Ordering number : ENN*7931
LA1845NV
Monolithic Linear IC
Single-Chip Home Stereo IC
The LA1845NV is designed for use in mini systems and is a single-chip tuner IC that provides electronic tuning
functions using SD/IF-count technique. It incorporates a pilot canceler and an adjustment-free MUX VCO circuit,
thus allows additional parts to be reduced.
Functions
•
AM
: RF amplifier, mixer, oscillator, IF amplifier, detector, AGC, SD, oscillator buffer, IF buffer, stereo IF output,
AGC time constant switch
•
FM IF : IF amplifier, quadrature detector, S-meter, SD (signal detection), S-curve detection, IF buffer output
•
MPX : PLL stereo decoder, stereo display, forced monaural, VCO stop, audio muting, adjacent channel interference
rejection function, pilot canceler
Features
•
Integrated MPX VCO (ceramic resonators are no longer required.)
•
Built-in adjacent channel interference rejection function (114kHz, 190kHz)
•
Supports both SD and IF-count techniques
•
Both FM SD sensitivity and bandwidth can be set
•
Pilot canceler built in.
Maximum Ratings
at Ta = 25°C
Parameter
Maximum Power Supply Voltage
Allowable Power Consumption
Symbol
VCC max
Pd max
Ta = 80°C with board
114.3mm×76.1mm×1.6mm material :
Glass epoxy resin
Operating Temperature
Storage Temperature
Topr
Tstg
-20 to +80
-40 to +125
°C
°C
360
mW
Conditions
Ratings
6
Unit
V
Operating Conditions
at Ta = 25°C
Parameter
Recommended Supply Voltage
Operating Supply Voltage Range
Symbol
VCC
VCC op
Ta = 80°C
Conditions
Ratings
5
4.3 to 5.5
Unit
V
V
Any and all SANYO Semiconductor 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 Semiconductor representative
nearest you before using any SANYO Semiconductor products described or contained herein in such
applications.
SANYO Semiconductor 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 Semiconductor
products described or contained herein.
92706 / 91004 JO IM No.7931-1/10
LA1845NV
Electrical Characteristics
•
Operating Characteristics
at VCC = 8V, in the specified test circuit.
FM Mono Characteristics
at fc = 10.7MHz, Vi = 100dBµ, fm = 1kHz, Modulation = 75kHz
Parameter
Current Drain
Demodulator Output
Total Harmonic Distortion
Signal-to-Noise Ratio
AM Rejection Ratio
3dB Sensitivity
SD Sensitivity
IF Counter Buffer Output
Mute Attenuation
With no input signal
100dBµ, 100% modulation, fm = 1kHz
100dBµ, 100% modulation, fm = 1kHz
100dBµ, 100% modulation, fm = 1kHz
100dBµ, AM = 30% modulation, fm = 1kHz
100dBµ, 100% modulation, fm = 1kHz Output reference,
-3dB input
0% modulation
100dBµ
100dBµ, 100% modulation, fm = 1kHz
38
200
73
47
Conditions
Ratings
min
20
230
typ
30
360
0.35
80
65
32
47
275
76
40
56
400
max
40
460
1.5
Unit
mA
mVrms
%
dB
dB
dBµ
dBµ
mVrms
dB
FM Stereo Characteristics
at fc = 10.7MHz, Vi = 100dBµ, L+R = 90%, Pilot = 10%, fm = 1kHz
Parameter
Separation
Stereo On Level
Total Harmonic Distortion
Adjacent Channel Rejection Ratio 1
Adjacent Channel Rejection Ratio 2
Carrier Leak
Conditions
L+R = 90%, Pilot = 10%, fm = 1kHz
Pilot input
Pilot input
fs = 113kHz, VS = 90%, Pilot = 10% ;
The left-right modulation, demodulated output
fs = 189kHz, VS = 90%, Pilot = 10% ;
The left-right modulation, demodulated output
L+R = 90%, Pilot = 10% reference, Pilot = 10% output
38
Ratings
min
30
1.5
typ
42
3.5
0.45
36
41
44
5.5
1.5
max
Unit
dB
%
%
dB
dB
dB
AM Characteristics
at fc = 1000kHz, Vi = 80dBµ, fm = 1kHz, Modulation = 30%
Parameter
Current Drain
Detector Output 1
Detector Output 2
Signal-to-Noise Ratio 1
Signal-to-Noise Ratio 2
Total Harmonic Distortion 1
Total Harmonic Distortion 2
SD Sensitivity
Local Oscillator Buffer Output
IF Counter Buffer Output
With no input signal
23dBµ, 30% modulation, fm = 1kHz
80dBµ, 30% modulation, fm = 1kHz
23dBµ, 30% modulation, fm = 1kHz
80dBµ, 30% modulation, fm = 1kHz
80dBµ, 30% modulation, fm = 1kHz
107dBµ, 30% modulation, fm = 1kHz
0% modulation
With no input signal
23dBµ
11
100
140
Conditions
Ratings
min
13
40
90
17
46
typ
27
80
160
23
52
0.4
0.5
20
140
285
1.1
1.3
29
200
400
max
39
160
230
Unit
mA
mVrms
mVrms
dB
dB
%
%
dBµ
mVrms
mVrms
No.7931-2/10
LA1845NV
Package Dimensions
unit : mm
3175B
Pin Description
Pin No.
1
Pin function
FM IF input
Pin voltage
Vreg
Equivalent circuit
Notes
Input impedance ri = 330Ω
1
3
2
AM mixer output
VCC
Connect the mixer coil between this pin and VCC
2
3
REG
2.1
3
Vreg = 2.1V
4
AM IF input
Vreg
Input impedance ri = 2kΩ
4
5
6
7
GND
Tu-LED
ST-LED/AF-IF
output
0V
VCC
Active low
6
7
Open collector
8
9
FM detector
VCC
VCC
The 600BEAS-10471 (Toko Mfg. Co., Ltd.) is
recommended for detector coil.
Continued on next page.
No.7931-3/10
LA1845NV
Continued from preceding page.
Pin No.
10
Pin function
AM/FM IF counter
output, output
control switch, mute
switch
Pin voltage
0V
Equivalent circuit
Notes
V10
≤0.5V
: Reception state
1.4V≤V10
≤2.2V
: Muting on
V10
≥3.5V
: IF counter output and muting on
10
11
Phase comparator
low-pass filter
(AM/FM switching)
VCC-1.0
11
The device operates in AM mode when a current of
over 200µA flows from pin. 12.
12
Pilot detector low-
pass filter (Forced
mono) (VCO stop)
VCC-1.0
12
The device is forced to monaural when a current of
over 50µA flows from this pin.
The VCO is stopped when a current of over 200µA
flows from this pin.
The limit values for the resistor are the same as
those for pin 11.
13
14
L outputs
R outputs
3.2V
Output impedance ro = 3.3kΩ
13
(
15
Pilot canceler
output
Vreg
14
)
15
3
16
Decoder input
Vreg
RNF
Inverting input pin
RNF = 20kΩ
16
17
PLL input
Vreg
Input impedance ri = 20kΩ
17
18
FM demodulator
output
Vreg+0.7
18
Output impedance ro = 2.3kΩ
The channel separation can be adjusted with an
external capacitor connected between this pin and
ground.
Continued on next page.
No.7931-4/10
LA1845NV
Continued from preceding page.
Pin No.
19
Pin function
AM detector output
Pin voltage
0V (FM)
1.5V (AM)
Equivalent circuit
Notes
Output impedance ro = 3.3kΩ
19
20
S meter,
AM AGC
0.2V (FM)
0.9V (AM)
The resistance of the built-in resistor R is 13.9kΩ.
The SD response during seek operation is
determined with the external capacitor connected to
this pin.
20
R
21
AM RF input
Vreg
Must be used at the same potential as pin 22.
21
22
AFC
Vreg
The FM SD bandwidth can be adjusted with the
external resistor connected between this pin and
pin 3 (Vreg).
22
23
OSC
VCC
23
Connect the oscillator coil between this pin and pin
9 (VCC).
Note : Impedance of the secondary oscillator coil
must be 5kΩ or higher.
24
Oscillator buffer
output,
FM SD sensitivity
adjustment
VCC-1.4
The FM SD sensitivity can be adjusted with an
external resistor connected to this pin.
R
24
Output impedance R = 200Ω
Note : Resistance of the external resistor
connected to the pin 24 must be 3.3kΩ or higher.
No.7931-5/10
PCB设计
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