ta7792

TIGER ELECTRONIC CO.,LTD
AM/FM 1 CHIP TUNER SYSTEM IC (1.5V USE)
TA7792
G ENERAL DESCRI PTI O N
The TA7792 is AM/FM 1 chip tuner system (FM FRONT END+AM/FM IF) ICs,
w h i c h i s d e s i g n e d f o r l o w v o l t a g e o p e r a t i o n ( 1 . 5 V, 3 . 0 V ) . T h o s e a r e e s p e c i a l l y
suitable for stereo headphone radio and radio cassette recorder equipments. These
item can realize the low power dissipation and few external parts.
FEATURES
AM detector coil-less
FM mixer coil-less
Switchover between AM/FM mode is possible with one-make switch.
Operating supply voltage range:
V c c ( o p r ) = 0 . 9 5 ~ 5 V ( Ta = 2 5 ° C )
E x c e l l e n t l o w s u p p l y c u r r e n t ( V c c = 1 . 5 V, Ta = 2 5 ° C )
I c c ( A M ) = 1 . 2 m A ( Ty p . )
I c c ( F M ) = 4 . 0 m A ( Ty p . )
BLOCK DIAGRAM
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TA7792
D7792
PIN CONNECTION
FM MIX
1
16
FM RF
AM/FM
SW
2
15
GND
FM OSC
3
14
FM IF1
AM OSC
4
13
AM RF
12
FM IF2
TA7792
D7792
AM MIX
5
AM AGC
6
11
GND
AM IF
7
10
Vcc
AF
8
9
FM DET
TERMINAL VO LTAGE:
Te r m i n a l v o l t a g e a t n o s i g n a l w i t h t e s t c i r c u i t ( V c c = 1 . 5 V, Ta = 2 5 ° C )
1
2
3
4
5
6
7
8
Pin No.
SymPin Name
bol
FM RF OUT
V1
Vcc1
V2
FM OSC
V3
AM OSC
V4
AM MIX OUT V5
AM AGC
V6
AM IF IN
V7
AF OUT
V8
Ty p .
AM FM
1.5
1.5
1.5
1.5 1.5
1.5 1.5
0.8
1.4 1.5
0.6 0.6
Unit
V
V
V
V
V
V
V
V
9
10
11
12
13
14
15
16
Pin No.
SymPin Name
bol
FM DET
V9
Vcc2
V10
GND2
V 11
FM IF IN
V12
AM RF IN
V13
FM MIX OUT V14
GND1
V15
FM RF IN
V16
Ty p .
Unit
AM FM
1.5 1.5
V
1.5 1.5
V
0
0
V
0.7
V
0.7
V
0.8
V
0
0
V
0.7
V
MAXIMUM RATINGS ( Ta = 2 5 ° C )
Characteristics
Symbol
Rating
Unit
S u p p l y Vo l t a g e
Vcc
5
V
Power Dissipation
PD
O p e r a t i n g Te m p e r a t u r e
To p r
-25~75
°C
St o r a g e Te m p e r a t u r e
Ts t g
-55~150
°C
750(DIP)
350(SOP)
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ELECTRICAL CHARACTERISTICS ( V c c = 1 . 5 V, Ta = 2 5 ° C )
Characteristics
Symbol
Supply Current
Icc
Output Resistance Pin 8
Ro
Te s t
C i rCuit
1
Te s t C o n d i t i o n
Min.
Ty p . M a x .
F M : Vi n = 0
-
4.0
5.2
1
A M : Vi n = 0
-
1.2
1.8
1
FM:f=1kHz
-
1.4
-
1
AM: f=1kHz
-
8.0
-
Unit
mA
kΩ
A M : Vi n = 6 0 d B µ V E M F, f = 1 M H z , f m = 1 K H z , M O D = 3 0 %
Vo l t a g e G a i n
Gv
R e c o v e r e d O u t p u t Vo l t a g e V O D
To t a l H a r m o n i c
THD
Distortion
S i g n a l To N o i s e R a t i o
S/N
O s c i l l a t o r St o p S u p p l y
Vstop
Vo l t a g e
F M : Vi n = 6 0 d B µ V E M F, f = 8 3 M H z ,
1
Vi n = 3 0 d B µ V E M F
14
25
50
m Vr m s
1
-
25
40
60
m Vr m s
1
-
-
1.5
-
%
Vi n < - 2 0 d B µ V
1
EMF
fm=1kHz, Δ f=±22.5kHz
40
-
dB
1
0.85 0.95
V
Vi n ( l i m )
1
-3dB limiting
-
10
16
dBµV
EMF
THD
1
-
-
0.25
-
%
S/N
1
-
-
62
-
Quiescent Sensitivity
Qs
1
S/N=30dB
-
12
-
AM Rejection Ratio
AMR
MOD=30%
-
30
-
dB
dBµV
EMF
dB
O s c i l l a t o r Vo l t a g e
O s c i l l a t o r St o p S u p p l y
Vo l t a g e
Recovered Output
Vo l t a g e
Vo s c
2
53
90
Vstop
1
F=60MHz
Vi n < - 2 0 d B µ V
EMF
-
0.85
0.95
V
VOD
1
-
28
45
68
m Vr m s
I n p u t L i m i t i n g Vo l t a g e
To t a l H a r m o n i c
Distortion
S i g n a l To N o i s e R a t i o
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TEST CIRCUIT
TA7792
TEST CIRCUIT 1
TA7792
TEST CIRCUIT 2
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COIL DATA （ T E S T C I R C U I T ）
L
TEST
Co
FREQUENCY （ µH） (pF)
C O I L S TA G E
Qo
TURN
1-2
2-3
1-3
4-6
WIRE
(mmΦ)
L1 FM RF
100MHz
0.053
-
100
-
-
1.75
-
0.5UEW
L2 FM OSC
100MHz
0.065
-
100
-
-
2.25
-
0.5UEW
T1 AM OSC
796kHz
288
-
11 5
13
73
-
-
0.08UEW
T2 AM IFT
455kHz
-
180
120
-
-
180
15
0.06UEW
T3 FM DET
10.7MHz
-
82
11 0
-
-
13
-
0.12UEW
APPLICATION NOTE
<FM SECTION>
RF amplifier (see Fig.1)
T h i s s t a g e i s c o m p o s e d o f t h e e m i t t e r- g r o u n d e d
a n d c a s c a d e c o n n e c t i o n a m p l i f i e r.
The input impedance of pin 16 is about 260Ω,
which is determined by D1.
Mixer amplifier (see Fig.2)
The amplified RF signal is transformed into
IF
signal
by
the
mixer
circuit
which
is
c o m p o s e d o f a d i ff e r e n t i a l a m p l i f i e r.
The amplified IF signal is appeared through
the emitter follower circuit at pin 14. The
o u t p u t i m p e d a n c e o f t h e c e r a m i c f i l t e r.
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(note)
the spurious characteristic is determined by the characteristic of the ceramic
filter (10.7MHz), because the mixer coil is dispensable. It is possible to
improve the spurious characteristic that the two ceramic filters of different
characteristics are connected in series.
IF limiter amplifier (see Fig.3)
The
IF
limiter
amplifier
is
composed
of
six
e m i t t e r- g r o u n d e d a m p l i f i e r s a n d a d i f f e r e n t i a l a m p l i f i e r.
T h e b a s i s c o m p o s i t i o n o f t h e e m i t t e r- g r o u n d a m p l i f i e r s
is shown as Fig.3
Detector circuit
This stage is composed of the quadrature detector
circuit, which has double banlanced.
<AM SECTION>
RF amplifier (see Fig.4)
T h i s s t a g e i s c o m p o s e d o f e m i t t e r- g r o u n d e d
a m p l i f i e r, t h e i n p u t i m p e d a n c e o f w h i c h h a s
about 7.3kΩ. It is necessary to connect as
Fig.4,
because
available
to
the
the
c o n d e n s e r,
audio
by-pass
C1
of
is
the
R F - A G C , t h e n o i s e o f l o w f r e q u e n c y.
Mixer circuit
The amplified RF signal is transformed into
IF signal by the mixer circuit, which is
c o m p o s e d o f a d i ff e r e n t i a l a m p l i f i e r.
IF amplifier
T h i s s t a g e i s c o m p o s e d o f f o u r e m i t t e r- g r o u n d e d a m p l i f i e r s a n d t h e t w o
d i ff e r e n t i a l a m p l i f i e r s . T h e i n p u t i m p e d a n c e i s r a t h e r h i g h , b e c a u s e i t i s
changed by the amplitude of input signal (AGC level). So the input terminal of
t h e I F a m p l i f i e r m u s t b e m a t c h e d w i t h t h e i m p e d a n c e o f c e r a m i c f i l t e r.
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TA7792
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<COMMON SECTION>
AM/FM mode switchover
Switchover between AM/FM mode is possible with one-make switch. In case of
the opened, this IC has AM mode.
A n o t h e r i n c a s e t h a t t h e t e r m i n a l i s c o n n e c t e d t o V c c d i r e c t l y, t h a t h a s F M
mode.
And the terminal of pin 2 is Vcc terminal of FM FRONT END section, too.
Output circuit (see Fig.5)
Both of the AM/FM detector signal is appeared
TA7792
D7792
through the pin 8.
T h o s e o u t p u t a r e c h o s e n b y t h e m o d e s w i t c h o v e r.
8
C1
C2
8
TA7766AF
560pF
At the same time, the output impedance is changed as follow at AM/FM mode,
d u e t o c u t t h e A M c a r r i e r s i g n a l a n d p a s s t h e F M c o m p o s i t e s i g n a l s m o o t h l y,
w i t h o n l y o n e c o n d e n s e r.
R o u t ( A M ) = 8 k Ω ( Ty p . )
R o u t ( F M ) = 1 . 4 k Ω ( Ty p . )
CHARACTERISTICS CURVES
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O u t l i n e D r a wi n g
DIP16 ：
TA7792
SOP16
TA7792
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