SANYO LA1776M

Ordering number : ENN8085
SANYO Semiconductors
DATA SHEET
LA1776M
Monolithic Linear IC
Single-Chip Tuner IC for Car Radios
Overview
The LA1776M 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
Feature
•
•
•
•
•
•
•
•
•
•
•
•
Reduced noise in the mixer and amplifier blocks for improved performance
Increased FM front end mixer dynamic range for improved three signal characteristics
Improved AM practical sensitivity and saturated signal-to-noise ratio
S-meter sample-to-sample variations can be improved by using the FM S-meter shift function (Fixed resistors can
be used for the SD, keyed AGC, muting on adjustment, muting attenuation, SNC, and HCC.)
High-speed searching can be implemented using the FM band mute time constant switching function.
Superb listenability provided by improved medium and weak field noise canceller characteristics.
Improved separation temperature dependency characteristics
Excellent FM S-meter voltage linearity
Noise rejection improved by modifications to the NC circuit
Sample-to-sample variation correction circuit (zapping) in the FM IF circuit
Stopping at stations with heavy interference is prevented by increasing the AM wide AGC sensitivity by 10 dB
during seek operations
Built-in anti-birdie filter
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
40706 MS OT B8-7756 No.8085-1/41
LA1776M
Specifications
Maximum Ratings at Ta = 25°C
Parameter
Maximum supply voltage
Allowable power dissipation
Symbol
Conditions
VCC1 max
Pins 5, 40, and 61
VCC2 max
Pins 9, 46, 54, 59, and 60
Pd max
Ratings
Unit
9
Ta ≤ 85°C
V
12
V
950
mW
Operating temperature
Topr
–40 to +85
°C
Storage temperature
Tstg
–40 to +150
°C
Recommended Operating Conditions at Ta = 25°C
Parameter
Maximum Recommended supply voltage
Operating supply voltage range
Symbol
VCC
VCCST IND
Conditions
Ratings
Unit
Pins 5, 9, 40, 46, 54, 59, 60, and 61
8
V
Pin 39
5
V
7.5 to 8.5
V
VCC op
Function List
FM Front End (Equivalent to the Sanyo LA1193)
• Double input type double balanced mixer, base injection
• Pin diode drive AGC output
• MOSFET second gate drive AGC output
• Keyed AGC adjustment pin
• Differential IF amplifier
• Wide band AGC sensitivity setting pin, and narrow band AGC sensitivity setting pin
FM IF
• IF limiter amplifier
• S-meter output (also used for AM) 6-stage pickup
• Multipath detection pin (shared FM signal meter)
• Quadrature detection
• AF preamplifier
• AGC output
• Band muting
• 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)
• Time constant switching during band muting
• S-meter shifter
Noise Canceller
• 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
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 function
• SNC (stereo noise controller)
No.8085-2/41
LA1776M
• Stereo display pin
• Anti-birdie filter
AM
• Double balanced mixer
• IF amplifier
• Detection
• RF AGC (narrow/wide)
• Pin diode drive pin
• IF AGC
• 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
• Detection output frequency characteristics adjustment pin (low cut, high deemphasis)
• AM stereo buffer
MRC (multipath noise rejection circuit)
AM/FM switching output (linked to the FM VCC)
No.8085-3/41
LA1776M
Operating Characteristics at Ta = 25°C, VCC= 8.0V, with the specified test circuit and for standards other than
Sanyo's for the FM IF input
Ratings
Parameter
Symbol
Conditions
min
typ
max
unit
[FM Characteristics] At the FM IF input
Current drain
ICCO-AM
Demodulation output
VO-FM
Pin 31 demodulation output
VO-31
Channel balance
Total harmonic distortion
CB
No input, I9 + I40 + I46 + I54 + I59 + I60 + I61
78
93
112
mA
10.7 MHz, 100dBµ, 1 kHz, 100%mod, The pin 15 output
205
310
415
mVrms
10.7 MHz, 100dBµ, 1 kHz, 100%mod, The pin 31 output
190
295
380
mVrms
The ratio between pins 15 and 16 at 10.7 MHz, 100 dBµ, 1 kHz
–1
0
+1
dB
0.3
1
THD-FM mono
10.7 MHz, 100 dBµ, 1 kHz, 100% mod, pin 15
Signal-to-noise ratio: IF
S/N-FM IF
10.7 MHz, 100 dBµ, 1 kHz, 100% mod, pin 15
68
76
dB
AM suppression ratio: IF
AMR IF
dB
Muting attenuation
Separation
10.7 MHz, 100 dBµ, 1 kHz, fm = 1 kHz, 30% AM, pin 15
55
68
Att-1
10.7 MHz, 100 dBµ, 1 kHz. The pin 15
attenuation when V33 goes from 0 to 2 V
5
10
15
dB
Att-2
10.7 MHz, 100 dBµ, 1 kHz. The pin 15
attenuation when V33 goes from 0 to 2 V*1
16
21
26
dB
Att-3
10.7 MHz, 100 dBµ, 1 kHz. The pin 15
attenuation when V33 goes from 0 to 2 V*2
26
31
36
dB
10.7 MHz, 100 dBµ, L+R = 90%, pilot = 10%. The pin 15 output
ratio
30
40
Separation
Stereo on level
ST-ON
The pilot modulation such that V39< 0.5 V
2.3
3.5
Stereo off level
ST-OFF
The pilot modulation such that V39> 3.5 V
0.6
1.6
Main total harmonic distortion
%
THD-Main L
10.7 MHz, 100 dBµ, L+R = 90%, pilot = 10%. The pin 15 signal
0.3
dB
5.5
%
%
1.2
%
Pilot cancellation
PCAN
10.7 MHz, 100 dBµ, pilot = 10%.
The pin 15 signal/the pilot level leakage. DIN audio
SNC output attenuation
AttSNC
10.7 MHz, 100 dBµ, L-R = 90%, pilot = 10%.
V28 = 3 V → 0.6 V, pin 15
4
8
12
dB
AttHCC-1
10.7 MHz, 100 dBµ, 10 kHz, L+R = 90%, pilot = 10%.
V29 = 3 V → 0.6 V, pin 15
2
6
10
dB
AttHCC-2
10.7 MHz, 100 dBµ, 10 kHz, L+R = 90%,
pilot = 10%. V29 = 3 V → 0.1 V, pin 15
7
11
15
dB
100 dBµ, 10.7 MHz, 30% modulation. The IF input such
that the input reference output goes down by 3 dB
35
42
49
dBµ
The IF input level (unmodulated) when V33 = 2 V
45
53
61
dBµ
The IF input level (unmodulated) (over 100 mV rms)
such that the IF counter buffer output goes on
72
80
88
dBµ
HCC output attenuation
Input limiting voltage
Muting sensitivity
SD sensitivity
Vi-lim
Vi-mute
SD-sen1 FM
SD-sen2 FM
IF counter buffer output
Signal meter output
Muting bandwidth
Mute drive output
20
30
dB
Unmodulated IF input such that the SD pin goes to the on state
72
80
80
dBµ
VIFBUFF-FM
10.7 MHz, 100 dBµ, unmodulated. The pin 23 output
150
230
300
mVrms
VSM FM-1
No input. The pin 24 DC output, unmodulated
0.1
0.3
V
VSM FM-2
60 dBµ. The pin 24 DC output, unmodulated
0.6
1.2
1.8
V
VSM FM-3
80 dBµ. The pin 24 DC output, unmodulated
2.0
2.7
3.5
V
VSM FM-4
110 dBµ. The pin 24 DC output, unmodulated
4.5
5.2
5.9
V
BW-mute
100 dBµ. The bandwidth when V33 = 2 V, unmodulated
150
220
290
kHz
VMUTE-0
No input. The pin 33 DC output, unmodulated
1.8
2.5
3.3
V
VMUTE-100
100 dBµ, 0 dBµ. The pin 33 DC output, unmodulated
0
0.1
0.2
V
N-AGC on input
VN-AGC
83 MHz, unmodulated.
The input such that the pin 2 voltage is 2.0 V or below
83
90
97
dBµ
W-AGC on input
VWAGC
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.)
98
104
110
dBµ
[FM FE Mixer Input
Conversion gain
Oscillator buffer output
A.V
VOSCBUFFFM
83 MHz, 80 dBµ, unmodulated. The FE CF output
90
140
220
mVrms
No input
85
110
165
mVrms
V24 = 5 V
2.9
3.0
3.1
V
The pin 26 input level at f = 70 kHz such that
pin 24 goes to 5 V and pin 27 goes to 2 V
35
55
70
mVrms
[Multipath Rejection Circuit] MRC input (pin 27)
MRC output
MRC operating level
VMRC
MRC-ON
Continued on next page.
No.8085-4/41
LA1776M
Continued from preceding page.
Ratings
Parameter
Symbol
Conditions
min
typ
max
unit
[AM Characteristics] AM ANT input
Practical sensitivity
S/N-30
1 MHz, 30 dBµ, fm = 1 kHz, 30% modulation, pin 15
20
Detector output
VO-AM
1 MHz, 74 dBµ, fm = 1 kHz, 30% modulation, pin 15
140
210
280
mVrms
VO-AM31
1 MHz, 74 dBµ, fm = 1 kHz, 30% modulation, pin 31
130
190
260
mVms
VAGC-FOM
1 MHz, 74 dBµ, referenced to the output, the input amplitude
such that the output falls by 10 dB. Pin 15
51
56
61
dB
50
Pin 31 detector output
AGC F.O.M.
Signal-to-noise ratio
S/N-AM
1 MHz, 74 dBµ, fm = 1 kHz, 30% modulation
Total harmonic distortion
THD-AM
1 MHz, 74 dBµ, fm = 1 kHz, 80% modulation
Signal meter output
Oscillator buffer output
Wide band AGC sensitivity
SD sensitivity
IF buffer output
dB
56
dB
0.3
1
%
V
VSM AM-1
No input
0.0
0.1
0.5
VSM AM-2
1 MHz, 130 dBµ, unmodulated
3.9
4.9
6.8
VOSCBUFF AM
No input, the pin 15 output
185
230
W-AGCsen1
1.4 MHz, the input when V48 = 0.7 V
89
95
101
W-AGCsen2
1.4 MHz, the input when V48 = 0.7 V (seek mode)
80
86
92
dBµ
SD-sen1 AM
1 MHz, the ANT input level such that the IF counter output turns on.
24
30
36
dBµ
SD-sen2 AM
1 MHz, the ANT input level such that the SD pin goes to the on state.
24
30
36
1 MHz, 74 dBµ, unmodulated. The pin 23 output
180
220
VIFBUFF-AM
V
mVrms
dBµ
dBµ
mVrms
Note: These measurements must be made using the either the IC-51-0644-692 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.
Package Dimensions
Unit:mm
Allowable power dissipation,
Pdmax – mW
3159A
Mounted on a 40 × 18 × 1.3 mm3
glass epoxy printed circuit board
Ambient temperature, Ta – ºC
No.8085-5/41
AC2
AC4
AC3
65pF
300Ω
50Ω
VD 1
FM RF AGC
50Ω
50Ω
VA6
AN Vcc
50Ω
100µH
15pF
30Ω
0.022µF
50Ω
30MH
75Ω
FC18G
620Ω
100kΩ
0.022µF
1MH
470Ω
15pF
15pF
GND
SW8
SW7
30kΩ 200kΩ
+
47µF
0.022µF
13kΩ
0.022µF
100µH
30Ω
18kΩ
100kΩ
470Ω
FE Vcc
1000pF
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
SW3
0.022µF
SW2
3pF
470Ω
0.022µF
330Ω
AM
IF2
AM
IF2
AMIF
AGC
+
ANT D
1
LEVEL
DET
AM
X OSC
Vsm
3
30kΩ
44
4
5
FM OSC
AM OSC
N-AGC
W-AGC
KEYED
AGC
AM
W AGC
AM
N AGC
ANT D
AM RF
AGC
drive
FM OSC
BUFF
FM Vt
2
45
+
3.3µF
68kΩ
MUTE
AM OSC
BUFF
AM/FM MIX
FM RF
AGC
1st IF
AMP
46
AMDET
AMLC
47
56kΩ
AM MIX AM
48
+
3.3µF
1µF
CF OUT
SVC208
18pF
VA6
4pF
7
NC
AGC
+
0.022µF
0.022µF
NC
LPF
FM Vsm
s mut
H det
FM AFC
VA1
HPF OUT
VA9
11
38
22kΩ
12
SNC
2SC536
VA10
LPF OUT
10µF
33
16
Sub De
coder
MATRIX
pilot
can
pilot
det
tri
ger
MRC
noise
amp
time
const
MRC
out2
2.2µF
0.022µF
L-ch
VA3
15
FF
19K
VCO
14
,
X TAL
13
Main
HC
FF
FF
38K
34
9pF
+
phase
comp
AM/FM
SW
REG
FE
VCO
stop
FM/AM
SD
ST IND
REG
AM
IF
count
SW
REG
FM IF
MUTE
35
IF
count
AMP
36
1kΩ
REG
NC.MPX
REG
2.7V
37
HCC
0.1µF
6800pF 0.01µF
10.25MHz
10
30kΩ
AM Vt
9
8
+
GATE
TRIG
REG
BUFF
Mute
ATT
control
MUTE
AMP.
Q.DET
39
+
1µF
+
FM 8V
AM 0V
40
+
100kΩ
5V
SD/ST IND
0.022µF
VD2
100µF
2SC536 OSC Buffer
SW1
10µF
6
ECL
ECL
ECL
ECL
ECL
Zap
IF AMP
IF AMP
IF AMP
IF AMP
IF AMP
41
39kΩ
MUTE
drive
NC
HPF
42
+
IF AMP
43
10kΩ
20pF 25pF
0.01µF 3kΩ
1µF
2MΩ
R-ch
VA4
0.015µF
GND
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
0.22µF
022µF
8V
2SK212
0.22µF
0.047µF
VR2 100kΩ
CSB
912JF108
0.01µF
SW9
20kΩ
VR1
+
+
100kΩ
100kΩ
SW4
1000pF
8200pF
10µF 1kΩ
+
0.022µF
+
+
+
300pF
+
0.015µF
VCC
4.3kΩ
Mute D
FMS
VD5
SW10
VA8
0.01µF VCO OUT
IF Buffer
VA2
SW5 SW6
5V
50kΩ 1kΩ
Vcc3
PG1
AC1
Vcc2
50kΩ
Vsm
MRC IN
MRC OUT
VD4
SNC
HCC
022µF
VA11
DET OUT
+
0.022µF
KETED AGC
LA1776M
LA1776M AC Test Circuit
No.8085-6/41
AM VCC 8V
100µH
0.022µF
75Ω
1000pF
+
1000pF
470Ω
+
AM/FM ANT IN
FE GND
100Ω
0.1µF
1000pF
0.022µF
15pF 15pF
100µH
AM IF IN1
FM IF IN1 57
56
54
FM WB AGC
AM SD ADJ
55
AM MIX OUT
64
63
62
61
FE VCC
10pF
MIX IN
10pF
MIX IN
AM MIX IN
FE VCC
AM/FM VT
0.001µF
59
MIX OUT 60
MIX OUT
47pF
IN
FM NB AGC
MUTE ATT
58
SVC208
220kΩ
52
51
AM IF OUT
FM IF OUT
53
AF AGC
100kΩ
100kΩ
49
AM IF IN2
50
AM 2nd
MIX IN
220Ω
0.022µF
30MH
AM ANT
1000pF
1000pF
15pF
0.022µF
620Ω
100kΩ
SVC208
0.022µF
30Ω
0.022µF
100kΩ
22µF
1MH
100kΩ
200Ω
100µH
180Ω
33Ω
FC18G
100kΩ
12pF
100kΩ
100Ω
0.022µF
AM IF IN
100kΩ
AM
IF1
AM
IF2
AMIF
AGC
ANT D
65kΩ
1
LEVEL
DET
AM
X OSC
Vsm
+
2
AGC
44
4
6
ECL
ECL
ECL
ECL
ECL
Zap
40
+
NC
LPF
FM Vsm
s mute
H det
FM AFC
9
8
+
GATE
TRIG
AM/FM
OSC BUFF
30kΩ
7
NC
AGC
IF AMP
IF AMP
IF AMP
IF AMP
IF AMP
41
MUTE
drive
NC
HPF
42
+
IF AMP
43
10kΩ
AM/FM SW
5
FM OSC
AM OSC
N-AGC
W-AGC
KEYED
AGC
AM
W AGC
AM
N AGC
ANT D
AM RF
AGC
drive
AM OSC
BUFF
3
45
+
MUTE
AM OSC
BUFF
AM/FM MIX
FM RF
AGC
1st IF
AMP
46
AMDET
AMLC
47
AM MIX AM
48
AM ANT D
AM WAGC IN
1µF
FM ANT D
100kΩ
min:5kΩ
8pF
RF AGC
BYPASS
FM RF1µF AGC
3.3µF
MUTE ON
ADJ
AM IF AGC
FM OSC
KEYED AGC
33pF 22pF
1000pF 33kΩ
1µF
NOISE AGC
SEN
150kΩ
FM SD ADJ
3
1
PILOT DET
AM LC
AGC ADJ
100µF
2
–
+
0.47µF
AM/FM
OSC BUFF
300pF
0.022µF
10
REG
BUFF
Mute
ATT
control
MUTE
AMP.
Q.DET
39
AM/FM SD
ST IND
HOLD
+
AM OSC
100kΩ
6800pF
56kΩ
11
38
+
LPF OUT
AM IFT
FE GND
SVC208
18pF
1µF
0.022µF
12
SNC
13
Main
HC
FF
FF
38K
15
FF
19K
VOC
14
34
phase
comp
FM/AM
SW
FM/AM
SD
ST IND
+
9pF
IF
COUNT
SW
10.25kHz IN
REG
FE
REG
AM
REG
FM IF
SW
35
1.3kΩ
IF
COUNT
AMP
VCO
stop
36
REG
NC.MPX
REG
2.7V
37
30kΩ
HCC
0.01µF
VCC
8V
10.25M IN
2.2µF
0.022µF
MUTE DRIVE
33
L-ch
16
Sub De
coder
MATRIX
pilot
can
pilot
det
tri
ger
MRC
noise
amp
time
const
MRC
out2
VREF 2.7V
5V
R-ch
HCC
NC IN
8200pF
68kΩ
0.22µF
1000pF
30kΩ
+
VCO
PHASE COM
+
PHASE COM
IF COUNT
BUFFER
0.22µF
AM/FM VSM
GND
GND
VCC
CSB
912kHz
SEP ADJ
19
20kΩ 0.047µF
100kµ
18
PI CAN
OUT
17
PI CAN 0.01µF
IN
20
21
22
23
24
25
MRC OUT 3.3µF
27
MRC
GAD
ADJ
26
3.3µF 51kΩ
SNC
28
29
30
DET OUT
31
0.22µF
FM VSM
32
0.015µF
AFC IN
PLL IN
+
+
NC,MPX GND
+
MPX OUT L
+
0.015µF
MPX OUT R
+
ST IND
AM/FM SD
5/2.5/0V
IF Buffer
FM/AM VSM
47kΩ
0.022µF
LA1776M
LA1776M Application Circuit Example
No.8085-7/41
LA1776M
Pin Descriptions
Pin No.
Pin
Description
Equivalent circuit
VCC
62 pin
ANT
RF
AGC
1000 pF
1
FM antenna damping
drive pin
An antenna damping current flows when the RF
AGC voltage (pin 1) reaches VCC – VD.
500 Ω
100 Ω
1
1000 pF
VCC (61pin)
FET
2ND GATE
+
12 kΩ
2
ANT
DAMPING
Used to control the FET second gate voltage.
2
RF AGC
In AM mode, forcibly set the pin 2 voltage to the low
level and apply AGC to the FM RF system.
N
AGC
DET
W
AGC
DET
VCC-VD
KEYED
AGC
3
EF. GND
VCC
VCC (5 pin)
10 kΩ
4
Oscillator connection
4
FM OSC
This pin is designed to drive an external oscillator
circuit that uses external transistors and capacitors.
25 pF
VT
2 kΩ
20 pF
Continued on next page.
No.8085-8/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
The pin 5 input voltage state (high or low) switches
between AM and FM modes.
Equivalent circuit
VCC
+
–
5
+
AM/FM
switching circuit
V5 = high (8 V): FM
5
AM/FM SW
FM OSC
V5 = low (0 V): AM
This level is also used as the FM oscillator circuit
VCC.
4V
8V
3
GND
3 kΩ
15 kΩ
3 kΩ
1 kΩ
6
7
Noise AGC sensitivity
AGC adjustment
200 Ω
After setting up the medium field (about 50 dBµ)
sensitivity with the noise sensitivity setting pin (pin
6), set the weak field (about 20 to 30 dBµ) sensitivity
with the AGC adjustment pin (pin 7)
6
7
3 kΩ
+
2 MΩ
0.01 µF
FM OSC
8
AM/FM oscillator buffer
output
0.022 µF
AM OSC
This pin is shared by the AM and FM systems.
8
9
VCC (16 pin)
AM system first oscillator
9
AM OSC
This oscillator can provide frequencies for use up to
the shortwave band.
This pin includes an ALC circuit.
A L C
Continued on next page.
No.8085-9/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
0.01µF
12
10
11
Memory circuit
connection
6800 pF
11
10
VCC
Recording circuit used during noise canceller
operation.
Differential
amp
Gate
circuit
LPF
VCC
30 kΩ
PLL
12
Pilot input
Pin 12 is the PLL circuit input pin.
N.C
11
12
0.01 µF
10 kΩ
5.6 V
Crystal oscillator circuit
13
AM 2nd OSC
20 pF
to 2nd
MIX
33 pF
Use the HC-49/U-S manufactured by Kinseki, Ltd.
CL = 20 pF
13
X tal
10.26 MHz
14
N. C, MPX, MRC, GND
Ground for the N, C, MPX, and MRC circuits
Continued on next page.
No.8085-10/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
VCC
AM output
FM multiplex output
15
16
MPX output (left)
MPX output (right)
For deemphasis, use the following capacitors:
3.3 kΩ
3.3 kΩ
50 µS: 0.015 µF
75 µS: 0.022 µF
15
16
0.015 µF
0.015 µ F
VCC
50 kΩ
17
Pilot canceller signal
input
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
10 kΩ
17
18
0.01 µF
50 kΩ
VCC
18
Pilot canceller signal
output
Pin 18 is the output pin for the pilot canceller signal.
300 Ω
17
330 Ω
18
0.01 µF
50 kΩ
Continued on next page.
No.8085-11/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
DECODER
Composite
signal
19
Separation adjustment
pin
10 kΩ
Use a trimmer to adjust the subdecoder input level.
(The output level is not modified in mono and main
modes.)
19
20 kΩ
0.01 µF
CSB
912
JF108
20
VREF
20
VCO
The oscillator frequency is 912 Hz.
JF108
VREF
21
22
6 kΩ
PHASE COMP
6 kΩ
+
19 kHz
∠90º
21
22
+
+
Continued on next page.
No.8085-12/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
+
–
FM SD
23
IF counter buffer
seek/stop switching
AM SD
3.3 V
3.3 V
This pin functions both as the IF counter buffer (AC
output) and as the seek/stop switch pin.
FM mode
+
–
+
–
FM SD
1.3 V
5 V (high): Seek mode
2.5 V: High-speed SD mode
0 V (low): Reception mode
AM mode
23
51 kΩ
5 V (high): Seek mode
0 V (low): Reception mode
STOP
2.5 V/5V
VCC
24
FM
S-meter
AM/FM signal meter
32
Fixed-current drive signal meter output
32
10 kΩ
AM
S-meter
Dedicated FM signal
meter
24
10 kΩ
The LA1776M supports two methods: detecting IF Smeter wideband components and detecting the
noise canceller high-pass filter noise output.
26
MRC AC input
AM/FM
SW
30 kΩ
C1
R2
26
The noise amplifier gain is determined by R2 and the
internal 30 kΩ resistor as shown in the figure. Note
that the frequency characteristics are determined by
C1.
+
–
Dedicated MRC
S-meter voltage
VCC
VCC
7 µA
27
MRC output
The MRC detector time constant is determined by a
100 Ω resistor and C2 when discharging and by the
7-µA current and C2 when charging.
C2
+
27
100 Ω
28 pin
Continued on next page.
No.8085-13/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
VCC
28
SNC control input
The sub-output is controlled by a 0 to 1-V input.
28
VCC
29
HCC control input
The high-frequency output is controlled by an input
in the 0 to 1 V range.
32
29
+
1000 pF
1 µF
VCC
30
Noise canceller input
The input impedance is about 50 kΩ.
31
+
0.22 µF
30
50 kΩ
4.2 V
Continued on next page.
No.8085-14/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
VCC
FM
detector
output
31
10 kΩ
Pin 30 is the noise canceller input. The input
impedance is 50 kΩ
R
VCC
30
+
Noise canceller input
Pin 31 is the AM and FM detector output
31
AM/FM detector output
In FM mode, this is a low-impedance output.
AM
detector
output
0.22 µF
In AM mode, the output impedance is 10 kΩ.
The AM detection output can be modified by
adjusting the value of R.
30
Noise
canceller
50 kΩ
VCC
VSM
32
32
IF S-meter output
FM S-meter output block
1000 pF
10 kΩ
29
C1
0.022 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
Mute drive output
• Noise convergence adjustment
The noise convergence when V33 is 2 V will be
about 40 dB.
(The basis can be varied from 5 to 35 dB for a 1
kHz 22.5 kHz deviation output.)
33
VCC
SEEK
OFF
MUTE
AMP.
10 kΩ
50 kΩ
*: There is no hole detection function.
• Muting off function
The muting function is turned off by a 4 kΩ resistor
between pin 33 and ground.
SOFT
MUTE
Band
muting
SD circuit
Continued on next page.
No.8085-15/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
VCC
R2
37
VCC
Vref: 2.7 V
QD output
35
34
VCC
VCC
VCC
Null voltage
34
35
36
36
When tuned, the voltage between pins 34 and 37,
V34 – 37, will be 0 V.
The band muting function turns on when |V34 – 37| ≥
0.7 V.
Quadrature
detector
IF limitter amplifier
R1: Resistor that determines the width of the band
muting function
R1
+
When R1 is larger ... The band becomes narrower
C34
C38
When R1 is smaller ... The band becomes wider
38
Band muting time
constant switching
The band muting time constants are determined by
the following components.
During reception: R1, C34, and C38
38
37
34
500 Ω
During seek: R1 and C34
Band
muting
During FM
reception: on
The band muting time constant can be made smaller
by reducing the value of C34. Degradation of total
harmonic distortion characteristics at low
temperatures can be prevented by make C38 larger.
V23 is switched by the voltage mode as described
below.
FM mode
39
AM/FM SD pin
Stereo indicator
5 V: V23 operates in conjunction with the SD
pin and IF counter buffer.
2.5 V: V23 operates as the forcible SD mode
pin.
0 V: Reception mode
AM/FM
SD
Stereo
indicator
Seek/stop
switching
39
AM mode (There are two modes: 0 V or 5 V.)
5 V: Linked operation with the seek SD pin.
2.5 V: Reception mode, no function.
0 V: Reception mode
5V
19
Continued on next page.
No.8085-16/41
LA1776M
Continued from preceding page.
Pin No.
40
Pin
VCC
Description
Equivalent circuit
IF, NC, MPX, VCC
R
SD Adj
38
41
FM SD
4V
The comparison voltage is controlled by an external
resistor.
20 kΩ
In seek mode, the seek operation will stop when V41
< Vsm.
+
–
SD
Comparator
24 Vsm
S-meter
VCC
19 kHz∠0º
BIAS
This pin us used for both FM pilot detection and AM
low-cut filter.
30 kΩ
30 kΩ
Pilot detection
42
Pilot detector
AM L.C
+
The system is forced to mono mode when a 1 MΩ
resistor is inserted between pin 42 and ground. In
AM mode, the frequency characteristics of the
unneeded audio band below 100 Hz are modified
producing a clear audio signal.
AM low-cut filter
30 kΩ
VCC
DET
The cutoff frequency fC can be determined from the
following formula.
3.3 kΩ
1 kΩ
+
–
FC = 1/2 π × 3.3 kΩ × C
3.3 kΩ
1kΩ
42
+ C
1 µF
Vsm
Dedicated keyed AGC S-meter
43
Keyed AGC
The keyed AGC function starts operation when V43
becomes less than or equal to 0.8 V. (Narrow AGC
off mode.)
1 kΩ
N-AGC
+
–
43
1 kΩ
0.8 V
Continued on next page.
No.8085-17/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
100 kΩ
44
44
FM muting on level
adjust
Modify the value of the external resistor to adjust the
muting on level.
soft mute
MUTE
2.7 V
30 kΩ
VCC
+
3.3 µF
C
48
45
TR1: Seek mode time constant switching diode
VCC
Discharge diode
• Reception
DET
3.3 kΩ
τ = 3.3 µF × 300 kΩ
45
IF AGC
• Seek
3.3 kΩ
τ = 3.3 µF × 10 Ω
500 Ω
IF
AGC
The external capacitors are connected to VCC.
This is because the IF amplifier operates referenced
to VCC.
TR1
SEEK
ON
10 Ω
300 kΩ
40 pin VCC
46
40 pin VCC
46
IF output
The IF amplifier load
DET
Continued on next page.
No.8085-18/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
VCC
RF AGC rectification capacitor
5.8 V
10 kΩ
The low frequency distortion is determined as
follows:
47
Increasing C47 and C56 improves the distortion
but makes the response slower.
47
56
RF AGC bypass
RF AGC
Reducing C47 and C56 aggravates the distortion
but makes the response faster.
*:If the audio is disturbed due to the RF AGC when
there are rapid changes in the reception field
strength (on the order of off to 80 dBµ), the
combination of the time constants due to C56 and
C47 must be changed.
–
+
+
Antenna
damping
3.3 µF
For AGC use
56
+
47 µF
5.7 V
10 kΩ
10 kΩ
50
51
FM IF input
IF bypass
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
330 Ω
51
0.022 µF
2 kΩ
100 Ω
52
IF input
The input impedance is 2 kΩ.
52
IF OUT
53
61 pin VCC
53
57
IF amplifier output
(AM/FM)
IF amplifier input
(AM/FM)
200 Ω
• First IF amplifier input pin
• Inverted output amplifier
The gain is switched between AM and FM modes
IF IN
57
300 Ω
3.75 V
Continued on next page.
No.8085-19/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
40 pin VCC
VCC 40 pin
54
OSC
54
49
AM MIX OUT
AM MIX IN
The mixer coil connected to the pin 54 mixer output
must be wired to VCC (pin 40).
The pin 49 mixer input impedance is 10 Ω
49
10.7 M
10.7 M
10 kΩ
W-AGC
62 pin
VCC
N-AGC
Pins 55 and 58 include built-in DC cut capacitors.
W-AGC IN
58
AM-SD Adj
The AGC on level is determined by the values of the
capacitors C1 and C2.
30 pF
Pin 55 functions as the SD sensitivity adjustment pin
in AM mode.
55
C1
V55 is changed by the value of the external resistor.
N-AGC IN
SD is operated by comparing V55 with the S-meter
voltage.
Seek mode stop condition: V55 < Vsm
50 pF
1.5 kΩ
MIX
IN
58
C2
20 kΩ
+
–
MIX
OUT
AM SD
S-meter
FM Vsm
VCC
50 pF
48
48
AM antenna damping
drive output
I48 = 6 mA
Wideband AGC input
Resistor values under 5 kΩ cannot be used for the
FM S-meter shift resistor.
FM S-meter voltage shift
Antenna damping current
100 Ω
0.022 µF
20 kΩ
I48
VCC
W.AGC AMP.
ANT DAMPING
DRIVER
Continued on next page.
No.8085-20/41
LA1776M
Continued from preceding page.
Pin No.
Pin
Description
Equivalent circuit
59
60
OSC
Y-type mixer circuit
59
60
62
FM/AM MIX output
AM MIX input
Pins 59 and 60 are the mixer outputs
62
10.7 MHz (10.71 MHz)
10 kΩ
Input impedance: 10 kΩ
V62 = 2.3 V
1ST.IF
O S C
59
Double balanced mixer
60
Pins 59 and 60 are the mixer 10.7-MHz output
59
60
63
64
Mixer output
Mixer input
30 Ω
Pins 63 and 64 are the mixer inputs
These are base injection type inputs.
VCC
Note: The lines for pins 63 and 64 must be kept
separated from the lines for pins 59 and 60.
63
10 pF
RF AMP
64
10 pF
No.8085-21/41
LA1776M
Test Conditions
Parameter
Symbol
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
SW9
ICCO-AM
OFF
B
OFF
B
—
ON
OFF
OFF
ON
—
Demodulation output
VO-FM
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
Pin 31 demodulation output
VO-31
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
CB
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
THD-FM mono
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
Signal-to-noise ratio: IF
S/N-FM IF
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
AM suppression ratio: IF
AMR IF
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
Att-1
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
Att-2
ON
B
OFF
B
—
ON
ON
OFF
ON
—
Att-3
ON
B
OFF
B
—
ON
OFF
ON
ON
—
Separation
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
Stereo on level
ST-ON
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
Stereo off level
ST-OFF
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
THD-Main L
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
Pilot cancellation
PCAN
ON
B
OFF
B
—
ON
OFF
OFF
OFF/ON
—
SNC output attenuation
AttSNC
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
HCC output attenuation 1
AttHCC-1
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
HCC output attenuation 2
AttHCC-2
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
VIN-LIM
ON
B
OFF
B
—
ON
OFF
OFF
ON
ON
Current drain
Channel balance
Total harmonic distortion (FM)
Muting attenuation
Separation
Main total harmonic distortion
Input limiting voltage
Muting sensitivity
SW10
VIN-MUTE
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
SD sensitivity 1
SD-sen1 FM
ON
B
OFF
B
OFF
OFF
OFF
OFF
ON
—
SD sensitivity 2
SD-sen2 FM
ON
B
OFF
B
ON
OFF
OFF
OFF
ON
—
VIFBUFF-FM
ON
B
OFF
B
OFF
OFF
OFF
OFF
ON
—
IF counter Buffer output
Signal meter output (FM)
Muting Bandwidth
Mute drive output
VSM FM-1
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
VSM FM-2
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
VSM FM-3
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
VSM FM-4
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
BW-mute
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
VMUTE-0
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
VMUTE-100
ON
B
OFF
B
—
ON
OFF
OFF
ON
—
N-AGC on input
VNAGC
ON
A
ON
B
—
ON
OFF
OFF
—
—
W-AGC on input
VWAGC
ON
A
ON
B
—
ON
OFF
OFF
—
—
Conversion gain
A.V
ON
A
ON
B
—
ON
OFF
OFF
—
—
VOSCBUFF-FM
ON
A
ON
B
—
ON
OFF
OFF
—
—
Oscillator buffer output
MRC output
VMRC
ON
—
OFF
B
—
ON
OFF
OFF
—
—
MRC-ON
ON
—
OFF
B
—
ON
OFF
OFF
—
—
Practical sensitivity
S/N-30
OFF
—
OFF
B
ON
ON
—
—
—
—
Detection output
VO-AM
OFF
—
OFF
B
ON
ON
—
—
—
—
Pin 31 detection output
VO-AM31
OFF
—
OFF
B
ON
ON
—
—
—
—
AGC F.O.M.
—
MRC operating level
VAGC-FOM
OFF
—
OFF
B
ON
ON
—
—
—
Signal-to-noise ratio
S/N-AM
OFF
—
OFF
B
ON
ON
—
—
—
—
Total harmonic distortion (AM)
THD-AM
OFF
—
OFF
B
ON
ON
—
—
—
—
VSM AM-1
OFF
—
OFF
B
ON
ON
—
—
—
—
VSM AM-2
OFF
—
OFF
B
ON
ON
—
—
—
—
VOSCBUFF-AM
OFF
—
OFF
B
ON
ON
—
—
—
—
W-AGCsen 1
OFF
—
OFF
B
ON
ON
—
—
—
—
W-AGCsen 2
OFF
—
OFF
B
ON
ON
—
—
—
—
SD-sen1 AM
OFF
—
OFF
B
OFF
OFF
—
—
—
—
SD-sen2 AM
OFF
—
OFF
B
OFF
OFF
—
—
—
—
VIFBUFF-AM
OFF
—
OFF
B
OFF
OFF
—
—
—
—
Signal meter output (AM)
Oscillator buffer output
Wide band AGC sensitivity
SD sensitivity
IF buffer output
No.8085-22/41
LA1776M
Usage Notes
1.AM/FM Switching
Pin 5 is used for switching between AM and FM (dedicated FM oscillator VCC)
FM mode: When the pin 5 voltage is greater than 4 V.
AM mode: When the pin 5 voltage is less than 4 V.
FM/AM SW
FM OSC
4
5
FM 8V/
FM OSC
FE GND
3
V5 VCC
2.Pin 39: AM/FM SD and Stereo Indicator
Pin 39 is used both for AM and FM station detection and as a stereo indicator.
AM/FM SW
FM mode
5 V: Operates as the SD pin, coupled to the IF counter buffer.
2.5 V: Operates in forced SD mode.
0 V: Reception mode
AM mode (two modes: 0 V and 5 V)
5 V: Operates coupled as the seek SD pin
2.5 V: Reception mode, no function
0 V: Reception mode
3.Front End
Notes on interface characteristics
Like the previous Sanyo products, the LA1776M includes the 3 D (triple dimension) AGC circuit. This circuit
allow the LA1776M to achieve at the same time both good three-signal interference characteristics (intermodulation
characteristics) and two-signal sensitivity suppression characteristics.
3-1. Intermodulation characteristics
The LA1776M prevents intermodulation from occurring by applying dual high-band AGC.
110
AGC on sensitivity
100
90
Wide AGC (47 p)
80
Keyed AGC (10 K)
70
Narrow AGC (47 p)
60
Center frequency: 98.1 MHz
Keyed AGC (43 pin) = 10 K
50
-5
-4
-3
-2
-1
0
∆ f [MHz]
1
2
3
4
5
No.8085-23/41
LA1776M
3-2. Two-Signal Sensitivity Suppression
Like the earlier Sanyo products, the LA1776M's 3D AGC determines the amount of wide-band AGC applied
using the information acquired from three frequency characteristics.
RF and antenna circuit information: Mixer input AGC
Mixer circuit information: Mixer output AGC
<- Three dimensions
CF selectivity: S-meter output
3-3. FE Block AGC
Like the earlier Sanyo products, the LA1776M uses the follow two functions
(1) PIN diode antenna input control
(2) FET second gate control
The AGC input pins are pin 58 (narrow AGC) and pin 55 (wide AGC).
Applying AGC
The PIN diode drive circuit is turned on when (roughly) (VCC – V2) is 1 V or higher.
In application circuits, there will be about 30 to 40 dB of attenuation. When an adequate current flows in the
antenna attenuator PIN diode and the impedance falls, the FET second gate voltage falls, the FET gm falls, and
the AGC operates. The recommended FET is the Sanyo 3SK263, which is an enhanced type MOSFET, and
thus the full AGC will be applied when the voltage between the second gate and the source (G2-S) is 0. Note
that if a depletion type MOSFET were used, AGC would not be applied unless VG2-S were lower than 0 V.
9
Pin 2 voltage
8
Region where the AGC
does not operate
AGC voltage – V
7
AGC amount due
to the PIN diode
6
AGC amount due
to the MOSFET's
second gate.
5
4
3
2
1
0
–20 –10
PIN diode voltage
0
10
20
30
40
50
60
70
80
90
100 110 120 130
Field strength - dBµ
3-4. Mixer
The LA1776M's mixer circuit is a double balanced mixer that used balanced signals for both the input and
output.
59
Input type: base input
Input impedance: 2 kΩ
60
OSC
2 kΩ
2 kΩ
63
64
No.8085-24/41
LA1776M
3-5. Mixer
Pin 4: The FM oscillator circuit is formed from external components.
Pin 8: AM/FM oscillator buffer
VCC
VCC
VCC
BUFF
4
AM OSC
VT
8
FM/AM OSC BUFF
3-6. FM: First IF Amplifier (10.7 MHz)
Input impedance: 330 Ω (pin 57)
Output impedance: 330 Ω (pin 53)
No.8085-25/41
LA1776M
4. FM IF
4-1. Notes on FM SD and SD Adjustment
The FM station detection and IF counter buffer operate with the following elements.
38
37
AFC
VCC
SEEK = OFF
ST IND
+
_AFC
1
1
2
13
2
12
+
_
FM S-meter
2.7 + 0.6 V
-0.6 V
4V
2.7 V
+
_
mute AMP
20 kΩ
2
VCC
30 kΩ
+
_SD
3
+
_
FM IF
Soft mute
mute ATT
41
1
SEEK = OF
44
33
23
mute on
39
IF conut
mute d
FM SD adj
IF conut
58
SD/ST
IF conut
200 kΩ 30 kΩ
5V
2.5 V
5V
The following conditions must be met for the station detection and IF counter buffer to operate.
(1) V24 > V41 - The S-meter voltage must be higher than the pin 41 voltage
(2) V33 < 0.7 V (Vbe) - The band muting function must not be operating.
(3) V23 = high - A high level (VDD) must be applied to pin 23 from a 51 kΩ resistor.
The figure below shows the relationships between the FM station detection, the IF counter buffer output, the Smeter voltage, and the muting operation output.
V24
Larger
values
of R33
S-meter
V38
V33
Smaller values of R33
V33
over 0.7 V
V33
over 0.7 V
V26
5V
SD
ON
SD as an
SD signal
SD
ON
Mono
Stereo
V23AC
OFF
V23DC
IF
count
buffer
OFF
IF counter output off
5V
2.5 V
0V
RDS and other types of SD detection can be used by switching these modes.
No.8085-26/41
LA1776M
4-2. Transient Response Characteristics During Automatic Selection
The transient response characteristics when the SD or IF counter buffer are turned on or off are determined by
the time constant at the pins shown below.
(1) AFC time constant – Pin 37
VCC
(2) Muting time constant – Pin 33
(3) S-meter time constant – Pin 24
(1) Station detection time constant due to the pin 37 AFC voltage
time constant
Since there is a function for switching the AFC time constant, it
is possible to set the time constants so that there are no harmful
effects. For reception mode, if the pin 38 capacitor value is not
made comparatively large, the total harmonic distortion may be
made worse.
• Reception mode time constant: Make the time constant longer
with R34_37, C37, and C38.
AFC
+
–
1 kΩ
FM STOP: ON
FM SEEK: OFF
Vref
34
37
38
R34-37
+
+
C34
C38
C37
• Seek mode time constant: A high-speed response can be
achieved with R34_37 and C37, since the seek mode time
constant is independent of C38.
• The following values are recommended.
C37: About 0.022 µF
C38: About 1 µF
(2) Station detection time constant due to the pin 33 muting voltage time constant
The volume changes due to fluctuations in the field during weak field reception can be made smoother by
setting the soft muting operation attack and release times appropriately.
MUTE
DRIVE
MUTE
AMP
10 kΩ
50 kΩ
Attack
Release
33
C33
(3) Station detection time constant due to S-meter time constant
Since the pin 24 current (I24) changes with the field strength, the time constant also changes. There is no
hysteresis in the comparator circuit. Note that if a smaller value is used for C24, the MRF frequency
characteristics setting will need to be changed as well.
FM S-meter
AM S-meter
10 kΩ
24
No.8085-27/41
LA1776M
4-3. FM Muting Function Control (pin 44: soft muting) and Attenuation Setting (pin 58)
The -3 dB limiting sensitivity can be adjusted by changing the value of R44.
The muting attenuation can be switched between three levels (-10, -20, and -30 dB) with R58.
Output level
When R44
is small
Output level
R58:OPEN
R58:200K
When R44 is large
R58:30K
V33
R58
Mute ATT
OPEN
–10 dB
200 K
–20 dB
30 K
–30 dB
5.AM Block
The LA1776M adopts an upconversion method.
5-1. AM AGC System
The RF AGC pickup operates according to the input level on pins 48 and 49.
Pin 48: AGC based on the components in the 10.7 MHz CF band.
Pin 49: Wideband AGC (The level at which the wideband AGC turns on can be adjusted with Rw.)
(The seek mode wideband AGC on level is increased by 10 dB.)
VCC
AM AGC SYSTEM
RW
1st MIX
62
RF
IF Amp.
10.7 MHz CF
57
57
10.7 MHz
49
2nd MIX
450 kHz CF
IF Amp.
52
31
DET
42
1st OSC
X'tal
+
1 µF
VCC
Middle AGC IN
IF AGC
49
Wide AGC IN
ANT
DUMPING
45
+
1 µF
RF AGC
56
+
47
22 µF
+
3.3 µF
The RF AGC is picked up from two places.
1. The wideband AGC determined by RW.
2. Midband AGC picked up from the second mixer at pin 49.
Operating bandwidth: 150 to 180 kHz (the 10.7 MHz CF
bandwidth)
No.8085-28/41
LA1776M
5-2. AM SD Pin (pin 39) and the AM SD Adjustment Pin
The LA1776M compares V24 and the reference voltage V55 to operate SD and the IF counter.
S-meter
AM IF
Comparator
VCC
+
–
IF Buff Amp.
50 pF
50 µA
55
24
23
39
100 kΩ
100 kΩ
0.47 µF
0.022 µF
51 kΩ
IF BUFER
5V
SD
SEEK
5V
Larger
values
of R55
V24PIN
S-meter
V55
Smaller values of R55
V39
SD ON
V23AC
OFF
IF Buffer ON
V23DC
5V
Pin 55: AM SD adjustment pin
0V
5-3. AM Wideband Cut and Detection Output Adjustment Methods
The AM/FM detection output (pin 31) has an output impedance of 10 kΩ in AM mode, and an impedance of a
few tens of ohms in FM mode. Therefore the AM detection output level is lowered by R31 and the AM
wideband frequency characteristics are determined by C31.
VCC
FM
detector
31
R31
VCC
C31
+
AM
detector
10 kΩ
Noise canceller
input
50 kΩ
30
No.8085-29/41
LA1776M
5-4. AM Low Region Cut Adjustment
The AM low frequency region frequency characteristics can be adjusted with capacitor C42, which is inserted
between pin 42 and ground. Since this capacitor is shared with the FM pilot detector, it is connected to ground.
To prevent incorrect operation of the pilot detector, C42 must have a value of 0.33 µF or higher.
Detector Output – f [dB]
5
1 kΩ
+
–
AM detector
10 kΩ
0
To 31PIN
Output [dB]
1 kΩ
Pilot det
42
–5
–10
C42
–15
C42 = 0.47u
–20
0.01
0.1
C42 = 1u
1
10
Modulation frequency [kHz]
6.Noise Canceller Block
6-1. The noise canceller input (pin 30) has an input impedance of about 50 kΩ. The low band frequency
characteristics require care when determining the value for the coupling capacitor. Note that fC will be about 3
Hz in an application that uses a 1 µF capacitor.
6-2. The noise detection sensitivity and the noise AGC are set with pins 8 and 9. Good settings can be acquired by
first setting the medium field strength (corresponding to an antenna input of about 50 dBµ) sensitivity with the
noise sensitivity setting pin (pin 8) and then setting the weak field (20 to 30 dBµ) with the AGC adjustment pin
(pin 9). Note that if the noise detection sensitivity is increased, the effect of the AGC will be improved, but that
inversely the weak field sensitivity will be decreased.
The problem of incorrect operation of the noise canceller for 10 kHz overmodulation occurs when an
overmodulated signal is input and the noise canceller responds to that signal even though it should not. The
cause of this is the IF detector output taking on the sort of waveform shown in the figure due to the band of the
IF ceramic filter as shown below. (150 kHz × 1, 180 kHz (r) 2, f = 10 kHz, 180 kHz deviation) The noise
canceller responds to the whisker components generated by this overmodulation, resulting in distortion of the
audio output. (The whisker components due to the overmodulation are generated by the band of the ceramic
filter in the tuner.) This can be prevented as follows. The incorrect operation due to the overmodulation can be
eliminated by removing the whisker components due to the overmodulation as described above with the lowpass filter consisting of a 1 kΩ resistor and 220 pF capacitor as shown in the figure. Note, however, 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
1 kΩ
31
2200 pF
–2.5OU
–19.00 µs
Noise canceller input
+ –
30
1 µF
981.00 µs
No.8085-30/41
LA1776M
7.Multiplex Block
7-1. Pilot Canceller
The pin 18 pilot canceller signal waveform is a 19 kHz signal in which the third harmonic is not present. Since
this signal has the same phase as the pilot signal, no capacitor is required between pin 18 and ground. Since the
third harmonic is not present, excellent pilot cancellation in both the left and right channels can be acquired by
adjusting the circuit with a variable resistor.
Noise canceller 30
input
To the
multiplexer
–
GATE
PILOT
CANCEL
10
11 17
6800 pF
18
0.01 µF 50 kΩ
7-2. Separation Adjustment (pin 19)
5 kΩ
To the
subdecoder
19
Larger
20 kΩ
0.047 µF
C
The separation is adjusted by adjusting the sub-decoder input level with the pin 19 variable resistor VR.
Adjusting VR only changes the sub-channel modulation. It does not change the monaural (main) output level.
Degradation of high band separation in the decoder can be avoided if the impedance of the external capacitor
value (C) is made enough smaller than the impedance of VR in the sub-channel signal frequency band (23 to 53
kHz).
8. MRC Block
7 µA
100 Ω
DC BUFFER
5.5 kΩ
MRC
5.5 kΩ
30 kΩ
FM/AM Vsm
FM Vsm
1 kΩ
10 kΩ
HPF: C26, 30K
LPF: C32
Gain: R26
24
C24
0.22 µF
+
32
26
C32
1000 pF
27
C26
3.3 µF
100 kΩ
R26
51 kΩ
+
C27
*: When the AC component is removed with C24.
No.8085-31/41
LA1776M
8-1. The S-meter DC input voltage is set by the variable resistor R1 connected to pin 32. While it is often said that a
curve such as that shown in figure 59 is ideal for separation control when multipath interference occurs, if the
pin 32 voltage is too high, separation control in strong field reception, as shown in figure 60, will become
impossible. Thus it is desirable to adjust the circuit so that the pin 32 voltage remains under 2 V when
saturated.
AC 30%
SEP (dB)
SEP (dB)
ACø%
AC 60%
AC 100%
Field strength
AC 30%
ACø%
AC 60%
AC 100%
Field strength
8-2. The time constant with which the MRC circuit controls the separation is determined by an internal 100 Ω
resistor and C2 during charge and by a constant current of 7 µA and C2 during discharge.
VCC
VCC
+
7 µF
C2
41
100 Ω
No.8085-32/41
LA1776M
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 FILTER (SA-1051)
AM OSC (SA-359)
S
1
2
4
3
3
2
6
1
4
AM IF1 (SA-264)
3
AM IF2 (SA-1063)
4
2
1
6
1
S
S
S
AM loading (SA-1062)
6
AM ANT IN (SA-1048)
4
3
4
2
2
1
4
3
S 2
3
6
1
6
6
S
S
AM RF amplifier (RC875-222J)
0.1ø2UEW
[FM Block]
FM RF (SA-1060)
FM ANT (SA-1061)
S
3
4
2
2
1
4
3
6
1
6
S
S
FM OSC (SA-1052)
FM MIX (SA-266)
S
3
4
3
C1
4
8
2
1
2
6
S
1
7
C2
6
S
FM DET (SA-208)
S
S
3
4
2
1
6
No.8085-33/41
LA1776M
The Toko Electric Corporation
[AM Block]
AM FILTER (A2861BIS-15327)
1
2
3
AM OSC (V666SNS-214BY)
3
4
2
6
1
4
AM IF1 (7PSGTC-5001A)
3
4
1
AM IF2 (7PSGTC-5002Y)
3
2
6 0.1ø2UEW
4
2
6 0.05ø3UEW
AM loading (269ANS-0720Z)
1
6 0.05ø3UEW
AM ANT IN (385BNS-027Z)
S
3
4
3
2
1
4
2
6 0.05ø3UEW
1
6
S
AM RF amplifier (187LY-222)
0.1ø2UEW
[FM Block]
FM RF (V666SNS-208AQ)
S 3
4
2
1
4
2
1
3
4
2
ø0.1 – 2UEW
6 S
FM OSC (V666SNS-205APZ)
3
FM ANT (V666SNS-209BS)
ø0.12 – 2UEW
6 S
ø0.1 – 2UEW
1
6 S
FM MIX (371DH-1108FYH)
S 3
4
2
5
1
6 S
ø0.07 – 2UEW
FM DET (DM600DEAS-8407GLF)
3
4
2
1
6 0.07ø2MUEW
No.8085-34/41
LA1776M
Sagami Elec Co., Ltd.
[AM Block]
AM FILTER (000021055)
AM OSC (000021056)
S
1
2
3
3
4
5.1 µH
2
6
1
4
AM IF1 (000021057)
3
AM IF2 (000021059)
3
4
6
4
180 pF
S 1
180 pF
2
2
6 S
1
6
S
AM loading (000021061)
3
AM ANT IN (000021062)
3
4
4
100 µH
30 mH
2
2
1
1
6
6
S
S
AM RF amplifier (000021063)
2.2 mH
[FM Block]
FM RF (000021064)
FM ANT (000021065)
S
3
3
4
105.5 nH
2
2
1
4
1
6
6
S
S
FM OSC (000021066)
FM MIX (000021067)
S
3
4
2
1
62.7 nH
3
4
2
5
1
6
1-2:100 pF
2-3:100 pF
6
S
S
FM DET (010021075)
S 3
4 S
1-3:20 µH
3-4:120 pF
2
1
6
No.8085-35/41
LA1776M
FM Input/Output Characteristics
FM Input/Output Characteristics
S
7
8
6
-10
Vsm
-20
5
-30
4
-40
3
AMR(1K,30%)
2
-50
N
-60
-70
-20 -10
0
10 20 30 40 50 60 70
1
0
90 100 110 120 130
80
RF AGC
7
6
5
4
3
2
ANT D
THD (100%)
1
0
-20 -10
10 20 30 40 50 60 70
0
Field strength – dB µ
4
10
8
S
0
3
-10
-20
SEP(R) SEP(L)
2
-40
Vsnc
7
6
-10
Output – dB
Separation, Sep – dB
Vsnc – V
0
1
Vsm
-20
5
-30
4
-40
3
2
-50
-60
N
1
-60
-70
-20 -10
0
10 20 30 40 50 60 70
0
90 100 110 120 130
80
-70
-20 -10
10 20 30 40 50 60 70
0
80
0
90 100 110 120 130
Field strength – dB µ
Field strength – dB µ
AM Input/Output Characteristics
AM Frequency Characteristics
8
2
6
output
7
0
5
6
-2
RF AGC
5
Output – dB
AGC – V
Total harmonic distortion, THD – %
90 100 110 120 130
AM Input/Output Characteristics
FM Separation Input/Output Characteristics
-50
80
Field strength – dB µ
10
-30
THD (30%)
4
THD (80%)
THD (30%)
3
4
THD (80%)
-4
3
2
-6
THD (30%)
2
ANT D
1
-8
1
0
-20 -10
0
10
20
30
40
50
60
70
80
90 100 110 120
Field strength – dB µ
10
-10
10
2
3
5
7 100
2
3
5
7 1k
10
S(80 dBµ)
S (40 dBµ)
-40
-50
-60
40
5
0
7 10k
S (80 dBµ)
0
S (60 dBµ)
-20
-30
3
AM Two-Signal Interference Suppression
Characteristics (∆ 400 kHz)
S(40 dBµ)
-10
2
Frequency, fm – Hz
AM Two-Signal Interference Suppression
Characteristics (∆ 40 kHz)
0
S-meter voltage, Vsm – V
Output – dB
9
Total harmonic distortion, THD – %
0
8
Total harmonic distortion, THD – %
S-meter voltage, Vsm – V
Total harmonic distortion, THD – %
S-meter voltage, Vsm – V
10
S(60 dBµ)
-10
-20
N (40 dBµ)
-30
N(60 dBµ)
-40
N (60 dBµ)
N (60 dBµ)
-50
N (80 dBµ)
N (80 dBµ)
60
N(40 dBµ)
80
100
fu input level – dBµ
120
140
-60
40
N(60 dBµ)
N(80 dBµ)
N(80 dBµ)
60
80
100
120
140
fud input level – dBµ
No.8085-36/41
LA1776M
FM Temperature Characteristics
FM Temperature Characteristics
400
80
output
S/N
70
S/N, AMR – dB
Output – mV rms
350
300
250
60
AMR (80 dB)
AMR (50 dB)
50
200
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
40
-40
90
-30 -20 -10
Ambient temperature, Ta – ºC
Q.S., U.S., Noise convergence – dBµ, dB
–3dB L.S – dB
15
10
n)
o
ute
B (m
–3d
–3dB (mute off)
0
-5
-40
-30 -20
-10
0
10
20
30
40
50
60
70
80
90
50
60
70
80
90
80
90
80
90
80
90
Q.S (S/N = 50)
Noise convergence
20
10
U.S (S/N = 30)
0
-40 -30 -20 -10
0
10
20
30
40
50
60
70
FM Temperature Characteristics
50
W-AGC
40
Separation, Sep – dB
N-AGC, W-AGC on level – dBµ
40
30
FM Temperature Characteristics
80
70
N-AGC
50
-40 -30 -20 -10
0
10
SEP (80 dBµ)
30
20
SEP (35 dBµ)
10
20
30
40
50
60
70
80
0
-40 -30 -20 -10
90
Ambient temperature, Ta – ºC
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
FM Temperature Characteristics
FM Temperature Characteristics
3
3
2.9
fc
Va
2
Vafc,Vref – V
Total harmonic distortion, THD – %
30
Ambient temperature, Ta – ºC
100
60
20
40
Ambient temperature, Ta – ºC
90
10
FM Temperature Characteristics
FM Temperature Characteristics
20
5
0
Ambient temperature, Ta – ºC
1
2.8
2.7
Vref
2.6
THD (mono)
2.5
THD (main)
0
-40 -30 -20 -10
0
10
20
30
40
50
60
Ambient temperature, Ta – ºC
70
80
90
2.4
-40 -30 -20 -10
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
No.8085-37/41
LA1776M
FM Temperature Characteristics
FM Temperature Characteristics
0.5
130
0.4
120
SD bandwidth – kHz
0.3
Vnull – V
0.2
0.1
Vnull
0
-0.1
-0.2
110
SD bandwidth
100
90
-0.3
-0.4
-0.5
-40 -30 -20 -10
10
0
20
30
40
50
60
70
80
80
-40 -30 -20 -10
90
Ambient temperature, Ta – ºC
10
40
30
50
60
70
80
90
80
90
80
90
80
90
40
SD bandwidth (+)
60
40
SD on level – dBµ
35
20
0
-20
-40
30
25
SD bandwidth (–)
-80
-40 -30 -20 -10
10
0
20
30
40
50
el
n lev
SD o
-60
60
70
80
20
-40 -30 -20 -10
90
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
Ambient temperature, Ta – ºC
FM Temperature Characteristics
FM Temperature Characteristics
6
70
Vsm (80 dBµ)
5
S-meter voltage, Vsm – V
Signal-to-noise ratio with IF beating – dB
20
FM Temperature Characteristics
FM Temperature Characteristics
80
SD bandwidth – kHz
0
Ambient temperature, Ta – ºC
60
96.3 MHz beating worst case
50
Hz
M
107
40
-40 -30 -20 -10
0
be
atin
t
ors
gw
cas
e
Vsm (70 dBµ)
4
Vsm (60 dBµ)
3
Vsm (50 dBµ)
Vsm (40 dBµ)
2
Vsm (30 dBµ)
1
10
20
30
40
50
60
70
80
0
-40 -30 -20 -10
90
Ambient temperature, Ta – ºC
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
FM Temperature Characteristics
FM Temperature Characteristics
400
80
S/N
output
350
AMR (60 dBµ)
S/N, AMR – dB
output – mVrms
70
300
60
50
250
40
200
-40 -30 -20 -10
0
10
20
30
40
50
60
Ambient temperature, Ta – ºC
70
80
90
30
-40 -30 -20 -10
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
No.8085-38/41
LA1776M
FM Temperature Characteristics
FM Temperature Characteristics
80
60
70
50
–3 dB L.S – dBµ
ST S/N – dB
ST S/N (15 kHz)
60
ST S/N (OFF)
50
40
–3 dB (mute on)
30
40
30
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
20
-40
90
Ambient temperature, Ta – ºC
-10
0
10
20
30
40
50
60
70
80
90
80
90
80
90
FM Temperature Characteristics
90
60
85
55
SD on LEVEL – dBµ
N-AGC on LEVEL – dBµ
-20
Ambient temperature, Ta – ºC
FM Temperature Characteristics
N-AGC on
80
50
vel
SD on le
45
75
70
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
40
-40 -30 -20 -10
90
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
Ambient temperature, Ta – ºC
FM Temperature Characteristics
FM Temperature Characteristics
6
IF count BUFF LEVEL – mVrms
3
Total harmonic distortion, THD – %
-30
2
1
THD (mono)
5
4
3
IF co
uff
unt b
2
1
THD (main)
0
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
90
Ambient temperature, Ta – ºC
0
-40 -30 -20 -10
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
FM Temperature Characteristics
6
Vsm (90
0 dBµ)
S-meter voltage, Vsm – V
Vsm (8
dBµ)
0 dBµ)
Vsm (7
4
0 dBµ)
Vsm (6
Vsm (50 dBµ)
Vsm (40 dBµ)
2
Vsm (30 dBµ)
0
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
90
Ambient temperature, Ta – ºC
No.8085-39/41
LA1776M
AM Temperature Characteristics
AM Temperature Characteristics
40
60
Practical sensitivity – dBµ, SD on – dBµ
S/N, AGC FOM – dB
70
S/N
AG
CF
OM
50
40
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
35
25
0
10
20
30
40
50
60
70
80
90
80
90
80
90
Ambient temperature, Ta – ºC
AM Temperature Characteristics
AM Temperature Characteristics
60
Vsm (74 dBµ)
N-AGC, W-AGC on LEVEL – dBµ
Vsm (130 dBµ)
5
4
Vsm – V
it
ensitiv
ical s
t
c
a
r
P
20
-40 -30 -20 -10
90
6
3
Vsm (30 dBµ)
2
1
Vsm (–20
W-AGC
55
W-AGC (SEEK)
50
N-AGC
45
dBµ)
0
-40 -30 -20 -10
0
10
20
30
40
50
60
70
80
40
-40 -30 -20 -10
90
Ambient temperature, Ta – ºC
4
-1
AM LC (100 Hz) – dB
0
3
THD (0.1 k, 80 %)
2
D
(1
k,
8
THD (0.1 k, 30 %)
0%
10
20
30
40
50
60
70
AM Temperature Characteristics
5
TH
0
Ambient temperature, Ta – ºC
AM Temperature Characteristics
Total harmonic distortion, THD – %
y
30
Ambient temperature, Ta – ºC
1
SD
-2
-3
100 Hz attenuation
-4
)
0
-40 -30 -20 -10
THD (1 k, 30 %)
0
10
20
30
40
50
60
Ambient temperature, Ta – ºC
70
80
90
-5
-40 -30 -20 -10
0
10
20
30
40
50
60
70
Ambient temperature, Ta – ºC
No.8085-40/41
LA1776M
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 expor ted without obtaining the expor t 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 July, 2005. Specifications and information herein are subject
to change without notice.
PS No.8085-41/41