AN7280S [PANASONIC]
FM Front-end IC for Car Radio; FM前端IC，车载电台
| 型号： | AN7280S |
| 厂家： | 
PANASONIC |
| 描述： | FM Front-end IC for Car Radio |
| 文件： | 总7页 (文件大小：83K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ICs for FM/AM Tuner
AN7280S
FM Front-end IC for Car Radio
■ Overview
Unit : mm
The AN7280S is an FM front-end IC designed for DTS
except RF amp. of car radio. It features built-in local oscil-
lation frequency buffer output, PIN diode driver for anten-
na damping and SSC (search stop control).
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
■ Features
6
7
•
•
•
•
•
High sensitivity, high S/N ratio
Good IM characteristics at strong input
Available for two loop AGC (keyed AGC)
Pre IF amp. gain variable
8
9
10
PIN diode driver (ADX) built-in
0.3
5.4±0.3
7.7±0.3
20-Lead SOP Package (SOP020-P-0300B)
■ Block Diagram
GND
20
19
18
17
16
15
14
13
12
11
IF Amp.
ADX
Mixer
VREG
SSC
Buffer
Buffer
AGC Amp.
OSC
Det.
5
1
2
3
4
6
7
8
9
10
GND
VCC
ICs for FM/AM Tuner
AN7280S
■ Absolute Maximum Ratings (Ta=25˚C)
Parameter
Symbol
Rating
9.2
Unit
V
Supply Voltage
Supply Current
VCC
ICC
50
mA
mW
˚C
Power Dissipation
PD
460
Operating Ambient Temperature
Storage Temperature
Topr
Tstg
–40 ~ + 85
–55 ~ + 150
˚C
■ Recommended Operating Range (Ta=25˚C)
Parameter
Symbol
VCC
Range
Operating Supply Voltage Range
6.8V ~ 9.2V
■ Electrical Characteristics (Ta=25˚C)
Parameter
Symbol
min.
22
typ.
30
max.
435
Unit
dB
Condition
VCC= 8V, Vin=17dBµNo modulation
However, S= output at 400Hz, 30%modulation
NOUT
S/N Ratio
VCC= 8V, fOSC= 108.7MHz
Measured by Pin4, No signal input
Local Oscillation Level
219
41
384
mV
VOSC
IF Output Level
AGC Level (L)
AGC Level (H)
VCC= 8V, Vin= 51dBµ
VOUT
VAGC (L)
VAGC (H)
58
0.05
6.5
82
mV
V
VCC= 8V, Vin= 67dBµ
VCC= 8V, Vin= 53dBµ
0.5
6
V
■ Characteristics Curve
Level · Diagram
Input/Output Characteristics
Frequency Change
50
VCC=8V
fin=1kHz
VCC=8V
fin=98MHz
Mod.=22.5kHz
fm=1kHz
IF : AN7256
400Hz HPF ON
43.5 (max.)
40
30
20
10
0
Mod.=22.5kHz
IF : AN7256
20
15
10
5
0
–20
–40
–60
–80
24.5
16.0 (min.)
Practical Sensitivity (S/N=30dB)
Limiting Sensitivity
13.5
8.5
0
–5
–10
–15
Residual Noise
0.01µF
IFT
IF
OUT
IF–Amp.
IN
Mix.
MS3
330Ω
080
0
20
40
60
80
88 90 92 94 96 98 100102 104 106 108
in (MHz)
V
in (dBµV)
f
ICs for FM/AM Tuner
AN7280S
Amp. Gain Adjustment
with AGC
IF-Amp. Gain Adjustment
AGC ON Level
110
100
90
VCC = 8V
VCC= 8V
IF Amp.
13
f=10.7MHz
Input
Output
330Ω
fin
= 98MHz No Adjustment
f
in = 18MHz
110
100
90
80
70
60
50
0
Pin7 = HIGH
Radj. is Piny external resistance
(AGC Start Point Variable)
40
30
20
10
0
Radj.= 0Ω
80
Pin9 =
High
27dB
70
Radj.= ∞
Pin9 = Low
60
50
0
1k
10K
∞
0
1
1.4
1.8
2.2
4
0
1k
10K
∞
Pin13 Adjusting Resistance (Ω)
Pin7 Vcont in (V)
Pin6 Adjusting Resistance (Ω)
Supply Voltage Dependence
Supply Voltage Dependence
Supply Voltage Change
No Input
No Input
35
30
25
20
15
10
5
11
10
9
110
100
Local Oscillation Level
AGC ON Level
5
4
3
2
1
0
5
4
3
2
1
0
Vt
60
50
8
Vref
Itot
7
SSC ON Level
6
20
10
0
Practical Sensitivity
Limiting Sensitivity
5
0
4
0
2
4
6
8
10
12
5
6
7
8
9
10 11 12
6
7
8
9
10
V
CC (V)
V
CC (V)
VCC (V)
Total Gain
Temperature Characteristics
AGC Start Point
Temperature Characteristics
Temperature Characteristics
10
8
105
100
95
90
85
80
75
70
65
60
55
80
70
60
50
40
30
20
10
0
Mixer+IF–Amp.
VCC= 8V
IC for IF/DET
is normal temperature
Pin7=1V
Pin6=GND
Pin9=OPEN
6
4
AGC ON Level (max. Gain)
2
Pin7=HIGH
Pin6=GND
Pin9=OPEN
0dB= 43.5dB
0
–2
–4
–6
–8
–10
Pin7=HIGH
Pin6=OPEN
Pin9=5V
Practical Sensitivity (S/N=30dB)
Limiting Sensitivity
Pin7=HIGH
Pin6=OPEN
Pin9=OPEN
–40 –20
0
20 40 60 80 100
Ta (˚C)
–40 –20
0
20 40 60 80 100
Ta (˚C)
–60 –40 –20
0
20 40 60 80 100
Ta (˚C)
ICs for FM/AM Tuner
AN7280S
IF Amp. Output Saturation Level
SSC ON Level
Temperature Characteristics
Temperature Characteristics
5
4
5
4
3
2
1
0
VCC=8V
SSC Input Pin
9
3
2
1
0
–1
–2
–3
–4
–5
–40 –20
0
20 40 60 80 100
Ta (˚C)
–40 –20
0
20 40 60 80 100
Ta (˚C)
■ Application Circuit
VCC
ANT
KVC–1340
22Ω
3SK1311
0.001µF 18pF
MA551
18pF
KVC–1340
Produced by MATSUSHITA
IFT : ZIF–5EF021B
330Ω C–F
1kΩ
To IF
20
19
18
17
16
15
14
IF
13
12
11
GND PIN RF Pass Mix Mix
IF Pass IF
D
AGC
IN Con. OUT OUT IN Gain Con. OUT
Adj
AN7280S
AGC
Pass OSC
Gain 2 Loop
E
1
B
2
C
OUT AGC Adj
IN GND SSC VCC
3
4
5
6
7
8
9
10
180kΩ
56pF
+
–
120kΩ
1µF
VT
KVC–1340
5V 5V
At Normal
0V
0V
Control
Voltage
At Search
ICs for FM/AM Tuner
AN7280S
■ Pin Descriptions
Pin No.
Pin Name
Description
Equivalent Circuit
Vref
1
OSC Emitter
Local oscillation transistor emitter pin
2
1
2
3
OSC Base
Local oscillation transistor base pin
5V
+
–
Vref by-pass pin for mixer,OSC buffer,OSC
section
OSC By-pass
3
Vref
4
5
6
OSC Buffer Output
Pin for output OSC signal to pre-scaler
4
750Ω
VCC
.70µA
AGC signal output pin for RF-Amp.
secondary gate
Level Detection Output
5
Pin for adjusting AGC Amp. gain by
external resistance
AGC– Amp. Gain Adjustment
6
5.6kΩ
1.5kΩ
Pin for adjusting AGC-Amp. gain through
input of control signal from IF section
7
7
8
Control Signal Input
1.5V
GND
Vref
9
Pin for adjusting AGC-Amp. gain through
input of control signal from microcomputer
70kΩ
39kΩ
9
SSC Input
10
VCC
ICs for FM/AM Tuner
AN7280S
■ Pin Descriptions (Cont.)
Pin No.
Pin Name
Description
Equivalent Circuit
11
11
IF-Amp.
IF-Amp. output pin
240Ω
3kΩ
ZOUT.300Ω
12
14
IF-Amp. By-pass
IF-Amp. Input
IF-Amp. by-pass pin
IF-Amp. input pin
12
14
330Ω
340Ω
Pin for adjusting IF-Amp. gain by external
resistance
13
13
IF-Amp. Gain Adjustment
12kΩ
15
16
15
16
17
18
Mix. Output
Mixer output pin
2.2kΩ
2.2kΩ
Mix. By-pass
Mix. Input
Mixer by-pass pin
Mixer input pin
17
18
VCC
PIN diode driver output pin
Determine maximum current to PIN diode
by Pin19 external resistance value.
19
20
ADX Output
GND
19
Oscillator GND
ICs for FM/AM Tuner
AN7280S
■ Operational Description
• Loop AGC
The AN7280S uses 2Loop AGC for AGC circuit. 2Loop AGC controls AGC output by using mixer output (IFT first side)
signal and FM–IF control voltage (level meter output), which is a very favorable system for disturbance characteristics,
etc.
IFT
IF–Amp.
FM–IF
To N.C.
RF–Amp.
Mixer
Control Voltage Output
AGC
Amp.
AGC
Det.
• AGC start point (Mixer input level at VAGC < 3V) changes in proportion to Pin6 external resistance (following R1), Pin
7 applied voltage (Determine IF control voltage by R2 R3 resistance division) SSC ON/OFF
,
· Variable width at R 1 28dB (however, V7 ≥3V, V9 = 0V)
· Variable width at R 40dB (however, R = , V = 0V)
∞
7
1
9
· Variable width at R 10dB (however, R = , V ≥3V)
∞
9
1
7
VREF
3
AGC Output AGC–Adj
Vcont IN
7
SSC IN
9
5
6
R2
about 4.7V
R1
VAGC
R3
from microcomputer
FM–IF
Control voltage
• SSC
Change AGC start point by microcomputer control signal at seek/reception time.
Use at SSC ON ········V9 > 3.5V
Use at SSC OFF········V9 < 1.5V
* SSC is designed as precondition for switching operation at microcomputer control signal.
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