LA1780 [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： | LA1780 |
| 厂家： | 
SANYO SEMICON DEVICE |
| 描述： | Single-Chip Tuner IC for Car Radios |
| 文件： | 总38页 (文件大小：759K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Ordering number : ENN5724A
Monolithic Linear IC
LA1780M
Single-Chip Tuner IC for Car Radios
— Superlative listenability due to improved medium and
weak field noise canceller characteristics.
— Improved separation characteristics
— Anti-birdie filter
— Improved AM and FM thermal characteristics
— Excellent FM signal meter linearity
— 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).
Overview
The LA1780M integrates all six blocks required in a car
radio tuner on a single chip. The LA1780M is based on
the LA1888NM, and features improvements to each of the
blocks; improvements designed to provide improved noise
characteristics, especially for noise related to multipath,
three-signal intermodulation distortion, and two-signal
suppression.
Functions
• FM front end
• FM IF
• Noise canceller
• Multiplex
• AM up-conversion
• FM/AM switch
• MRC
• 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.)
• Since the LA1780M retains the block structure of the
LA1888NM, products using that IC can be easily
converted, allowing further end product miniaturization.
Features
• Improved noise reduction methods
— The FM front end provides excellent 3-signal
characteristics equivalent to those of the LA1193M.
Package Dimensions
Unit:mm
3159-QFP64E
[LA1780M]
17.2
3
Mounted on a 40 × 80 × 1.3 mm
1.6
1.0
14.0
0.35
glass epoxy printed circuit board
1.0
48
0.8
0.15
33
Independent IC
32
49
17
64
1
16
0.1
2.7
15.6
0.8
Ambient temperature, Ta — °C
SANYO: QFP64E (QIP64E)
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
33100TN (OT)/92498RM (OT) No. 5724-1/38
LA1780M
Specifications
Maximum Ratings at Ta = 25°C
Parameter
Symbol
VCC1 max
VCC2 max
Pd max
Topr
Conditions
Ratings
Unit
V
Pins 6, 40, and 61
9
12
Maximum supply voltage
Pins 7, 45, 54, 59, and 60
V
Allowable power dissipation
Operating temperature
Storage temperature
Ta ≤ 55°C
950
mW
°C
°C
–40 to +85
Tstg
–40 to +150
Operating Conditions at Ta = 25°C
Parameter
Symbol
VCC
Conditions
Pins 6, 7, 40, 45, 54, 59, 60, and 61
Ratings
Unit
V
8
5
Recommended supply voltage
Operating supply voltage range
VCCST IND Pin 26
VCC op
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
ICCO-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
VO-FM31
CB
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
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
1.2
0.6
2.4
1.6
0.3
4.4
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
VSM FM-1
VSM FM-2
VSM FM-3
VSM FM-4
BW-mute
54
220
0.0
62
330
0.1
70
440
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
V
0.4
1.0
1.5
Signal meter output
2.0
2.7
3.5
V
4.7
5.5
6.2
V
Muting bandwidth
Mute drive output
100
0.00
150
0.03
200
0.20
kHz
V
VMUTE-100
Continued on next page.
No. 5724-2/38
LA1780M
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
80
87
94
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
100
106
112
Conversion gain
A.V
83 MHz, 80 dBµ, unmodulated. The FE CF output
No input
19
30
48
mVrms
mVrms
Oscillator buffer output
[NC Block] NC input (pin 30)
Gate time
VOSCBUFFFM
260
370
480
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
85
75
dB
Detector output
120
110
170
150
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
56
47
61
66
dB
Signal-to-noise ratio
S/N-AM
THD-AM
VSM AM-1
VSM AM-2
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
4.8
230
89
dB
%
Total harmonic distortion
1
0.0
3.8
185
83
0.5
6.2
V
Signal meter output
1 MHz, 130 dBµ, unmodulated
V
Oscillator buffer output
Wide band AGC sensitivity
VOSCBUFF AM1 No input, the pin 5 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
95
86
38
38
1.4 MHz, the input when V46 = 0.7 V (seek mode)
74
80
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
26
32
SD sensitivity
26
32
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. 5724-3/38
LA1780M
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
VO-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
b
—
VO-FM31
CB
ON
b
—
ON
b
—
Total harmonic distortion
Signal-to-noise ratio: IF
AM suppression ratio: IF
Muting attenuation 1
Muting attenuation 2
Muting attenuation 3
Separation
THD-FMmono
S/N-FM IF
AMR IF
ON
b
—
ON
b
—
ON
b
—
Att-1
ON
b
—
Att-2
ON
b
—
Att-3
ON
b
—
Separation
ST-ON
ON
b
—
Stereo on level
ON
b
—
Stereo off level
ST-OFF
ON
b
—
Main total harmonic distortion
Pilot cancellation
THD-Main L
PCAN
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
VSM FM-1
VSM FM-2
VSM FM-3
VSM FM-4
BW-mute
VMUTE-100
VNAGC
ON
b
OFF
ON
OFF
—
SD sensitivity 2
ON
b
IF counter buffer output
Signal meter output 1
Signal meter output 2
Signal meter output 3
Signal meter output 4
Muting bandwidth
ON
b
ON
b
ON
b
—
ON
b
—
ON
b
—
ON
b
—
Mute drive output
ON
b
—
N-AGC on input
ON
a
—
W-AGC on input
VWAGC
ON
a
ON
—
—
Conversion gain
A.V
ON
a
ON
—
—
Oscillator buffer output
Gate time 1
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
ON
—
—
NC effect
SN-NC
ON/OFF
ON
—
—
MRC output
VMRC
—
—
MRC operating level
Practical sensitivity
Detection output
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
—
—
—
Pin 31 detection output
AGC F.O.M.
VO-AM31
VAGC-FOM
S/N-AM
—
—
—
—
—
—
Signal-to-noise ratio
Total harmonic distortion
Signal meter output 1
Signal meter output 2
Oscillator buffer output
Wide band AGC sensitivity 1
Wide band AGC sensitivity 2
SD sensitivity 1
—
—
—
THD-AM
VSM AM-1
VSM AM-2
VOSCBUFF AM-1
W-AGCsen 1
W-AGCsen 2
SD-sen1 AM
SD-sen2 AM
VIFBUFF-AM
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
SD sensitivity 2
—
—
—
IF buffer output
—
—
—
No. 5724-4/38
LA1780M
Block Diagram
IF limiter
amplifier
No. 5724-5/38
LA1780M
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. 5724-6/38
LA1780M
Pin Descriptions
Pin No.
Function
Description
Equivalent circuit
62 pin
An antenna damping current flows
when the RF AGC voltage (pin 2)
reaches VCC-VD.
1
Antenna damping drive
Used to control the FET
second gate.
2
RF AGC
3
F.E.GND
Oscillator connection
The transistor and capacitors
required for the oscillator circuit
are integrated on the chip.
4
OSC
AM first oscillator
This circuit can oscillator up to the
SW band.
7
AM OSC
An ALC circuit is included.
Continued on next page.
No. 5724-7/38
LA1780M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
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)
8
9
Noise AGC sensitivity
AGC adjustment
11
12
Memory circuit connection
Memory circuit connection
Recording circuit used during
noise canceller operation.
Differential
amp
Gate
circuit
13
Pilot input
Pin 13 is the PLL circuit input pin.
Ground for the N.C., MPX, and
MRC circuits.
14
N.C, MPX, MRC, GND
Continued on next page.
No. 5724-8/38
LA1780M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
Deemphasis
50 µs: 0.015 µF
75 µs: 0.022 µF
15
16
MPX output (left)
MPX output (right)
Adjustment is required since the
pilot signal level varies with the
sample-to-sample variations in
the IF output level and other
parameters.
17
Pilot canceller signal output
Pin 18 is the output pin for the
pilot canceller signal.
18
Pilot canceller signal output
Continued on next page.
No. 5724-9/38
LA1780M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
Composite
signal
Use a trimmer to adjust the
subdecoder input level.
(The output level is not modified in
mono and main modes.)
Separation
adjustment pin
19
20
VCO
The oscillator frequency is 912 Hz.
KBR-912F108
(Kyocera Corporation)
CSB-912JF108
(Murata Mfg. Co., Ltd.)
21
22
PHASE COMP.
PHASE COMP.
Continued on next page.
No. 5724-10/38
LA1780M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
IF counter
buffer
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.
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
(two modes: 0 and 5 V)
5 V: Seek mode
0 V: Reception mode
Forced
SD: 2.5 V
FM
S-meter
24
32
AM/FM signal meter
Fixed-current drive signal meter
output
AM
S-meter
In AM mode, pin 32 outputs a
1-mA current. Thus the HCC
circuit is turned off.
Dedicated FM signal meter
Outputs a 1-mA
current during AM
reception
FM reception: the voltage V23
switches between three modes
as follows.
Stereo
indicator
5 V: The SD pin operates linked
to the IF counter buffer.
2.5 V: Forced SD mode: operates
as the SD pin.
0 V: Reception mode: stereo
indicator
26
Stereo indicator for the SD pin
Seek/stop
switching
AM reception: (two modes: 0 and 5 V)
5 V: Operates as the seek SD pin.
0 V: Reception mode. Not used.
Continued on next page.
No. 5724-11/38
LA1780M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
The MRC detector time constant
is determined by a 1-kΩ resistor
and C2 when discharging and by
the 7-µA current and C2 when
charging.
27
MRC control voltage time
constant
Pin 28
The sub-output is controlled by a
0 to 1-V input.
28
SNC control input
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.
MRC input
Continued on next page.
No. 5724-12/38
LA1780M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
FM
detector
output
Pin 30 is the noise canceller input.
The input impedance is 50 kΩ.
30
31
Noise canceller input
AM/FM detector output
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.
AM
detector
Noise
canceller
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.
32
IF S-meter output and MRC
DC input
MRC input
•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
•Noise convergence adjustment
The noise convergence can be
adjusted when there is no input
signal by inserting a resistor
between pin 33 and ground.
33
Mute drive output
Band
muting
•Muting off function
Ground pin 33 through a 4-kΩ
resistor.
SD circuit
Continued on next page.
No. 5724-13/38
LA1780M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
•The resistor R1 determines the
width of the band muting function.
Increasing the value of R1
narrows the band.
Quadrature
detector
Reducing the value of R1 widens
the band.
34
35
36
37
AGC
QD output
QD input
VREF
•Null voltage
When tuned, the voltage between
pins 34 and 37, V
, will be 0 V.
34 – 37
The band muting function turns
on when |V34 – 37| ≥ 0.7 V.
V
37 = 4.9 V
IF limiter amplifier
Band
muting
A 130-µA current flows from pin
38 and, in conjunction with the
external resistance R, determines
the comparison voltage.
38
FM SD ADJ
Comparator
S-meter
S-meter
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
39
Keyed AGC
AM stereo buffer
between pin 39 and ground.
This pin also is used as the AM
stereo IF buffer pin.
Continued on next page.
No. 5724-14/38
LA1780M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
The HCC frequency characteristics
are determined by the external
capacitor connected at this pin.
41
HCC capacitor
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.
Note: The LC capacitor must be
connected between this pin
and VCC (pin 40).
42
AM L.C. pin
This is because the detector
circuit operates referenced
to VCC
.
The cutoff frequency fC is
determined by the following
formula.
fC = 1/2π × 50 k × C
Inserting a 1-MΩ resistor between
pin 43 and VCC will force the IC
to mono mode.
43
Pilot detector
Continued on next page.
No. 5724-15/38
LA1780M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
Q1: Used for time constant
switching during seeks.
τ = 2.2 µF × 300 k
• Seek
44
IF AGC
τ = 2.2 µ × 10
The external capacitors are
connected to VCC
This is because the IF amplifier
operates referenced to VCC
.
.
Pin 40 VCC
Pin 40 VCC
45
IF output
The IF amplifier load
AM antenna damping
drive output
Wide band AGC input
I46 = 6 mA (maximum)
This is the antenna damping
current.
46
Continued on next page.
No. 5724-16/38
LA1780M
Continued from preceding page.
Pin No. Function
Description
Equivalent circuit
Modify the value of the external
resistor to adjust the muting on
level.
FM muting on level
adjustment
47
Inverter
Pin 24
RF AGC rectification capacitor
The low frequency distortion is
determined as follows:
Increasing C48 and C57 improves
the distortion but makes the
response slower.
Antenna
damping
48
57
RF AGC bypass
RF AGC
Reducing C48 and C57
aggravates the distortion but
makes the response faster.
For AGC
use
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
51
IF bypass
FM IF input
52
IF input
The input impedance is 2 kΩ.
Continued on next page.
No. 5724-17/38
LA1780M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
• Input and output pin or the first
IF amplifier
• Inverting amplifier
53
56
IF amplifier output
IF amplifier input
V56 = 2 V
Input impedance: RIN = 330 Ω
V53 = 5.3 V
Output impedance
ROUT = 330 Ω
Pin 40 VCC
Pin 40 VCC
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
Pin 62
VCC
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.
55
58
W-AGC IN
AM SD ADJ
Pin 55 functions as the SD
sensitivity adjustment pin in
AM mode.
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.
Signal meter
Continued on next page.
No. 5724-18/38
LA1780M
Continued from preceding page.
Pin No.
Function
Description
Equivalent circuit
Double balanced mixer
Pins 60 and 61 are the mixer
10.7-MHz output
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.
59
60
63
64
Mixer output
Mixer input
Note:The lines for pins 63 and 64
must be kept separated from
the lines for pins 60 and 61.
Pin 62 functions both as the FM
front end VCC and the AM/FM
switching circuit.
AM/FM
switching circuit
6
Front end VCC AM/FM
switching
V6 voltage
When 8 V → FM
OPEN → AM
Mode
To RF
Amp.
First mixer input
The input impedance is about
10 kΩ.
1st MIX
INPUT
62
To 2nd
MIX
Crystal oscillator circuit
10
AM 2nd OSC
The Kinseki, Ltd. HC-49/U-S and
a CL of 20 pF must be used.
Continued on next page.
No. 5724-19/38
LA1780M
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
VCC for the FM front end, AM first mixer, and first oscillator blocks
VCC 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
CC
potential 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
4. Relationship between Pin 23 and Pin 26
• FM mode
Pin 26 functions as both the stereo indicator and the SD pin.
Pin 23: DC-input seek/stop pin (control pin)
AC output IF counter buffer pin
IF counter buffer
Between 0 and a few
thousand Ohms.
The Pin 23 Control Function and the Relationship between Pin 23 and Pin 26
SW1
OPEN
ON
SW2
OPEN
OPEN
ON
Pin 23 voltage
5 V
Pin 26
IF counter buffer on
OFF
Pin 26
SD
2.5 V
High-speed SD
Stereo indicator
—
Under 0.7 V
OFF
No. 5724-20/38
LA1780M
S-meter
Larger
R38
Smaller R38
V33
0.7 V or
over
V33
0.7 V or
over
On and
function-
ing as
Stereo
Mono
SD
IF
counter
buffer
on
IF counter output off
Used as RDS and similar function
SD detection by switching this mode.
Notes on FM SD
Band
muting
Mute drive
output
S-meter
IF counter buffer
IF counter output
No. 5724-21/38
LA1780M
• AM mode
S-meter
Larger
R55
Smaller R35
Pin 55: AM SD Adjustment Pin
• Pins that support AM stereo
To an AM
stereo decoder
400-mV rms
450-kHz output
Keyed
AGC
• To attenuate the pin 39 AC level:
Add a capacitor between pin 39 and ground.
For example, if a capacitor is added between pin 39 and ground, and pin 51 is attached, the AM IF output will be
reduced by about 6 dB.
No. 5724-22/38
LA1780M
• Notes on the muting attenuation
The resistor between pin 58 and ground switches the muting attenuation to one of three levels, –20, –30, and –40 dB.
This is also related to the tuner’s total gain.
R
Mute ATT
–20 dB
–30 dB
–40 dB
OPEN
200k
30k
If R33 is reduced, the attenuation will be
reduced as listed in the table above.
Muting time constants
Attack: 10 k × C33
Release: 50 k × C33
Quadrature detector
Limiter
No. 5724-23/38
LA1780M
• MRC circuit
FM
S-meter
S-meter
Noise amplifier
fc = The MPF + AMP 70 kHz
Required external transistor: 2SC536 or equivalent
Reason: Since the LA1780M MRC is a simplified
circuit, an OMRC level shifter is required.
To SNC
Pin 28
• If there is no AC noise on pin 32:
V24 = V27 – V
BE
↑
Q
MRC
V27 will be about 2.5 V for an antenna input of 60 dBµ or higher.
• Since the MRC noise amplifier gain is fixed, the MRC circuit is adjusted by reducing the AC input level.
• The MRC circuit attack and release times are determined by the capacitor C27 on pin 27.
Attack: 7 µA × C27
Release: 500 Ω × C27
5. FM Soft Muting
Smaller R47
Larger R47
Larger
R47
Smaller R47
By comparing the pin 47 mute on adjustment voltage to the S-meter voltage (V24), the muting on point can be adjusted.
No. 5724-24/38
LA1780M
• Noise canceller notes
The characteristics of the noise canceller have been
improved by implementing the circuit that determines the
gate time in logic. In earlier noise canceller circuits, since
the time constant was determined with an RC circuit such
as the one shown in figure 5, the rise time was influenced
by the RC circuit time constant as show in figure 6. This
meant that the rise was delayed and the associated
switching delay resulted in a reduction of the circuit’s
ability to exclude noise.
Figure 5
In the LA1780M, the rise time is made shorter by
implementing the circuit that determines the gate time in
logic. This allows the LA1780M to eliminate noise
reliably.
Figure 6
• Gain distribution (FM)
This section analyzes the gain in each of the blocks in the LA1780M when the Sanyo recommended circuit is used.
Test conditions
Ambient temperature:
26°C
Antenna and mixer input frequency: 98.1 MHz
First and second IF input frequency: 10.7 MHz
Input levels when VSM = 2 V were measured to be:
Antenna input: 19 dBµ
Mixer input:
30 dBµ
First IF input: 42 dBµ
Second IF input:60 dBµ
These values allow the gains in each block to be calculated as follows.
RF gain:
11 dB
Mixer gain: 12 dB
No. 5724-25/38
LA1780M
AM
This section analyzes the gain in each of the blocks in the LA1780 when the Sanyo recommended circuit is used.
Test conditions
Ambient temperature:
26°C
Antenna and mixer 1 input frequency: 1 MHz
Mixer 2 input frequency:
IF and detector input frequencies:
An AM dummy is attached.
10.71 MHz
450 kHz
When an input level such that the output becomes –35 dBm is determined, the I/O characteristics of each stage were
determined to be as follows:
Antenna input: 9.5 dBµ
Mixer 1 input: 25.6 dBµ
Mixer 2 input: 29.5 dBµ
IF input:
36.0 dBµ
Detector input: 102.0 dBµ
These values allow the gains in each block to be calculated as follows.
RF gain:
16.1 dB
Mixer 1 gain: 3.9 dB
Mixer 2 gain: 6.5 dB
IF gain:
66.0 dB
No. 5724-26/38
LA1780M
• Input circuits used at each stage
[FM]
Mixer input
First IF input
Actual
measurement
IF input
[AM]
First mixer input
Second mixer input
IF input
Detector input
No. 5724-27/38
LA1780M
• 3D AGC (keyed AGC) settings
S-meter
VS-meter
· The antenna damping function operates by providing the pin diode antenna damping current from the pin when the
pin 2 voltage becomes equal to V – V
.
BE
CC
· The noise AGC circuit operates as follows:
When the pin 39 voltage is greater than (6.4/3.6) times the pin 24 voltage, the ACG circuit is off.
When the pin 39 voltage is less than (6.4/3.6) times the pin 24 voltage, the ACG circuit is on.
No. 5724-28/38
LA1780M
AM AGC System
The LA1780M RF AGC is picked up from three locations.
· The wide AGC determined by Rw
· The middle AGC picked up from the pin 49 second mixer input
The operating bandwidth is 150 kHz to 180 kHz (the bandwidth of the 10.7 MHz CF)
· The narrow AGC picked up from pin 52
The operating bandwidth is 7 kHz (the bandwidth of the 450 kHz CF)
AM AGC Frequency Characteristics
Wide AGC
Wide AGC
Operates for wide-band
interfering stations.
Operates for wide-band
interfering stations.
Middle AGC
Middle AGC
Operates for interfering
stations that are
±70 kHz from the
received frequency.
Operates for interfering
stations that are ±70
kHz from the received
frequency.
Narrow AGC
Operates at the
received frequency.
Frequency, — Hz
No. 5724-29/38
LA1780M
• Sample AM application using the LC72144 and the LA1780M
AM 1st IF
Step
FM IF
1
2
fOSC 10.25 MHz
fOSC 10.35 MHz
10.7 MHz
10.8 MHz
10 K, 1 K
9 K, 10 K
10.7 MHz
10.8 MHz
No. 5724-30/38
LA1780M
Crystal Oscillator Element (Kinseki, Ltd.)
HC-49/U-S
Frequency: 10.26 MHz
Load capacitance: 20 pF
Equivalent series resistance: 90 Ω
Coil Specifications (SUMIDA ELECTRIC CO., LTD.)
Application:
Prototype number
[AM Block]
Model number
AM FILTER
AM OSC
SA-1051
SA-359
Y-5G (For the first mixer input: 5 mm diagonal)
S-7LB
AM IF1 (MIX)
SA-264
PG78
SA-1111
SA-1009
SA-1063
SA-1112
SA-265
PG57 (5 mm, high reliability)
P-5DJ (5 mm diagonal)
PG78
PG57 (5 mm, high reliability)
P-5DJ (5 mm diagonal)
MG78
AM IF2
AM loading
SA-1062
AM antenna input SA-1048
MG78
AM RF amplifier
[FM Block]
FM RF
FM ANT
FM OSC
RC875-222J
RC875
SA-1060
SA-1061
SA-1052
SA-266
SA-208
SA-360
S-7LDJ
S-7LDJ
S-7LDJ
FM MIX
FM DET
P-7LFJ (Double balanced mixer)
QU-7L (Quadrature detector)
QU57 (5 mm diagonal, quadrature detector)
AM Block
• SA-359 (AM FILTER)
• SA-264 (AM IF1)
① – ② 30T
⑥– ④ 19T
② – ③151T
0.05 UEW
① – ② 16T
② – ③16T
0.08 UEW
• SA-1063 (AM IF2)
• SA-1062 (AM loading)
① – ② 75T
② – ③75T
0.05 UEW
① – ③850T
0.05 UEW
• SA-1048 (AM ANT IN)
① – ③74T
0.07 UEW
No. 5724-31/38
LA1780M
FM Block
• SA-1060 (FM RF)
• SA-1061 (FM ANT)
⑥– ④ 1T
0.10 UEW
③– ① 3T
③– ① 3T
0.16 UEW
⑥– ④ 3T
⑥– ④ 3T
0.16 UEW
• SA-1052 (FM OSC)
• SA-266 (FM MIX)
③– ① 3T
1
⑥– ② 6
2
1
② – ④ 6
2
⑥– ① 2T
⑥– ① 2T
0.18 UEW
T
T
0.10 UEW
• SA-208 (FM DET)
1
4
④ – ③18
T
T
0.08 UEW
1
4
③– ① 70
0.06 UEW
Coil Specifications (Toko INC)
[AM Block]
AM ANT
ANT
Toko Part No.
269ANS-0720
385BNS-027Z
187LY-222K
Choke
MIX LPF
AM 2nd MIX
AM OSC
AM IFT2
[FM Block]
AM, FM, MIX
FM DET
FM ANT
FM RF
A286LBIS-15327
L7TCS-3039A
V666SNS-213BY
7PSG-5002
3710H-1108FYH
DM600DEAS-8407
666SNS-219NK
666SNS-218AQ
V666SNS-205APZ
FM OSC
No. 5724-32/38
LA1780M
FM Block
• 3710H-1108FYH (AM • FM • MIX)
• DM600DEAS-8407GLF (FM DET)
③– ① 13T
1
2
⑥– ③19
T
1
③– ⑤ 6
⑤ – ① 6
T
2
1
2
1
⑥– ④ 2
T
2
T
③– ① 59T
0.07ø ZUEW
⑥– ④ 2T
0.07ø ZUEW
• 666SNS-219NK (FM ANT)
• 666SNS-218AQ (FM RF)
1
2
1
2
③– ① 2
T
④ – ⑥2
T
⑥– ④ 1T
0.1ø ZUEW
0.1ø ZUEW
• V666SNS 205APZ (FM OSC)
⑥– ① 2
0.12ø ZUEW
AM Block
• 269ANS-072Z (AM ANT)
• 385BNS-027Z (ANT)
① – ③60T
0.06 3UEW
① – ③60T
0.06ø 3UEW
• 187LY-222K (Choke)
• A286LBIS-15327 (MIX LPF)
243
0.1ø ZUEW
No. 5724-33/38
LA1780M
• L7TCS-3039A (AM 2nd MIX)
① – ③152T
• V666SNS-213BY (AM OSC)
③– ① 24
1
2
1
4
1
4
T
T
T
① – ② 25T
② – ③127T
⑥– ④ 16T
0.05ø 3UEW
③– ② 12
② – ① 12
0.1ø ZUEW
• 7PSG-500Z (AM IFTZ)
① – ③148T
① – ② 74T
② – ③74T
0.05ø 3UEW
No. 5724-34/38
LA1780M
FM I/O Characteristics
FM I/O Characteristics
Antenna input, — dBµ
Antenna input, — dBµ
FM Distortion
FM Sensitivity Suppression
Antenna input, — dBµ
Antenna input, — dBµ
FM Gain Distribution (1)
FM Gain Distribution (2)
Input, — dBµ
Input, — dBµ
Mixer I/O Characteristics
First IF I/O Characteristics
Mixer input, — dBµ
First IF input, — dBµ
No. 5724-35/38
LA1780M
First IF Frequency Characteristics.
AM I/O Characteristics
Frequency, — MHz
Antenna input, — dBµ
AM Distortion
AM DC Characteristics
Antenna input, — dBµ
Antenna input, — dBµ
FM Antenna Input Temperature Characteristics (1)
FM Antenna Input Temperature Characteristics (2)
Separation
Ambient temperature, Ta — °C
Ambient temperature, Ta — °C
FM Antenna Input Temperature Characteristics (3)
FM Antenna Input Temperature Characteristics (4)
Ambient temperature, Ta — °C
Ambient temperature, Ta — °C
No. 5724-36/38
LA1780M
FM Antenna Input Temperature Characteristics (5)
FM Antenna Input Temperature Characteristics (6)
Ambient temperature, Ta — °C
Ambient temperature, Ta — °C
AM Antenna Input Temperature Characteristics (1)
AM Antenna Input Temperature Characteristics (2)
Ambient temperature, Ta — °C
Ambient temperature, Ta — °C
AM Antenna Input Temperature Characteristics (3)
FM Soft Muting (1)
Ambient temperature, Ta — °C
Antenna input, — dBµ
FM Soft Muting (2)
FM Soft Muting (3)
Antenna input, — dBµ
Antenna input, — dBµ
No. 5724-37/38
LA1780M
AM AGC Frequency Characteristics
AM AGC Frequency Characteristics
With a 10-pF capacitor
connected to pin 58
Frequency, — MHz
Frequency, — Hz
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 March, 2000. Specifications and information herein are subject to
change without notice.
PS No. 5724-38/38
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