°C
Parameter
Symbol
VCC
CCST IND Pin 26
CC op
Conditions
Ratings
Unit
V
Pins 6, 7, 40, 45, 54, 59, 60, and 61
8
5
Recommended supply voltage
Operating supply voltage range
V
V
V
7.5 to 9.0
V
Operating Characteristics at Ta = 25°C, V = 8.0V, in the specified test cricuit for the FM IF input
CC
Ratings
unit
Parameter
Symbol
Conditions
min
typ
max
[FM Characteristics] At the FM IF input
Current drain
I
CCO-FM
No input, I40 + I45 + I54 + I59 + I60 + I61
60
205
190
–1
94
310
295
0
110
415
380
+1
mA
mVrms
mVrms
dB
Demodulation output
Pin 31 demodulation output
Channel balance
VO-FM
10.7 MHz, 100dBµ, 1 kHz, 100%mod, The pin 15 output
10.7 MHz, 100dBµ, 1 kHz, 100%mod, The pin 31 output
The ratio between pins 15 and 16 at 10.7 MHz, 100 dBµ, 1 kHz
VO-FM31
CB
Total harmonic distortion
Signal-to-noise ratio: IF
AM suppression ratio: IF
THD-FM mono 10.7 MHz, 100 dBµ, 1 kHz, 100% mod, pin 15
0.3
82
1
%
S/N-FM IF
AMR IF
10.7 MHz, 100 dBµ, 1 kHz, 100% mod, pin 15
75
55
dB
10.7 MHz, 100 dBµ, 1 kHz, fm = 1 kHz, 30% AM, pin 15
68
dB
10.7 MHz, 100 dBµ, 1 kHz. The pin 15
attenuation when V33 goes from 0 to 2 V
Att-1
Att-2
5
10
20
33
40
15
25
38
dB
dB
dB
dB
10.7 MHz, 100 dBµ, 1 kHz. The pin 15
attenuation when V33 goes from 0 to 2 V*1
Muting attenuation
Separation
15
28
30
10.7 MHz, 100 dBµ, 1 kHz. The pin 15
attenuation when V33 goes from 0 to 2 V*2
Att-3
10.7 MHz, 100 dBµ, L+R = 90%, pilot = 10%. The pin 15 output
ratio
Separation
Stereo on level
ST-ON
ST-OFF
The pilot modulation such that V26 < 0.5 V
2.1
1.2
4.1
3.1
0.3
6.5
1.2
%
%
%
Stereo off level
The pilot modulation such that V26 > 3.5 V
Main total harmonic distortion
THD-Main L
10.7 MHz, 100 dBµ, L+R = 90%, pilot = 10%. The pin 15 signal
10.7 MHz, 100 dBµ, pilot = 10%.
The pin 15 signal/the pilot level leakage. DIN audio
Pilot cancellation
PCAN
AttSNC
20
1
30
5
dB
dB
dB
dB
10.7 MHz, 100 dBµ, L-R = 90%, pilot = 10%.
V28 = 3 V → 0.6 V, pin 15
SNC output attenuation
9
10.7 MHz, 100 dBµ, 10 kHz, L+R = 90%, pilot = 10%.
V29 = 3 V → 0.6 V, pin 15
AttHCC-1
AttHCC-2
0.5
6
4.5
10
8.5
14
HCC output attenuation
10.7 MHz, 100 dBµ, 10 kHz, L+R = 90%,
pilot = 10%. V29 = 3 V → 0.1 V, pin 15
100 dBµ, 10.7 MHz, 30% modulation. The IF input such
that the input reference output goes down by 3 dB
Input limiting voltage
Muting sensitivity
Vi-lim
Vi-mute
33
27
54
40
35
62
47
43
70
dBµ
dBµ
dBµ
The IF input level (unmodulated) when V33 = 2 V
The IF input level (unmodulated) (over 100 mV rms)
such that the IF counter buffer output goes on
SD-sen1 FM
SD sensitivity
SD-sen2 FM
VIFBUFF-FM
54
130
0.0
62
200
0.1
70
270
0.3
dBµ
IF counter buffer output
10.7 MHz, 100 dBµ, unmodulated. The pin 23 output
No input. The pin 24 DC output, unmodulated
50 dBµ. The pin 24 DC output, unmodulated
70 dBµ. The pin 24 DC output, unmodulated
100 dBµ. The pin 24 DC output, unmodulated
100 dBµ. The bandwidth when V33 = 2 V, unmodulated
100 dBµ, 0 dBµ. The pin 33 DC output, unmodulated
mVrms
V
SM FM-1
V
V
VSM FM-2
0.4
1.0
1.5
Signal meter output
V
SM FM-3
SM FM-4
2.0
2.7
3.5
V
V
4.7
5.5
6.2
V
Muting bandwidth
Mute drive output
BW-mute
VMUTE-100
150
0.00
220
0.03
290
0.20
kHz
V
Continued on next page.
No. 6039-2/50
LA1784M
Continued from preceding page.
Ratings
typ
unit
Parameter
[FM FE Mixer Input
N-AGC on input
Symbol
Conditions
min
max
83 MHz, unmodulated.
VN-AGC
VWAGC
81
88
95
dBµ
dBµ
The input such that the pin 2 voltage is 2.0 V or below
83 MHz, unmodulated. The input such that the pin 2
voltage is 2.0 V or below. (When the keyed AGC is set to 4.0 V.)
W-AGC on input
104
110
116
Conversion gain
A.V
83 MHz, 80 dBµ, unmodulated. The FE CF output
No input
19
85
30
48
mVrms
mVrms
Oscillator buffer output
[NC Block] NC input (pin 30)
Gate time
VOSCBUFFFM
110
165
τGATE1
f = 1 kHz, for a 1-µs, 100-mV p-o pulse
55
40
µs
The level of a 1 = kHz, 1-µs pulse input that starts
noise canceller operation. Measured at pin 30.
Noise sensitivity
SN
mVp-o
The pulse rejection effect provided by the noise canceller.
For a repeated 1-µs wide pulse, frequency = 10 kHz,
150 mV p-o. The ratio of the FM mode pin 15 output
referenced to the AM mode pin 15 output (effective value)
NC effect
SN-NC
5
[Multipath Rejection Circuit] MRC input (pin 27)
MRC output
VMRC
V24 = 5 V
2.2
10
2.3
15
2.4
20
V
The pin 32 input level at f = 70 kHz such that
pin 24 goes to 5 V and pin 27 goes to 2 V
MRC operating level
MRC-ON
mVrms
[AM Characteristics] AM ANT input
Practical sensitivity
S/N-30
VO-AM
1 MHz, 30 dBµ, fm = 1 kHz, 30% modulation, pin 15
1 MHz, 74 dBµ, fm = 1 kHz, 30% modulation, pin 15
1 MHz, 74 dBµ, fm = 1 kHz, 30% modulation, pin 31
20
dB
Detector output
130
110
195
175
270
230
mVrms
mVms
Pin 31 detector output
VO-AM31
1 MHz, 74 dBµ, referenced to the output, the input amplitude
such that the output falls by 10 dB. Pin 15
AGC F.O.M.
VAGC-FOM
59
47
64
69
dB
Signal-to-noise ratio
S/N-AM
1 MHz, 74 dBµ, fm = 1 kHz, 30% modulation
1 MHz, 74 dBµ, fm = 1 kHz, 80% modulation
No input
52
0.3
0.2
4.4
230
98
dB
%
Total harmonic distortion
THD-AM
1
V
V
SM AM-1
SM AM-2
0.0
3.5
185
92
0.5
6.1
V
Signal meter output
1 MHz, 130 dBµ, unmodulated
V
Oscillator buffer output
Wide band AGC sensitivity
VOSCBUFF AM1 No input, the pin 15 output
mVrms
dBµ
dBµ
dBµ
dBµ
mVrms
W-AGCsen1
W-AGCsen2
SD-sen1 AM
SD-sen2 AM
VIFBUFF-AM
1.4 MHz, the input when V46 = 0.7 V
104
95
1.4 MHz, the input when V46 = 0.7 V (seek mode)
83
89
1 MHz, the ANT input level such that the IF counter output turns on.
1 MHz, the ANT input level such that the SD pin goes to the on state.
1 MHz, 74 dBµ, unmodulated. The pin 23 output
24
30
36
SD sensitivity
24
30
36
IF buffer output
200
290
Note: These measurements must be made using the either the IC-51-0644-824 or KS8277 IC socket (manufactured by Yamaichi Electronics).
* 1. When the resistor between pin 58 and ground is 200 kΩ.
* 2. When the resistor between pin 58 and ground is 30 kΩ.
No. 6039-3/50
LA1784M
Function List
FM Front End (Equivalent to the Sanyo LA1193)
• Double input type double balanced mixer
• Pin diode drive AGC output
• MOSFET second gate drive AGC output
• Keyed AGC adjustment pin
Multiplex Functions
• Adjustment-free VCO circuit
• Level follower type pilot canceller circuit
• HCC (high cut control)
• Automatic stereo/mono switching
• VCO oscillation stop function (AM mode)
• Forced monaural
• Differential IF amplifier
• Wide band AGC sensitivity setting pin, and narrow
band AGC sensitivity setting pin
• Local oscillator
• SNC (stereo noise controller)
• Stereo display pin
• Anti-birdie filter
FM IF
• IF limiter amplifier
AM
• S-meter output (also used for AM) 6-stage pickup
• Multipath detection pin (shared FM signal meter)
• Quadrature detection
• Double balanced mixer (1st, 2nd)
• IF amplifier
• Detection
• AF preamplifier
• RF AGC (narrow/wide)
• AGC output
• Pin diode drive pin
• Band muting
• IF AGC
• Weak input muting
• Signal meter output (also used for FM)
• Local oscillator circuits (first and second)
• Local oscillator buffer output
• IF counter buffer output (also used by the FM IF)
• SD (IF counter buffer on level) adjustment pin
• SD output (active high) (also used for AM)
• Wide AGC
• Soft muting adjustment pin
• Muting attenuation adjustment pin
• IF counter buffer output (also used for AM)
• SD (IF counter buffer on level) adjustment pin
• SD output (active high) (also used for AM)
Noise Canceller
• Detection output frequency characteristics
adjustment pin (low cut, high deemphasis)
• AM stereo buffer
• High-pass filter (first order)
• Delay circuit based low-pass filter (fourth order)
• Noise AGC
• Pilot signal compensation circuit
• Noise sensitivity setting pin
• Function for disabling the noise canceller in AM
mode
MRC (multipath noise rejection circuit)
AM/FM switching output (linked to the FM V
)
CC
No. 6039-4/50
LA1784M
Operating Characteristics and Symbols Used in the Test Circuit Diagrams
Switches (SW)
Switch on = 1, SW off = 0
There are two switches that use signal transfer.
— SW2: switches between the mixer input and the IF input.
— SW4: switches between noise canceler input and IF output + noise canceler input.
Types of SG used
PG1 (AC1) Used for noise canceler testing. A pulse generator and an AF oscillator are required.
AC2
AC3
AC4
AC5
Used for FM front end testing. Outputs an 83 MHz signal.
Used for FM IF, noise canceler, and MPX testing. Outputs a 10.7 MHz signal. Stereo modulation must be possible.
Used for AM testing. Outputs 1 MHz and 1.4 MHz signals.
Used with the MRC. Can also be used for AF and OSC.
Power supply
VCC
8 V
V
V
V
CC1
5 V
SD, stereo, seek/stop
Keyed AGC, Mute ATT
HCC, SNC, SASC (MRC)
CC2
CC3
0.1 V / 0.7 V / 2 V / 4 V
0.1 V / 0.6 V / 2 V
These levels
must be variable.
• Switches
Parameter
ON
FM
OFF
AM
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
SW9
AM/FM switching. The FE VCC is supplied to pin 62.
FM IF switching. Pin 51/FE output
For conversion gain testing
FE IF OUT (A)
AC3 (B)
Conversion gain measurement (A)
AC1 (A)
Other/purposes
Other/purposes
Other/purposes
Seek (IF buffer output)
OFF
For switching between noise canceler input and IF output + noise canceler.
High-speed SD
High-speed SD
STOP
SEEK/STOP (IF BUFF ON/OFF)
MUTE ATT 200 kΩ
MUTE 200 kΩ
MUTE ATT 30 kΩ
MUTE 30 kΩ
OFF
For pilot cancellation testing
When pilot cancellation is used
MUTE OFF
When pilot cancellation is not used
MUTE ON
SW10 Mute off (pin 33)
• Trimmers (variable resistors)
VR1
VR2
Separation adjustment
Pilot cancellation adjustment
Test Points
• DC voltages
VD1
VD2
VD3
VD4
VD5
VD6
VD7
FM RF AGC voltage
Pin 2
AM/FM SD, AM Tweet, FM stereo indicator Pin 26
AM/FM S-meter
Pin 24
Pin 27
Pin 33
Pin 46
Pin 8
MRC output
Mute drive output
AM antenna damping voltage
N.C. Gate time
• AC voltages
VA1
VA2
VA3
VA4
VA5
AM/FM OSC Buff
Pin 4
First IF output
Pin 53 → CF → pin 51 load level (10.7 MHz)
Pin 23 (10.7 MHz/450 kHz)
Pin 15 (AF)
IF counter buffer
MPX OUT Left ch
MPX OUT Right ch
Pin 16 (AF)
No. 6039-5/50
LA1784M
Pin Descriptions
Pin No.
Function
Description
Equivalent circuit
62 pin
V
CC
ANT
RF
AGC
1000 pF
An antenna damping current flows
when the RF AGC voltage (pin 2)
reaches VCC – VD.
300 Ω
1
Antenna damping drive
100 Ω
1
100 Ω
1000 pF
A11711
V
CC
FET
2ND GATE
12 kΩ
2
+
Used to control the FET
second gate.
2
RF AGC
DAMPING
DRIVER
ANT
N
W
AGC
DET
AGC
DET
V
CC
KEYED
AGC
A11712
3
F.E.GND
V
CC
Oscillator connection
4
The transistor and capacitors
required for the oscillator circuit.
4
OSC
25 pF
20 pF
2 kΩ
V
T
A11713
7
V
CC
AM first oscillator
This circuit can oscillator up to the
SW band.
7
AM OSC
An ALC circuit is included.
A
L C
A11714
Continued on next page.
No. 6039-6/50
LA1784M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
3 kΩ
3 kΩ
15 kΩ
After setting up the medium field
(about 50 dBµ) sensitivity with the
noise sensitivity setting pin (pin 8),
set the weak field (about 20 to
30 dBµ) sensitivity with the AGC
adjustment pin (pin 9)
200 Ω
8
9
Noise AGC sensitivity
AGC adjustment
8
9
3 kΩ
0.01 µF
+
0.47 µF
1 MΩ
A11715
0.01 µF
6800 pF
3.9 kΩ
13
12
11
V
CC
11
12
Recording circuit used during
noise canceller operation.
Memory circuit connection
Differential
amp
Gate
circuit
LPF
A11716
V
CC
30 kΩ
PLL
13
Pilot input
Pin 13 is the PLL circuit input pin.
N.C
12
13
0.01 µF
A11717
Ground for the N.C., MPX, and
MRC circuits.
14
N.C, MPX, MRC, GND
Continued on next page.
No. 6039-7/50
LA1784M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
V
CC
Deemphasis
50 µs: 0.015 µF
75 µs: 0.022 µF
15
16
MPX output (left)
MPX output (right)
3.3 kΩ
3.3 kΩ
15
16
0.015 µF
0.015 µF
A11718
V
CC
20 kΩ
10 kΩ
Adjustment is required since the
pilot signal level varies with the
sample-to-sample variations in
the IF output level and other
parameters.
6.7 kΩ
17
Pilot canceller signal output
17
18
0.01 µF
100 kΩ
A11719
V
CC
Pin 18 is the output pin for the
pilot canceller signal.
18
Pilot canceller signal output
1.5 kΩ
17
18
0.01 µF
100 kΩ
A11720
Continued on next page.
No. 6039-8/50
LA1784M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
DECODER
Composite
signal
5 kΩ
Use a trimmer to adjust the
subdecoder input level.
(The output level is not modified in
mono and main modes.)
Separation
adjustment pin
19
19
30 kΩ
0.047 µF
A11721
CSB
912
JF108
20
V
REF
20
VCO
The oscillator frequency is 912 Hz.
KBR-912F108
10 pF
(Kyocera Corporation)
CSB-912JF108
(Murata Mfg. Co., Ltd.)
A11722
V
REF
15 kΩ
15 kΩ
21
22
PHASE COMP.
PHASE COMP.
+
19 kΩ
21
22
A11723
Continued on next page.
No. 6039-9/50
LA1784M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
+
–
4.9 V
AM MUTE
50 kΩ
+
–
1.3 V
IF counter
buffer
V
CC
This pin functions both as the IF
counter buffer (AC output) and as
the seek/stop switch pin.
The voltage V23 switches
between the following three
modes.
10 kΩ
+
–
150 Ω
SW
50F
IF counter buffer seek/stop
switching
During FM reception:
5 V: Seek mode
23
2.5 V: Forced SD mode
0 V: Reception mode
AM reception
SD circuit
23
51 kΩ
(two modes: 0 and 5 V)
5 V: Seek mode
0 V: Reception mode
STOP
IF
BUFF.
Forced
SEEK
SD: 2.5 V
5 V
A11724
V
CC
FM
S-meter
32
24
32
AM/FM signal meter
Fixed-current drive signal meter
output
10 kΩ
AM
S-meter
In AM mode, pin 32 outputs a
1-mA current. Thus the HCC
circuit is turned off.
24
Dedicated FM signal meter
10 kΩ
AM/FM
SW
Outputs a 1-mA
current during AM
reception
AM/FM
SW
MRC
A11725
The voltage V23 switches
between three modes as follows.
FM reception:
5 V: The SD pin operates linked
to the IF counter buffer.
AM/FM
SD
Stereo
indicator
2.5 V: Forced SD mode: operates
as the SD pin.
Seek/stop
switching
26
Stereo indicator for the SD pin
0.7 V: Reception mode: stereo
indicator
26
AM reception: (two modes: 0 and 5 V)
5 V: Operates as the seek SD pin.
0 V: Reception mode. Not used.
100 kΩ
V
DD
A11726
Continued on next page.
No. 6039-10/50
LA1784M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
V
CC
V
CC
2 µA
C2
27
The MRC detector time constant
is determined by a 100 Ω resistor
and C2 when discharging and by
the 2-µA current and C2 when
charging.
100 Ω
27
MRC control voltage time
constant
Pin 28
A11727
V
REF
The sub-output is controlled by a
0 to 1-V input.
28
SNC control input
28
A11728
V
REF
The high band frequency output is
controlled by a 0 to 1-V input.
It can also be controlled by the
MRC output.
29
HCC control input
Use a resistor of at least 100 kΩ
when controlling with the pin 32
FM S-meter signal.
32
29
+
1 µF
A11729
Continued on next page.
No. 6039-11/50
LA1784M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
V
CC
FM
detector
output
31
Pin 30 is the noise canceller input.
The input impedance is 50 kΩ.
10 kΩ
30
31
Noise canceller input
AM/FM detector output
V
CC
Pin 31 is the AM and FM detector
output
In FM mode, this is a low-
impedance output.
In AM mode, the output
impedance is 10 kΩ.
To improve the low band
separation, use a coupling
capacitor of over 10 µF.
1 µF
AM
detector
+
30
Noise
canceller
50 kΩ
4.2 V
A11730
V
CC
32
FM S-meter output block
MRC AC input block
Adjust the external 1-kΩ resistor
to attenuate the MRC AC input
and control the circuit.
10 kΩ
+
1 µF
32
IF S-meter output and MRC
DC input
1 kΩ
MRC input
A11731
C1
+
0.1 µF
•The muting time constant is
determined by an external RC
circuit as described below.
Attack time: TA = 10 kΩ × C1
Release time: TR = 50 kΩ × C1
33
V
CC
50 kΩ
10 kΩ
MUTE
AMP.
•Noise convergence adjustment
The noise convergence can be
adjusted when there is no input
signal by inserting a resistor
between pin 33 and ground.
SEEK
OFF
33
Mute drive output
SOFT HOLE
MUTE DET
Band
muting
50 kΩ
•Muting off function
Ground pin 33 through a 4-kΩ
resistor.
SD circuit
A11732
Continued on next page.
No. 6039-12/50
LA1784M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
0.1 µF
V
R1
REF
V
CC
C
R2
36
37
35
34
V
CC
•The resistor R1 determines the
width of the band muting function.
Increasing the value of R1
narrows the band.
Reducing the value of R1 widens
the band.
Quadrature
detector
34
35
36
37
AGC
QD output
QD input
VREF
•Null voltage
When tuned, the voltage between
pins 34 and 37, V
The band muting function turns
HOLE
DET
, will be 0 V.
34 – 37
3 pF
on when |V34 – 37| ≥ 0.7 V.
V
37 = 4.9 V
1 kΩ
IF limitter amplifier
Band
muting
A11733
R
SD ADJ
38
A 130-µA current flows from pin
38 and, in conjunction with the
external resistance R, determines
the comparison voltage.
38
FM SD ADJ
130 µA
+
–
SD
Comparator
24
24
S-meter
A11734
S-meter
6.4 kΩ
3.6 kΩ
The keyed AGC operates when
the voltage created by dividing the
pin 24 S-meter output voltage by
the 6.4 and 3.6 kΩ resistors
becomes lower than the voltage
determined by the resistor
Comparator
KEYED
AGC
+
–
39
39
Keyed AGC
AM stereo buffer
90 µA
1.3 V
between pin 39 and ground.
V
CC
This pin also is used as the AM
stereo IF buffer pin.
AM IF out
50 pF
150 Ω
A11735
Continued on next page.
No. 6039-13/50
LA1784M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
V
CC
20 kΩ
+
20 kΩ
The HCC frequency characteristics
are determined by the external
capacitor connected at this pin.
41
HCC capacitor
41
2200 pF
A11736
This pin is used to change the
frequency characteristics of the
unneeded audio band under
100 Hz in AM mode to produce
a clear audio signal.
V
CC
C
42
Note: The LC capacitor must be
connected between this pin
and VCC (pin 40).
V
CC
DET
42
AM L.C. pin
This is because the detector
circuit operates referenced
50 kΩ
50 kΩ
1 kΩ
+
–
to VCC
.
1 kΩ
The cutoff frequency fC is
determined by the following
formula.
A11737
fC = 1/2π × 50 k × C
V
CC
19 kHz 0°
BIAS
30 kΩ
Inserting a 1-MΩ resistor between
pin 43 and VCC will force the IC
to mono mode.
30 kΩ
30 kΩ
43
Pilot detector
+
43
1 µF
+
A11738
Continued on next page.
No. 6039-14/50
LA1784M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
V
CC
+
C
0.022 µF
2.2 µF
240 kΩ
42
44
V
CC
G1; Used for time constant
switching during seeks.
• Reception
τ = 2.2 µF × 300 kΩ
• Seek
DET
50 kΩ
50 kΩ
44
IF AGC
τ = 2.2 µF × 10 Ω
The external capacitors are
connected to VCC
This is because the IF amplifier
operates referenced to VCC
.
IF
AGC
G1
.
SEEK
ON
10 Ω
A11739
Pin 40 V
CC
45
Pin 40 V
CC
45
IF output
The IF amplifier load
DET
A11740
V
CC
50 pF
46
100 Ω
AM antenna damping
drive output
Wide band AGC input
I46 = 6 mA (maximum)
This is the antenna damping
current.
46
20 kΩ
V
CC
W.AGC AMP.
ANT DAMPING
DRIVER
A11741
Continued on next page.
No. 6039-15/50
LA1784M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
30 kΩ
R
47
V
CC
Modify the value of the external
resistor to adjust the muting on
level.
140 µA
FM muting on level
adjustment
47
–
+
Inverter
Pin 24
MUTE
A11742
V
CC
5.6 V
10 kΩ
RF AGC rectification capacitor
The low frequency distortion is
determined as follows:
+
–
Antenna
damping
48
+
Increasing C48 and C57 improves
the distortion but makes the
response slower.
3.3 µF
48
57
RF AGC bypass
RF AGC
Reducing C48 and C57
aggravates the distortion but
makes the response faster.
For AGC use
57
+
47 µF
A11743
2.6 V
10 kΩ
10 kΩ
Due to the high gain of the limiter
amplifer, care must be taken when
choosing the grounding point for
the limiter amplifer input capacitor
to prevent oscillation.
50
50
51
IF bypass
FM IF input
330 Ω
51
0.022 µF
IF in
A11744
2 kΩ
100 Ω
52
IF input
The input impedance is 2 kΩ.
52
A11745
Continued on next page.
No. 6039-16/50
LA1784M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
V
CC
IF OUT 53
• Input and output pin or the first
IF amplifier
300 Ω
• Inverting amplifier
300 Ω
53
56
IF amplifier output
IF amplifier input
V56 = 2 V
Input impedance: RIN = 330 Ω
2.75 V
V53 = 5.3 V
Output impedance
ROUT = 330 Ω
IF IN 56
Pin 40 V
A11746
CC
Pin 40 V
CC
54
OSC
The mixer coil connected to the
pin 54 mixer output must be
wired to VCC (pin 40).
54
49
Mixer output: 130 µA
Mixer input
The pin 49 mixer input
impedance is 330 Ω
49
330 Ω
A11747
W-AGC
N-AGC
Pin 62
V
CC
Pins 55 and 58 include built-in
DC cut capacitors.
The AGC on level is determined
by the values of the capacitors
C1 and C2.
30 pF
55
58
W-AGC IN
AM SD ADJ
Pin 55 functions as the SD
sensitivity adjustment pin in
AM mode.
55
58
C1
50 pF
N-AGC IN
Muting attenuation
adjustment pin
The output current I55 is 50 µA,
and V55 varies depending on the
value of the external resistor.
The SD function operates by
comparing V55 with the S-meter
voltage.
MIX
IN
C2
50 µA
+
–
MIX
OUT
AM SD
Signal meter
A11748
Continued on next page.
No. 6039-17/50
LA1784M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
1ST.IF
O
S
C
59
60
Double balanced mixer
Pins 59 and 60 are the mixer
10.7-MHz output
V
CC
59
60
Mixer output
Mixer input
Pins 63 and 64 are the mixer
input.
This is an emitter insertion type
circuit, and the amount of
insertion is determined by the
capacitors C1 and C2.
30 Ω
V
CC
63
64
C1
63
64
5 pF
C2
Note:The lines for pins 63 and 64
must be kept separated from
the lines for pins 59 and 60.
RF AMP
5 pF
620 Ω
620 Ω
A11749
510 Ω
V
CC
SD
Pin 6 functions both as the FM
front end VCC and the AM/FM
switching circuit.
AM/FM
switching circuit
+
–
6
+
6
Front end VCC AM/FM
switching
FM.F.E
AGC
100 kΩ
V6 voltage
When 8 V → FM
OPEN → AM
Mode
3.3 V
8 V
3
GND
A11750
AM 1st
MIX
to RF
Amp.
62
10 kΩ
First mixer input
The input impedance is about
10 kΩ.
1st MIX
INPUT
62
2.1 V
A11751
10 kΩ
20 pF
33 pF
5.6 V
to 2nd
MIX
Crystal oscillator circuit
The Kinseki, Ltd. HC-49/U-S and
a CL of 20 pF must be used.
10
AM 2nd OSC
10
X tal
A11752
No. 6039-18/50
LA1784M
Block Diagram
V
CC
0.022µF
TO AM STEREO
GND
(IF OUT)
+
10kΩ
+
+
+
+
+
0.1µF
240kΩ
10kΩ
37 36
RFAGC
MUTE DRIVE
33
30Ω
0.022µF
0.022µF
1µF
48
47
46
45
44
43
42
41
40
39
38
35
34
1kΩ
620Ω
1MH
100µF
100kΩ
FM
ANT
D
OSC
BUFF
49
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
OSC
METER
50kΩ
AM LEVEL ADJ
AM HC
FC18
DET OUT
FM IF IN
100µH
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
MUTE
AMP
+
0.022µF
Q.DET
F imte
limiter
IF
220Ω
+
8200pF
amplifier
30MH
0.022µF
BUFF
NC-IN
HCC
100Ω
1µF
HOLE
DET
MUTE
DRIVE
AM IF IN
IF
AGC
AMVSM
AM SD
FMVSM
FM SD
DET
L.C.
510kΩ
ANTD
0.022µF
DC-C AFC
DET CLAMP
SNC
FM IF OUT
IF BUFF
1µF
MRC
10kΩ
AM SD ADJ
AM MIX OUT
+
MIX
SNC
HCC
IF
REG
AM/FM
SW
RF AGC
WB AGC
TWEET
FM WB AGCIN
FE IF IN
20kΩ
SEEK→AM/FM SD
STOP→FM ST IND.
GND
AM FM
VREF
AM/FM
5V
0.47µF
FF
19k<90
k
SEEK
SW
S-METER
VCO
STOP
PHASE
COMP
200kΩ
62pF
300Ω
SD/ST
IND
MAIN
W.B.AGC
RF AGC
HC
0.022µF
FF
VCO
MUTE ATT
5.6kΩ
19k<0
2kΩ
AMP
KEYED
AGC
INPUT
+
+
V
30Ω
CC
0.22µF
PILOT
DET
1µF
*
HPF
LPF
TRIG
*
CSB912JF108
or
MIX
AM/FM
FEV
CC
KBR912F108
P-CAN
NOISE
AMP
–
+
0.022µF
0.047µF 20kΩ
FF
38k<0
AMP
V
PICAN
INPUT
CC
SEP.ADJ
BUFF
8pF
30Ω
BUFF
AM
1ST
FF
AGC TRIG
GATE
SUB MAT
DEC RIX
1000pF
5pF
100kΩ
COUNTER
OSC
22pF 22pF
ANT
D
5pF
0.01µF
PI.CAN ADJ
1000pF
1
2
3
4
5
6
7
8
9
10
AM
OSC
11
12
13
14
15
MPX
OUT
16
+
18pF
6800pF 0.01µF
200kΩ
GND
0.1µF
30kΩ
10pF
+
5pF
100Ω
0.022µF
30kΩ
GND
300pF
10.26MHz
NC MPX GND
30kΩ
18pF
10µF
10µF
10µF
R
L
10µF
0.22µF
1µF
10kΩ
2.2kΩ
10kΩ
10µF
0.01µF
3SK583
+B
12V
100pF 100pF 100pF 100pF
0.22µF
18 17
22pF
+
20
19
16
15
14
13
12
11
V
PD
V
FM IN AM IN
5.6V
SS
DD
7.2MHz
LC7216M
CE
2
CI
3
CL
DO
5
FM/AM
10
+
1
4
6
7
8
9
9.1V
22pF
100pF
CE
CI
CL
DO
RDS
ADC MUTE SD/MONO
ST
R ON
LC867148
A11753
No. 6039-19/50
LA1784M
AC Characteristics Test Circuit
V
CC
8V
GND
V
CC
+
0.022µF
IF OUT
10kΩ
VA2
IF IN
SW3
50Ω
300Ω
4.3kΩ
B
+
+
VD5
MRC-IN
1µF
+
SW2 ( i )
MIX
+
+
AC3
SG3
A
0.1µF
240kΩ
10kΩ
37 36
RFAGC
MUTE DRIVE
33
V
2
CC
48
47
46
45
44
43
42
41
40
39
38
35
34
FM S-METER
ANT
D
49
OSC
BUFF
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
OSC
FM IF
IN
AM LEVEL ADJ
AC5
PG1
DET OUT
+
50
SW4 (T)
A
MUTE
AMP
Q.DET
8200pF AM HC
IF limiter
amplifier
B
NC-IN
51
52
53
54
55
56
57
58
59
60
61
62
63
64
30Ω
0.022µF
BUFF
NC-IN
HCC
(AC1)
HOLE
DET
MUTE
DRIVE
AM IF IN
IF
AGC
AMVSM
AM SD
FMVSM
FM SD
DET
L.C.
HCC
SNC
0.022µF
1MH
DC-C AFC
DET CIAMP
SNC
620Ω
V
3
CC
FM IF OUT
IF BUFF
1µF
100µH
VD4
AM SD ADJ
AM MIX OUT
+
MIX
FC18
RF AGC
W.B. AGC
MRC
VD2
SEEK→AM/FM SD
TWEET
100µH
50Ω 30Ω
15pF
FM WB AGCIN
FE IF IN
GND
STOP→AM ST BUFFER
+
FM ST IND.
65pF
AC2
SG2
AM/FM
S-METER
0.47µF
FF
19<90
k
50kΩ
PHASE
COMP
JIS
DUMMY
SNC
HCC
10pF
AM FM
VREF
510Ω
VA3
5V
HPF
LPF
W.B.AGC
RF AGC
ANTD
0.022µF
V
1
CC
FF
19<0
FM/AM IFBUFF.
VCO
MUTE ATT
5.6kΩ
1kΩ
0.022µF
KEYED
AGC
+
VCO
STOP
50kΩ
FF FM/AM
REG
+
300kΩ
0.22µF
SW
VD6
–
+
PILOT
DET
1µF
CSB912JF108
TRIG
SW5
SW6
MIX
AM/FM
V
FEV
CC
CC
BUFF
V
CC
BUFF
P-CAN
VD3
0.047µF 20kΩ
SW8
SW7
FF
38k<0
AM
1ST
OSC
VR1
SEP.ADJ
8V
V
2
CC
3pF
3pF
50Ω
25Ω
1000µF
MAIN
HC
SW9
0.022µF
FF
VA8
SUB MA
DEC TRIX
5pF
5pF
AGC TRIG
GATE
AC1
SG1
100kΩ
VR2
0.01µF
PI.CAN ADJ
ANT
D
1
2
3
4
5
6
7
8
9
10
AM
11
12
13
14
15
MPX
OUT
16
OSC
20pF
OSC
+
VD1
6800pF 0.01µF
100Ω
+
100Ω
0.022µF
8V
SW10
GND
3pF
20kΩ
0.022µF
10.26MHz
X TAL
0.022µF
V
V
CC
10µF
VA6
CC
10µF
VA7
SW1
8V
VT
VA1
VA9
A11754
No. 6039-20/50
LA1784M
Test Conditions
Switch states
Parameter
Symbol
SW1
SW2
b
SW3
SW4
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
a
a
a
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
b
SW5
—
SW6
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
SW7
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
—
SW8
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
SW9
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
SW10
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
ON
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
Current drain
ICCO-FM
ON
ON
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
Demodulation output
Pin 31 demodulation output
Channel balance
VO-FM
b
—
VO-FM31
CB
ON
b
—
ON
b
—
Total harmonic distortion (FM)
Signal-to-noise ratio: IF
AM suppression ratio: IF
THD-FMmono
S/N-FM IF
AMR IF
ON
b
—
ON
b
—
ON
b
—
Att-1
ON
b
—
Muting attenuation
Att-2
ON
b
—
Att-3
ON
b
—
Separation
Separation
ST-ON
ON
b
—
Stereo on level
ON
b
—
Stereo off level
ST-OFF
THD-Main L
PCAN
ON
b
—
Main total harmonic distortion
Pilot cancellation
ON
b
—
ON
b
—
OFF OFF/ON
SNC output attenuation
HCC output attenuation 1
HCC output attenuation 2
Input limiting voltage
Muting sensitivity
AttSNC
ON
b
—
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
—
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
—
AttHCC-1
AttHCC-2
Vi-lim
ON
b
—
ON
b
—
ON
b
—
Vi-mute
ON
b
—
SD sensitivity 1
SD-sen1 FM
SD-sen2 FM
VIFBUFF-FM
ON
b
OFF
ON
OFF
—
SD sensitivity 2
ON
b
IF counter buffer output
ON
b
VSM FM-1
ON
b
VSM FM-2
ON
b
—
Signal meter output (FM)
V
SM FM-3
SM FM-4
ON
b
—
V
ON
b
—
Muting bandwidth
Mute drive output
N-AGC on input
W-AGC on input
Conversion gain
Oscillator buffer output
Gate time 1
BW-mute
VMUTE-100
VNAGC
ON
b
—
ON
b
—
ON
a
—
VWAGC
ON
a
ON
—
—
A.V
ON
a
ON
—
—
VOSCBUFFFM
τGATE1
SN
ON
a
ON
—
—
ON
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
—
—
Noise sensitivity
NC effect
ON
—
—
SN-NC
ON/OFF
ON
—
—
MRC output
VMRC
—
—
MRC operating level
Practical sensitivity
Detection output
Pin 31 detection output
AGC F.O.M.
MRC-ON
S/N-30
ON
—
—
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
—
VO-AM
—
—
—
VO-AM31
VAGC-FOM
S/N-AM
THD-AM
VSM AM-1
—
—
—
—
—
—
Signal-to-noise ratio
Total harmonic distortion (AM)
—
—
—
—
—
—
—
—
—
Signal meter output (AM)
Oscillator buffer output
Wide band AGC sensitivity
VSM AM-2
—
—
—
VOSCBUFF AM-1
W-AGCsen 1
W-AGCsen 2
SD-sen1 AM
SD-sen2 AM
VIFBUFF-AM
—
—
—
—
—
—
—
—
—
—
—
—
SD sensitivity
—
—
—
IF buffer output
—
—
—
No. 6039-21/50
LA1784M
Usage Notes
1. Notes on V and Ground
CC
Pin 40
Pin 25
Pin 14
Pin 61
* Pin 6
Pin 3
VCC for the FM IF, AM, NC, MPX, and MRC blocks
Ground for the FM IF and AM blocks
Ground for the NC, MPX, and MRC blocks
V
V
CC for the FM front end, AM first mixer, and first oscillator blocks
CC for the FM front end and AGC blocks, and the AM/FM switching pin
Ground for the FM front end, first mixer, and first oscillator blocks
2. Notes on AM Coil Connection
The V used for the first oscillator coil connected to pin 7 must be at the same potential as pin 61.
CC
Connect to the IFT connected with pin 45, and to the MIX coil connected with pin 54. V must be at the same potential
CC
as pin 40.
3. AM/FM Switching
Pin 6 is also used as the FM front end and RF AGC V
CC
Pin 6 voltage
Mode
FM
8
OPEN
AM
Fig. 1
4. Notes on the FM Front End
Notes on interference rejection characteristics
• Intermodulation characteristics
The LA1784M applies two high-band AGC functions to prevent IM (the generation of intermodulation). These are
the narrow AGC (pin 58: mixer input detection type) and the wide AGC (for the pin 55 input), and this results in the
antenna frequency characteristics shown in figure 2. The levels at which the AGC functions turn on are determined
by the capacitors attached at pins 55 and 58.
∆f — AGC Sensitivity
When ∆f = 0, 98.1 MHz
110
100
The wide AGC
sensitivity when
90
pin 39 is 5 V.
80
70
The narrow AGC
sensitivity when
pin 39 is at ground.
60
50
–3
–2 –1
0
1
2
3
4
5
–5
–4
∆f
—
MHz
Fig. 2
No. 6039-22/50
LA1784M
• Notes on second-channel attenuation suppression
Keyed AGC (3D AGC) is a technique for achieving good characteristics for both intermodulation and second-
channel attenuation at the same time. When the desired signal is faint or nonexistent, the high-band AGC level will
be essentially 0, and as a result automatic tuning may malfunction and blocking oscillation may occur in the
presence of strong interfering stations. Keyed AGC helps resolve these problems.
This 3D AGC technique uses information that has the following three frequency characteristics and is a unique
Sanyo-developed system for determining the high-band AGC level.
RF and ANT circuit information: Mixer input AGC
Mixer circuit information: Mixer output AGC
CF selectivity information: S-meter output
• 3D AGC Features
Feature
Merit
Only the narrow AGC sensitivity (operation at ∆f < 1.5 MHz) is
controlled by the field strength of the desired station.
• Effective in resolving second-channel attenuation problems.
The narrow AGC sensitivity is controlled by a voltage (V23) that is
under 0.5 V.
• Allows effective resolution of second-channel attenuation problems without
degrading three-signal characteristics.
• Seek operations may stop incorrectly due to the occurrence of
intermodulation.
• It is possible to prevent the occurrence of intermodulation in the RF tuning
circuit and antenna in the presence of strong interfering stations, and
blocking oscillation due to AGC operation can be prevented.
The wide AGC can operate even when V23 = 0 (when the desired
station is not present).
The narrow and wide AGC sensitivities can be set independently.
(See figure 3 and 4.)
• Settings can be optimized for the field conditions.
• Since the narrow AGC operates for the desired station and adjacent
stations, the wide AGC sensitivity can be lowered and AGC malfunction
due to local oscillator signal can be prevented.
The system has two AGC systems: narrow and wide AGC.
(See figure 5.)
∆f — AGC on Level (ANT input)Fig.4
∆f — AGC on Level (ANT input)
Fig.3
Pin 55 capacitor: 3 pF
110
100
110
100
90
90
80
70
60
50
Pin 55 capacitor: 10 pF
Pin 58 capacitor:
10 pF
80
keyed AGC
keyed AGC
70
39
39
Pin 58 capacitor:
47 pF
60
5V
50
–3
–2 –1
0
1
2
3
4
5
–3
–2 –1
0
1
2
3
4
5
–5
–4
–5
–4
∆f
—
MHz
∆f
—
MHz
W-AGC, N-AGC — f
Fig.5
70
80
90
100
110
120
AGC input level frequency
characteristics such that
130
140
VRFAGC (pin 2) falls under 2 V.
7
2
3
5
7
2
3
5
7
100
2
3
5
1.0
10
Frequency, f — MHz
No. 6039-23/50
LA1784M
3D AGC Sensitivity Characteristics
AGC sensitivity
Wide AGC sensitivity
∆F
1
2
Second-channel
attenuation improvement
Narrow AGC sensitivity
3
Desired station AGC sensitivity
4
V
(Desired station field strength)
23
A12075
Fig. 6
Figure 6 3D AGC Sensitivity — ∆f, V characteristics
23
• The wide AGC sensitivity is determined by the antenna and RF circuit selectivity, regardless of V .
23
• The narrow AGC sensitivity is determined by the following.
The total selectivity of the antenna, RF circuit, and mixer when V ≥ 0.5 V
23
The above selectivity and V when V < 0.5 V
23
23
• The improvement in the second-channel attenuation corresponds to the area occupied by the narrow AGC in the
total AGC sensitivity area.
Figure 8 on the next page shows the actual operation of the circuit.
∆f — AGC on Level (ANT input)
110
f
= 98.1 MHz
Second-channel pad
D
100
90
80
70
60
50
ANT IN
V
IN
fu = 98.1 MHz + ∆f
A12076
–3
–2 –1
0
1
2
3
4
5
–5
–4
∆f
—
MHz
Fig. 7
No. 6039-24/50
LA1784M
7. Notes on 3D AGC (Keyed AGC)
V
CC
W-AGC
DET
55
N-AGC
DET
58
S-meter
90µA
+
–
V
CC
+
–
1
2
+
39
24
ANT
DUMPING
VS-meter
A11763
Fig. 8
• The antenna damping current from the pin due to the pin diode flows when the V2 pin reaches the V - V
CC
BE
level.
• The narrow AGC operates as follows.
When pin V39 > pin V24: The narrow AGC turns off.
When pin V39 < pin V24: The narrow AGC turns on.
No. 6039-25/50
LA1784M
• The LA1784M includes two AGC circuits in its front end block.
— Antenna input limiter using a pin diode.
— FET second gate control
The AGC input pin is pin 59, and the AGC circuit turns on when a signal of about 30 mVrms is input.
AGC activation
The pin diode drive circuit turns on when V – V2 is greater than or equal to about 1 V, and input limitation is
CC
applied to the antenna circuit. In application circuits, there will be an attenuation of about 30 to 40 dB. Next, when
an adequate current flows in the antenna attenuator pin diode, the inductance falls, the FET second gate voltage
drops, the FET gm falls, and the AGC operates. The recommended FET is the Sanyo 3SK263, which is an
enhancement-type MOSFET. Therefore, full AGC is applied when the voltage, V , between the second gate and
G2-S
the source is 0. Note that if a depletion-type MOSFET is used, AGC will not be applied unless V
is less than 0.
G2-S
V2 AGC Characteristics
Fig.9
9
8
7
6
5
4
3
2
1
fr = 98.0 Hz
V
= 8 V
CC
Ta = 25°C
Range where AGC level AGC level due
the AGC does due to the
to the MOSFET
second gate:
about 35 dB
not operate
pin diode:
about 35 dB
0
–10
0
10 20 30 40 50 60 70 80 90 100 110 120 130 140
ANT IN
— dBµ
• Mixer
The mixer circuit in this IC is a double-balanced mixer with both
balanced input and balanced output.
Input circuit type
64
59
60
63 62
Emitter input
Input impedance: 25 Ω
Due to optimized device geometry, emitter current, the bias, this IC
achieves the following performance.
MIX
Mixer input usable sensitivity: 15 dBµ
Mixer input IMQS: 90.5 dBµ
(For an oscillator level of 200 mVrms)
OSC
* The mixer input IMQS is defined as:
fr = 98.8 MHz, no input
fu1 = 98.8 MHz, 1 kHz, 30% modulation
fu2 = 99.6 MHz, no modulation
The interference 1 and 2
input levels such that
generated intermodulation
output signal-to-noise ratio
becomes 30 dB when an
interference signal with the
same level as the mixer input
is input, and distortion occurs
in the mixer.
Mixer circuit
Fig. 10
A12077
No. 6039-26/50
LA1784M
• Oscillator
Figure 11 shows the type of oscillator circuit used in this IC. It includes both an oscillator and an oscillator buffer.
V
CC
18pF
4
25pF
20pF
AM/FM
OSC BUFFER OUT
5
VT
A12078
Fig. 11
• Figure 12 shows the type of FM first IF amplifier used in this IC. It is a differential single-stage amplifier.
330Ω
TO MIX
FM IF input
56
53
330Ω
+
–
330Ω
A12079
Fig. 12
Specifications
Input impedance: 330 Ω
Output impedance: 330 Ω
Gain: 20 dB
No. 6039-27/50
LA1784M
5. FM IF
• Notes on the FM SD and SD adjustment
The figure below presents an overview of the FM SD and the IF count buffer.
+
–
R
R
4.9V
+
–
R
Band
muting
Muting
drive
output
HOLE
CLET
STEREO
IND
S-meter
IF count buffer
+
–
FM IF
39
24
33
23
26
5V
IF count output
SD
STEREO/MONO
2.5V 5V
Fig. 13
A11759
Figure 14 shows the relationship between the FM SD, the IF count buffer output, the S-meter, and the muting drive
output.
Larger
S-meter
V
V
V
values
of R
24
38
33
33
Smaller values of R
33
V
V
33
over 0.7 V
33
over 0.7 V
V
26
5 V
On as an
SD signal
SD
ON
SD
ON
Mono
0.7 V
Stereo
V
23AC
IF count
buffer
OFF
OFF
IF counter output off
2.5 V
V
23DC
5 V
0 V
RDS and other types of SD detection can be used by switching these modes.
New LA1784M functionality: For stereo input (when the V26 pin voltage is 0.7 V),
when this pin is shorted to ground (0.1 V or lower)
the IC will operate in forced mono mode.
A11758
Fig. 14
No. 6039-28/50
LA1784M
• Transient response characteristics during automatic tuning
The transient characteristics for SD and IF count buffer on/off operation are determined by the time constants of
the RC circuits attached to the following pins.
(1) Muting time constant: pin 33
(2) S-meter time constant: pin 24
(3) AFC time constant: pin 34
There are two points that require consideration when using fast tuning.
(1) The SD time constant due to the S-meter time constant
Since the current I24 (pin 24) varies with the field strength, the time constant also changes. There is no hysteresis
in the comparator.
If C24 is made smaller and the pin 24 voltage is used for the keyed AGC pin 23, C23 must be chosen so that
AGC during keyed AGC operation does not become unstable.
S-meter
SD comparator
I
24
R
24
C
24
24
A12080
Fig. 15
(2) The SD time constant due to the pin 33 muting voltage time constant
The changes in volume due to field fluctuation during weak field reception can be made smoother by setting the
attack and release times during soft muting operation.
Mute
drive
Mute
amp
Muting time constants
Attack: 10 kΩ × C33
Release: 50 kΩ × C33
10kΩ
50kΩ
Attack
Release
33
C
33
A11766
Fig. 16
SD Sensitivity Adjustment
Fig.17
50
40
30
20
10
0
6
10
14
18
22
26
30
34
Resistance between the pin and ground — kΩ
No. 6039-29/50
LA1784M
However, when testing this stop sensitivity, note that when checking the waveform on the IF count buffer output
(pin 23), there are cases, such as that shown below, where current in the test system may be seen as flowing to
ground and cause oscillation that causes the IF count buffer output to go to the output state.
IF buffer
amp
F.E.
IF
0.022 µF
5 V
Test system capacitance
The 10.7 MHz feeds back through ground.
A12081
Fig. 18
• FM Muting control pin (pin 47) (R47: 30 kΩ variable resistor)
The –3 dB limiting sensitivity can be adjusted with R47.
FM Soft Muting (1)
Fig.19
R47 = 7.5 kΩ
DET out
15 kΩ
20 kΩ
10 kΩ
Antenna input — dBµ
• FM muting attenuation adjustment (pin 58)
The muting attenuation can be switched between the three levels of –20, –30, and –40 dB by the resistor inserted
between pin 58 and ground. (Note that the exact values depend on the total tuner gain.)
The noise convergence with no input is determined by the pin 58 voltage.
58
R58
Open
Mute ATT
–20 dB
–30 dB
–40 dB
200 kΩ
30 kΩ
100Ω
R
58
A11764
The attenuation can be set by making R33 smaller as listed
in the table above.
33
R
33
A11765
Fig. 20
No. 6039-30/50
LA1784M
FM Soft Muting (2)
Fig.21
FM Soft Muting (3)
Fig.22
R47 = 7.5 kΩ
R47 = 7.5 kΩ
DET out
DET out
10 kΩ
10 kΩ
15 kΩ
20 kΩ
15 kΩ
200 kΩ
30 kΩ
2 0kΩ
Antenna input — dBµ
Antenna input — dBµ
V
CC
Mute amp.
(VCA)
Quadrature detector
200 kΩ
R
R
+
–
+
–
N-AGC
Mute
drive
Limiter
R
58
33
31
DET out
To MIX out
Open
200 kΩ
30 kΩ
A11767
Fig. 23
• FM muting off function
Forcing this pin to the ground level turns muting off.
Detector
output
0
1
When the pin is at the ground level, the noise convergence will
be 10 dB and the –3 dB limiting sensitivity will be about 0 dBµ.
20
Antenna input
A12082
Fig. 24
No. 6039-31/50
LA1784M
• Hall detection
The Hall detection function detects the level of the pin 36 quadrature input signal and then applies peak detection
to that result. The result is output from pin 33. This circuit has three effects.
(1) It assures that muting will be applied for weak inputs with an antenna input of under 5 dBµ. The amount of
attenuation is referenced to an antenna input of 60 dBµ, fm = 1 kHz, and a 22.5 kHz dev output, and is variable
from 10 dB to 40 dB when there is no input. Thus one feature of this circuit is that the weak input noise
attenuation and the –3 dB limiting sensitivity for over 5 dBµ inputs can be set independently.
Hall Detection Output — Antenna Input Characteristics Fig.25
5
Area muted by Hall detection
4
3
2
1
0
–20
–10
0
10
20
30
Antenna input
— dBµ
(2) When the pin 36 quadrature input is a saturated input, the pin 36 noise level (Va) is detected and a peak-hold
function is applied to pin 33 (Vb) for locations rapid field strength variations and severe multipath occurs for
fields that result in an antenna input level of over 5 dBµ.
36
33
Vb
+
Va
0.1µF
0
0
A12083
Fig. 26
(3) Unique features
One unique feature of the LA1784M is that if there are adjacent stations such that f = 98.1 MHz and f =
1
2
97.9 MHz, a search operation will not stop at 98.0 MHz. Since V
= 0 V and V = 3.6 V at 98.0 MHz in
SM
AFC
the situations shown in figure 27 and 28, even though Hall detection would normally not operate and SD would
be high, in this IC the Hall detection circuit will operate, V
will be set to 1.2 V (over 0.7 V) and the SD
Mute
signal will go low, thus preventing incorrect stopping of the search.
No. 6039-32/50
LA1784M
Unique Features of the LA1784M Hall Detection Circuit (1) Fig.27
Unique Features of the LA1784M Hall Detection Circuit (2) Fig.28
2
1
2 When the tuner is moved in 50 kHz steps.
With a 51 kΩ resistor between pins 37 and 34.
1 With the SD sensitivity adjusted to be 20 dBµ.
When the tuner is moved in 50 kHz steps.
With a 51 kΩ resistor between pins 37 and 34.
With the SD sensitivity adjusted to be 20 dBµ.
f
1
ANT
IN
f
2
0
0
–1
6
–1
6
4
2
0
6
4
2
4
2
0
6
4
2
0
8
6
4
f
= 97.9 MHz, 120 dBµ
0
8
6
4
2
2
f
= 97.9 MHz, 40 dBµ
2
fm = 400 Hz, 22.5 kHz dev.
fm = 400 Hz, 22.5 kHz dev.
f
= 98.1 MHz, 120 dBµ
1
f
= 98.1 MHz, 40 dBµ
1
fm = 1 kHz, 22. 5kHz dev.
fm = 1 kHz, 22.5 kHz dev.
2
0
0
97.7
97.8
97.9
98.0
98.1
98.2
98.3
97.7
97.8
97.9
98.0
98.1
98.2
98.3
Frequency, fr — MHz
Frequency, fr — MHz
• Notes on the quadrature input level
When a strong field is being received the quadrature signal input (pin 36) requires a 200 mV rms input, and the
detection transformer and the damping resistor between pins 36 and 37 must be designed.
(We recommend the Sumida SA-208 transformer and a 10 kΩ resistor between pins 36 and 37.)
When the pin 36 input level falls below 160 mV rms, the Hall detection circuit operates and the pin 33 mute drive
output voltage increases. Therefore, when pin 36 input is from 160 to under 200 mV rms during strong field
reception, the muting circuit may or may not operate due to sample-to-sample variations between individual ICs.
Furthermore, the SD function may not operate, and the audio output level may be reduced. Incorrect operation due
to sample-to-sample variations and temperature characteristics can be prevented by keeping the pin 36 voltage at
200 mVrms or higher.
SA208 + LA1784M IF Input Characteristics Fig.30
Pin 33 VMute — QD Input Level Fig.29
6
5
4
3
2
4 0.8
With pins 34 and 37 shorted.
With 5 V applied to pin 24.
3 0.6
2 0.4
1 0.2
THD 1 kHz
75 kHz dev
–100 –80 –60 –40 –20
–120
0
20 40 60 80 100 120
∆f
—
kHz
With the resistor between
pins 36 and 37 open.
–0.2
–0.4
75 Ω
0.022 µF
75 Ω
∆f=0→
+
10.7 MHz
With a 10 kΩ resistor
SG
between pins 36 and 37.
1
0
–0.6
–0.8
36
37
Voltage between pins 37 and 34
(referenced to the pin 37 voltage)
10.7 MHz
96
94
LA1888M
100 102
92
98
104
106
QD input level — dBµ
No. 6039-33/50
LA1784M
Detector output Pin 36 AC level
MPX OUT
R36-37
Open
10 kΩ
Vo
QDIN
330 mVrms
280 mVrms
235 mVrms
200 mVrms
• Band Muting Adjustment Procedure
The muting bandwidth can be modified as shown in figure 31 with the resistor R
between pin 34 and 37.
BW
R
BW
— Muting Bandwidth
Fig.31
280
240
200
160
120
80
R
BW
+
+
1 µF
0.47 µF
SA208
Sumida
34
10 kΩ
37 36
35
ANT IN 98 MHz 100 dBµ
40
0
2
3
5
7
2
3
5
7
100
2
1.0
10
Resistor R
between pins 34 and 37 — kΩ
BW
6. AM
• AM AGC system
The LA1784M RF AGC circuit takes its input from three sources: the WIDE AGC pin (pin 46), the MIDDLE
AGC pin (pin 49) and NARROW AGC. There is also an IF AGC circuit.
R
W
1st MIX 10.7MHz CF
2nd MIX 450kHz CF
IF Amp.
DET
62
49
52
31
RF
V
CC
CC
42
44
1st OSC
X'tal
240 kΩ
2.2 µF
V
Amp.
IF AGC
46
Middle AGC IN
Narrow AGC IN
Wide AGC IN
ANT
damping
RF AGC
57
48
Fig. 32
+
+
47 µF
3.3 µF
A11762
No. 6039-34/50
LA1784M
AM AGC f characteristics Fig.33
100
Wide AGC
Operates for wide
band interference
Wide AGC
Operates for
wide band
90
interference
Middle AGC
Middle AGC
Operates for
Operates for
80
interference within
±70 kHz of the
received frequency.
interference within
±70 kHz of the
received frequency.
70 Narrow AGC
Operates at the
received frequency.
60
1000
900
1100
1200
800
Frequency — Hz
Wide Band AGC Circuit
Fig.34
120
Received frequency:
1 MHz
30 Ω
0.022 µF
46
110
100
90
50 Ω
50 Ω
–6dB
0.022 µF
SG
ANTD
510 Ω
0.022 µF
80
70
1.0
2
3
5
7
10
2
3
5
Pin 46 input — MHz
The wide band AGC circuit in this IC has the frequency characteristics shown above. The pin 46 input frequency
characteristics are identical to those of the RF amplifier gate. This AGC circuit serves to prevent distortion at the
FET input when a strong signal is applied to the antenna circuit. The level at which the AGC circuit turns on can be
adjusted to an arbitrary level with the wide band AGC adjustment resistor. A delayed AGC on level can be handled
by reducing the value of the adjustment resistor.
Wide band AGC adjustment resistor
30 Ω
0.022 µF
V
CC
620 Ω
1MH
100 µH
FC18
57
62
100 µH
+
Fig. 35
A12084
No. 6039-35/50
LA1784M
• Notes on AM SD (pin 26) and the SD adjustment pin
SD and the IF buffer are operated by comparing the S-meter level (V24) and the 5 V reference voltage as shown in
figure 36.
S-meter
AM IF
Comparator
V
CC
+
–
IF buff amp.
50 pF
50 µA
55
100 kΩ
24
23
26
100 kΩ
0.47 µF
0.022 µF
IF buffer
5 V
51 kΩ
5 V
SD
Seek
Fig. 36
A12085
Figure 37 shows the relationship between the AM SD, the IF count buffer, and the S-meter.
Larger
values
S-meter
V
24PIN
of R
55
V
V
55
26
Smaller values of R
55
SD on
V
23AC
23DC
IF buffer on
5 V
OFF
V
Pin 55: AM SD adjustment pin
0 V
A11760
Fig.38
AM SD Sensitivity Adjustment
80
70
60
50
40
30
20
10
0
0
10
20
30
40
50
Resistance between pin 55 and ground — kΩ
No. 6039-36/50
LA1784M
• AM high band cut and detector output level adjustment methods
The pin 31 AM and FM tuner output has an impedance of 10 kΩ in AM mode and a few tens of Ohms in FM
mode. Therefore, R31 is used to lower the AM detector output level and C31 determines the AM high band
frequency characteristics.
V
CC
FM
detector
31
R31
C31
V
CC
+
AM
detector
10 kΩ
30
Noise
canceler
input
50 kΩ
A12086
Fig. 39
• AM stereo system pins
To the AM stereo decoder
V
CC
GND
400 mV rms
450 kHz output
IFT
45
39
V
CC
50 pF
150 Ω
Keyed AGC
IF AMP.
Fig. 40
A11761
No. 6039-37/50
LA1784M
• AM low band cut adjustment method
The AM low band frequency characteristics can be adjusted with C42, which is inserted between pin 42 and V
.
CC
Since the detector is designed with V as the reference, C42 must be connected to V
.
CC
CC
Detector Output — Frequency Fig.42
20
10
80%mod
V
0.1 µF
CC
With no
C42
C
used.
31
0
42
30%mod
0.022 µF
0.047 µF
0.1 µF
–10
–20
–30
C31pin
= 6800 pF
50 kΩ
50 kΩ
10 kΩ
+
–
10 kΩ
To pin 31
AM
detector
Using SEP 450H
C
=
42pin
10 kΩ
A12087
Fig. 41
–40
–50
fr = 100 kHz
fm = 10 kHz 30%mod
3
5
7
2
3
5
7
2
3
5
7
2
3
5
7
2
0.01
0.1
1.0
10
Frequency — Hz
7. Noise Canceler Block
• The noise canceler input (pin 30) has an input impedance of about 50 kΩ. Check the low band frequency
characteristics carefully when determining the value of the coupling capacitor used. Note that f will be about 3 Hz
C
when a 1 µF capacitor is used in the application.
• Pins 8 and 9 are used to set the noise detector sensitivity and the noise AGC. It is advisable to first set the noise
sensitivity for a medium field (an antenna input of about 50 dBµ) with pin 8 (the noise sensitivity setting pin), and
then set the AGC level for a weak field (20 to 30 dBµ) with pin 9 (the AGC adjustment pin). If the noise sensitivity
is increased, the AGC will become more effective but, inversely, the weak field sensitivity will be reduced.
Noise canceler 10 kHz overmodulation malfunction may be a problem. In particular, when an overmodulated
signal is input, the noise canceler may, in rare cases, malfunction. This is due to the fact that the IF detector output
has a waveform of the type shown in figure 43 due to the bands of the IF ceramic filters as shown below. (Here, the
antenna input is 60 dBµ, the ceramic filters are 150 kHz × 1 and 180 kHz × 2, f = 10 kHz, 180 kHz dev.) The noise
canceler reacts to the spikes (whiskers) generated due to this overmodulation, which results in distortion to the
audio output. (The spike components due to overmodulation occur due to the bands of the ceramic filters in the
tuner.) The following describes a method for resolving this problem. This incorrect operation due to
overmodulation is prevented by removing the spike components due to this overmodulation with a low-pass filter
consisting of a 1 kΩ resistor and a 2200 pF capacitor shown in figure 44. However, note that the FM separation
characteristics in the high band and the AM frequency characteristics will change.
H1 W1
2.5OU
IF audio output
f = 10 kHz,180 kHz dev
IF output
31
Noise canceler input
1 kΩ
–
30
1 µF
2200 pF
A12089
Fig. 44
–2.5OU
–19.00 µs
981.00 µs
Fig. 43
A12088
No. 6039-38/50
LA1784M
8. Multiplexer Block
• HCC (high cut control) frequency characteristics (pin 41)
When the HCC function operates, the frequency characteristics of the output signal are determined by the
capacitance of the external capacitor connected to pin 41.
20 kΩ
To the
VO
matrix
(dB)
41
C
A12090
Fig. 45
f
1
(Hz)
2πC × 20 kΩ
1
f = ——————— [Hz]
A12091
C
Fig. 46
2π × C × 20 kΩ
Frequency Characteristics Fig.47
Changes in the pin 41 capacitor capacitance (for a 100% high cut ratio)
0.001 µF
10
0
–10
–20
–30
–40
0.0022 µF
0.0047 µF
V
= 8.0 V
CC
–50
–60
f = 98 MHz 100%mod
80 dBµ IN
3
5
7
2
3
5
7
2
3
5
7
10k
2
3
100
1k
Frequency, f — Hz
• Pilot canceler adjustment (pins 17 and 18)
Noise
30
–
To the
multiplexer
canceler
input
Fig. 48
Gate
Pilot
cancel
11
12 17
18
6800 pF 3.9 kΩ 0.01 µF 50 kΩ
A12092
The pilot canceler signal waveform (pin 19) is a 19 kHz signal that contains no third harmonic as shown in figure
48. Since this signal has the same phase as the pilot signal, no capacitor is required between pin 18 and ground.
Since it has no third harmonic component, excellent pilot cancellation can be acquired in both the left and right
channels by adjusting with a variable resistor.
No. 6039-39/50
LA1784M
• Separation adjustment (pin 19)
5 kΩ
To the
Larger
subdecoder
19
20 kΩ
0.047 µF
A12094
C
Fig. 49
A12093
The separation is adjusted by modifying the input level to the subdecoder with the variable resistor connected to
pin 19. Since only the sub-modulation level is changed by changing the variable resistor setting, the monaural
(main) output level is not changed. Furthermore, degradation of high band separation in the decoder can be avoided
if the impedance of the external capacitor (C) in the subchannel frequency band (23 to 53 kHz) is made sufficiently
smaller than the variable resistor.
9. MRC Circuit
V
CC
2 µA
100 Ω
FM
S-meter
S-meter
DC buffer
MRC
QMRC
30 kΩ
6.4 kΩ
10 kΩ
75 pF
3.6 kΩ
1 kΩ
24
32
27
Noise amplifier
High-pass filter with
Fc = 70 kHz + amplifier
+
+
C27
V
CC
An external transistor equivalent
to the 2SC536 is required
To the SNC, pin 28
Reason: A QMRC level shifter is
required to allow a simplified MRC
circuit to be used in the LA1781M.
A11768
Fig. 50
No. 6039-40/50
LA1784M
(1) When there is no AC noise on pin 32
V
24
= V –V
27
BE
↑
Q
MRC
V27 is about 2.5 V when the antenna input is 60 dB or higher.
(2) Since the MRC noise amplifier gain is fixed, the MRC circuit is adjusted by reducing the AC input level.
32
+
Fig. 51
A11769
(3) The MRC attack and release are determined by C27 on pin 27.
Attack: 7 µA · C27 → 2 µA · C27
Release: 500 Ω · C27 → 100 Ω
Notes on the Noise Canceler
The noise canceler characteristics have been improved by implementing the circuit that determines the gate time in
logic. Since the time constant in earlier noise cancelers was determined by an RC circuit such as that shown in figure
52, the rise time shown in figure 53 was influenced by the values of the resistor and capacitor used. As a result the
noise exclusion efficiency was reduced by this delay in the rise time. In the LA1784M, this rise time was shortened by
implementing the circuit that determines the gate time in logic, allowing it to reliably exclude noise.
A11772
A11771
Fig. 53
Fig. 52
No. 6039-41/50
LA1784M
Gain Distribution (FM)
This section investigates the gain in each block in the LA1784M when the Sanyo recommended circuits are used.
(Test conditions)
Ambient temperature: 26°C
Antenna and mixer input frequency: 98.1 MHz
First and second IF input frequency: 10.7 MHz
The input levels when V = 2 V will be as follows.
SM
ANT IN: 19 dBµ
MIX IN: 30 dBµ
1st IF IN: 42 dBµ
2nd IF IN: 60 dBµ
When the gains for each block are determined according to the above, the results are as follows.
RF GAIN: 11 dB
MIX GAIN: 12 dB
1st IF GAIN: 18 dB
1st IF IN 56 pin
FM
MIX IN 64 pin
RF
ANT IN
2nd IF IN 51 pin
11 dB
12 dB
18 dB
A11773
Fig. 54
No. 6039-42/50
LA1784M
(AM)
This section investigates the gain in each block in the LA1784M when the Sanyo recommended circuits are used.
(Test conditions)
Ambient temperature: 26°C
Antenna and mixer input frequency: 1 MHz
First and second mixer input frequency: 10.7 MHz
Second IF input frequency: 450 kHz
The gains at each stage will be as follows.
RF Gain (ANT IN-pin62): 17 dB
1st MIX Gain (pin62-pin56): 8 dB
1st IF Gain (pin55-pin53): 15 dB
AM
1st MIX
1st IF
2nd MIX
2nd IF
AM DET
RF
RF
Gain
1st MIX
Gain
1st IF
Gain
2nd MIX
Gain
2nd IF
Gain
A11774
Fig. 55
No. 6039-43/50
LA1784M
Input Circuits for Each Stage
[FM]
• Mixer input
• First IF input
0.022 µF
75 Ω
0.022 µF
300 Ω
75 Ω
63
64
56
75 Ω
75 Ω
V
IN
fr = 10.7 MHz
Actual
A11776
measurement
A11775
• IF input
0.022 µF
75 Ω
300 Ω
51
50
75 Ω
330 Ω
0.022 µF
fr = 10.7 MHz
A11777
[AM]
• First mixer input
• Second mixer input
0.022 µF
50 Ω
0.022 µF
50 Ω
50 Ω
62
49
50 Ω
fr = RF
fr = 10.71 MHz (f2nd osc + 0.45 MHz)
A11778
A11779
IFT
• IF input
• Del input
0.022 µF
50 Ω
0.022 µF
50 Ω
50 Ω
50 Ω
52
45
fr = 450 kHz
fr = 450 kHz
A11780
A11781
No. 6039-44/50
LA1784M
Sample AM tuner Circuit with the LC72144 Used Together
2nd MIX
IF
CF
CF
CF
RF
450K
1st IF
300 Ω
XBUFF
fosc
LC72144
A11782
AM 1st IF
10.7 MHz
10.8 MHz
Step
FM IF
1
2
f
OSC 10.25 MHz
OSC 10.35 MHz
10 kHz, 11 kHz
9 kHz, 10 kHz
10.7 MHz
10.8 MHz
f
1st MIX
IF
10.71 MHz
10 kΩ
CF
CF
CF
RF
AF
62
59
60
56
53
49
54
52
1st OSC
2nd OSC
Lch
31
NC
MPX
Rch
10.26 MHz
IF
10.7 MHz
AF
CF
CF
Quadrature
detector
RF
63
64
60
59
56
53
51
A11783
No. 6039-45/50
LA1784M
Crystal Oscillator Element
Kinseki, Ltd.
Frequency: 10.26 MHz
CL: 20 pF
Model No.: HC-49/U-S
Coil Specifications
Sumida Electronics, Ltd.
[AM Block]
AM FILTEER (A286LBIS-15327)
AM OSC (V666SNS-213BY)
S
1
2
3
3
2
1
4
6
4
6
AM IF1 (7PSGTC-5001A=S)
AM IF2 (7PSGTC-5002Y=S)
3
4
3
4
2
2
S
1
6
1
6
S
S
S
AM loading (269ANS-0720Z)
AM ANT IN (385BNS-027Z)
3
4
3
4
2
2
1
6
1
6
S
S
AM RF amplifier (187LY-222)
0.1ø2UEW
[FM Block]
FM RF (V666SNS-208AQ)
FM ANT (V666SNS-209BS)
S
3
2
1
4
3
2
1
4
6
6
S
FM OSC (V666SNS-205APZ)
FM MIX (371DH-1108FYH)
S
3
2
1
4
C1
8
3
2
1
4
6
7
C2
6
S
FM DET (DM6000DEAS-8407GLF)
S
3
S
4
2
1
6
No. 6039-46/50
LA1784M
The Toko Electric Corporation
[AM Block]
AM FILTEER
AM OSC
3
4
6
1
2
3
4
2
1
0.1ø2UEW
6
AM IF1
AM IF2
3
2
1
4
6
3
2
1
4
6
0.05ø3UEW
0.05ø3UEW
AM loading
AM ANT IN
3
2
1
4
3
2
1
4
6
6
0.05ø3UEW
0.06ø3UEW
AM RF amplifier
0.1ø2UEW
[FM Block]
FM RF
FM ANT
3
2
1
4
S
3
2
1
4
ø0.1–2UEW
ø0.1–2UEW
S
6
S
6
FM OSC
FM MIX
3
2
1
4
S
3
2
1
4
6
5
6
ø0.07–2UEW
S
ø0.12–2UEW
S
FM DET
3
4
2
1
6
0.07ø2MUEW
No. 6039-47/50
LA1784M
Antenna input — dBµ
Antenna input — dBµ
Input — dBµ
Antenna input — dBµ
Antenna input — dBµ
Input — dBµ
First IF input — dBµ
Mixer input — dBµ
No. 6039-48/50
LA1784M
Frequency, — MHz
Frequency, — MHz
Ambient temperature, Ta — °C
Ambient temperature, Ta — °C
AM I/O Characteristics
20
V
= 8.5 V
CC
f = 1 MHz
mod = 1 k 30%
OUT
0
–20
–40
–60
NOISE
–80
–100
–20
0
20
40
60
80
100
120
140
Ambient temperature, Ta — °C
ANT input, IN — dBµ
AM Distortion
AM DC Characteristics
7.0
6.0
5.0
4.0
3.0
2.0
7.0
6.0
5.0
4.0
3.0
2.0
V
= 8.5 V
V
= 8.5 V
CC
RF AGC
CC
f = 1 MHz
f = 1 MHz
mod = 1 k 30% 80%
1.0
0
1.0
0
–20
0
20
40
60
80
100
120
140
–20
0
20
40
60
80
100
120
140
ANT input, IN
— dBµ
ANT input, IN
— dBµ
No. 6039-49/50
LA1784M
AM Second-Channel Interference
Rejection Characteristics
AM Second-Channel Interference
Rejection Characteristics
20
0
20
0
∆40 kHz
∆400kHz
100 dBµ
100 dBµ
desire mod ON
desire mod ON
80 dBµ
80 dBµ
–20
–40
–20
–40
40 dBµ
40 dBµ
desire
mod
OFF
desire
mod
OFF
60 dBµ
60 dBµ
15pF
15pF
50/3Ω
ANT IN
50/3Ω
ANT IN
f
= 1 MHz
D
50Ω
50/3Ω
–60
–80
50Ω
50/3Ω
–60
–80
f
=1MHz
D
30Ω
65pF
fm = 1 kHz 30%
30Ω
65pF
fm=1kHz 30%
V
V
50Ω 50/3Ω
IN
50Ω 50/3Ω
IN
fu=1040kHz
fu = 1400 kHz
JIS ANT. DUMMY
120 140
fm=400Hz 30%
JIS ANT. DUMMY
120 140
fm = 400 Hz 30%
40
60
80
100
40
60
80
100
ANT input, IN
— dBµ
ANT input, IN
— dBµ
Specifications of any and all SANYO products described or contained herein stipulate the performance,
characteristics, and functions of the described products in the independent state, and are not guarantees
of the performance, characteristics, and functions of the described products as mounted in the customer’s
products or equipment. To verify symptoms and states that cannot be evaluated in an independent device,
the customer should always evaluate and test devices mounted in the customer’s products or equipment.
SANYO Electric Co., Ltd. strives to supply high-quality high-reliability products. However, any and all
semiconductor products fail with some probability. It is possible that these probabilistic failures could
give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire,
or that could cause damage to other property. When designing equipment, adopt safety measures so
that these kinds of accidents or events cannot occur. Such measures include but are not limited to protective
circuits and error prevention circuits for safe design, redundant design, and structural design.
In the event that any or all SANYO products (including technical data, services) described or contained
herein are controlled under any of applicable local export control laws and regulations, such products must
not be exported without obtaining the export license from the authorities concerned in accordance with the
above law.
No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying and recording, or any information storage or retrieval system,
or otherwise, without the prior written permission of SANYO Electric Co., Ltd.
Any and all information described or contained herein are subject to change without notice due to
product/technology improvement, etc. When designing equipment, refer to the “Delivery Specification”
for the SANYO product that you intend to use.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not
guaranteed for volume production. SANYO believes information herein is accurate and reliable, but
no guarantees are made or implied regarding its use or any infringements of intellectual property rights
or other rights of third parties.
This catalog provides information as of June, 2001. Specifications and information herein are subject to
change without notice.
PS No. 6039-50/50
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