FM IF System (Quadrature Detector) for Car Radio
Features
1.
On-chip IF count buffer circuit and microprocessor-
controlled switch circuit for ETR.
2.
Compared to the LA1140, the LA1145, 1145M offer:
1 Improved signal meter output linearity;
2 Improved band mute temperature stability;
3 Improved S/N ratio;
4 Improved sound quality at weak signal input when
noise is present, and;
5 Improved AMR characteristics during weak signal
input.
3.
Reduced parts' count simplifies design:
1 On-chip IF count buffer circuit;
2 On-chip SD circuit -- sensitivity can be set
independently of soft mute characteristics, and;
3 Variable S-meter gradient -- three pin S-meter output
(pins 5, 16 and 17) facilitates independent control of
SNC and HCC.
Package Dimensions
unit : mm
3115-SIP18Z
[LA1145]
SANYO : SIP18Z
unit : mm
3036B-MFP20
[LA1145M]
SANYO: MFP20
Ordering number: EN 2725A
Monolithic Linear IC
LA1145, 1145M
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
93097HS(II)/3132TS/2118TA No.2725-1/17
Specifications
[LA1145]
Maximum Ratings
at Ta = 25 C
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage
V
CC
max
Pin 12
14
V
Maximum supply current
I
CC
max
Pin 12
45
mA
Allowable power dissipation
Pd max
Ta = 65 C
630
mW
Ta = 70C
590
mW
Operating temperature
Topr
20 to +70
C
Storage temperature
Tstg
40 to +150
C
Operating Conditions
at Ta = 25 C
Parameter
Symbol
Conditions
Ratings
Unit
Recommended supply voltage
V
CC
8
V
Operating voltage range
V
CC op
7.5 to 14
V
Operating Characteristics
at Ta = 25C,V
CC
= 8 V, f
in
= 10.7 MHz
Parameter
Symbol
Conditions
min
typ
max
Unit
Quiescent current
I
CCO
V
IN
= 0 dB
18
26
36
mA
Current drain
I
CC
V
IN
= 100 dB
20
29
36
mA
Demodulation output
V
O
V
IN
= 100 dB, 400 Hz tone, 100%
300
400
520 mVrms
Total harmonic distortion
THD
V
IN
= 100 dB, 400 Hz tone, 100%,
single tuning coil
0.3
0.8
%
Signal-to-noise ratio
S/N
V
IN
= 100 dB, 400 Hz tone, 100%
79
85
dB
Input limiting voltage
V
IN
(lim)
400 Hz tone, 100%, soft mute ON
34
40
46
dB
Muting sensitivity
V
IN
(mute)
V
15
= 2 V
30
36
42
dB
Muting bandwidth
BW(mute)
V
IN
= 100 dB, V
18
%
0.3 V
140
190
280
kHz
Muting attenuation
mute(1)
V
IN
= 100 dB, V
15
= 2 V,
400 Hz tone, 100%
10
15
20
dB
mute(2)
V
IN
= 100 dB, V
15
= 4 V,
400Hz tone, 100%
25
29
33
dB
Signal strength indication output
V
16-0
V
IN
= 0 dB, R
A
= 10 k
, pin 16
0
0.1
0.4
V
V
16-50
V
IN
= 50 dB, R
A
= 10 k
, pin 16
1.4
2.3
3.2
V
V
16-70
V
IN
= 70 dB, R
A
= 10 k
, pin 16
2.5
4.5
5.5
V
V
16-100
V
IN
= 100 dB, R
A
= 10 k
, pin 16
5.0
5.5
6.0
V
Muting drive output
V
15-0
V
IN
= 0 dB, pin 15
4.0
4.8
5.5
V
V
15-100
V
IN
= 100 dB, pin 15
0
0
0.3
dB
AM rejection ratio
AMR
V
IN
= 100 dB, 1 kHz tone, 30% AM
57
70
dB
Offset voltage
V
7-11
V
IN
= 0 dB, pins 7 to 11
0.25
0
+0.25
V
V
8-11
V
IN
= 0 dB, pin 8 to 11
0.5
0
+0.5
V
SD sensitivity
V
SD
Pin 18
50
58
66
dB
IF count output level
V
IN
(IF)
V
IN
= 100 dB, pin 13, C
L
= 10 pF
110
180
280 mVrms
[LA1145M]
Maximum Ratings
at Ta = 25 C
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage
V
CC
max
Pin 13
14
V
Maximum supply current
I
CC
max
Pin 13
45
mA
Allowable power dissipation
Pd max
Ta = 70C, mounted on PC board,
independent IC
630
mW
Ta = 25C, mounted on PC board,
Independent IC
630
mW
Operating temperature
Topr
20 to +70
C
Storage temperature
Tstg
40 to +125
C
LA1145, 1145M
No. 2725-2/17
Operating Conditions
at Ta = 25C
Parameter
Symbol
Conditions
Ratings
Unit
Recommended supply voltage
V
CC
8
V
Operating voltage range
V
CC
op
7.5 to 14
V
Operating Characteristics
at Ta = 25 C, V
CC
= 8 V, f
in
= 10.7 MHz
Parameter
Symbol
Conditions
min
typ
max
Unit
Quiescent current
I
CCO
V
IN
= 0 dB
18
26
36
mA
Current drain
I
CC
V
IN
= 100 dB
20
29
40
mA
Demodulation output
V
O
V
IN
= 100 dB, 400 Hz tone, 100%
300
400
520 mVrms
Total harmonic distortion
THD
V
IN
= 100 dB, 400 Hz tone, 100%,
single tuning coil
0.3
0.8
%
Signal-to-noise ratio
S/N
V
IN
= 100 dB, 400 Hz tone, 100%
79
85
dB
Input limiting voltage
V
IN
(lim)
400 Hz tone, 100%, soft mute ON
34
40
46
dB
Muting sensitivity
V
IN
(mute)
V
16
= 2 V
30
36
42
dB
Muting bandwidth
BW (mute)
V
IN
= 100 dB, V
19
%
0.3 V
140
190
280
kHz
Muting attenuation
mute (1)
V
IN
= 100 dB, V
16
= 2 V,
400 Hz tone, 100%
10
15
20
dB
mute (2)
V
IN
= 100 dB, V
16
= 4 V,
400 Hz tone, 100%
25
29
33
dB
Signal strength
indication output
V
17-0
V
IN
= 0 dB, R
16
= 10 k
, pin 17
0
0.1
0.4
V
V
17-50
V
IN
= 50 dB, R
16
= 10 k
, pin 17
1.4
2.3
3.2
V
V
17-70
V
IN
= 70 dB, R
16
= 10 k
, pin 17
2.5
4.5
5.5
V
V
17-100
V
IN
= 100 dB, R
16
= 10 k
, pin 17
5.0
5.5
6.0
V
Muting drive output
V
16-0
V
IN
= 0 dB, pin 16
4.0
4.8
5.5
V
V
16-100
V
IN
= 100 dB, pin 16
0
0
0.3
V
AM rejection ratio
AMR
V
IN
= 100 dB, 1 kHz tone, 30% AM
57
70
dB
Offset voltage
V
8-12
V
IN
= 0 dB, pin 8 to 12
0.25
0
+0.25
V
V
9-12
V
IN
= 0 dB, pin 9 to 12
0.5
0
+0.5
V
SD sensitivity
V
SD
Pin 19
50
58
66
dB
IF count output level
V
IF
-On
V
IN
= 100 dB, pin 14, C
L
= 10 pF
110
180
280 mVrms
V
IF
-OFF
V
IN
= 100 dB, pin 14, C
L
= 10 pF
1
3 mVrms
Allowable
power
dissipation,
Pd
max
m
W
Ambient temperature, Ta C
Allowable
power
dissipation,
Pd
max
m
W
Mounted on PCB
(90
60
1.5 mm
3
glass epoxy
Independent
IC
Ambient temperature, Ta C
Pd max Ta
Pd max Ta
LA1145, 1145M
No. 2725-3/17
LA1145 Equivalent Circuit Block Diagram
LA1145M Equivalent Circuit Block Diagram
S-meter detector
Quadrature
detector
Voltage
regulator
IF amp
IF amp
IF amp
IF
count
Hole
detector/
mute
driver
Unit (resistance:
, capacitance: F)
S-meter
Mute
driver
S-meter
detector
Hole
detector/
mute
driver
Voltage
regulator
IF
count
Start point Gradient
* R
CT
is a resistor for variable gain.
Normally 0
.
LA1145, 1145M
No. 2725-4/17
Sample Application Circuit
LS1140 and LS1145 Compared
Parameter
LA1140
LA1145
Remarks
Package
SIP-16
SIP-18Z
MFP-20
IF amp, limiter
Direct-coupled
C-coupled
Quadrature detector
j
j
AF preamp
j
j
AFC output
j
j
Signal meter output
j
C
j
Improved linearity, variable S-meter gradient
Band muting
j
C
j
Improved temperature stability,
V
BE
dependent
IF count buffer output
j
Common with STRQ
SD circuit
j
For the LA1140, Coupled with the soft muting
function.
S/N
78 dB
86 dB
3 dB limiting sensitivity
25 dB (fixed)
25 to 40 dB
3 dB limiting sensitivity variable,
independent of soft muting function
Weak signal noise output
j
C
j
50 s
DC
emphasis
capacitor
Mute driver
output
S-meter
output
L1: 81N-014A (Sumida)
L2: 81N-014B (Sumida)
Unit (resistance:
, capacitance: F)
LA1145, 1145M
No. 2725-5/17
LA1145 Pin Description and Typical Voltages
Pin No.
Typical Voltage (V)
Description
Remarks
1
2.6
IF input
2
2.6
IF amp bias
3
0.0
IF amp GND
4
4.0
Mute start control
5
0.2
Mute gradient control
6
2.1
Mute attenuation control
7
4.9
AF output
8
5.0
AFC output
9
4.8
IF output
10
4.8
Quadrature detection input
11
4.8
Voltage regulator output
12
8.0
V
CC
13
0.1
IF count output, control
14
0.0
GND for detection circuit
15
4.8
Mute driver
16
0.2
S-meter output
17
0.2
SD sensitivity control
18
0.1
SD output
Open collector
LA1145M Pin Description and Typical Voltages
Pin No.
Typical Voltage (V)
Description
Remarks
1
NC
2
2.6
IF input
3
2.6
IF amp bias
4
0.0
IF amp GND
5
4.0
Mute start control
6
0.2
Mute gradient control
7
2.1
Mute attenuation control
8
4.9
AF output
9
5.0
AFC output
10
4.8
IF output
11
4.8
Quadrature detection input
12
4.8
Voltage regulator output
13
8.0
V
CC
14
0.1
IF count output, control
15
0.0
GND for detection circuit
16
4.8
Mute driver
17
0.2
S-meter output
18
0.2
SD sensitivity control
19
0.1
SD output
Open collector
20
NC
LA1145, 1145M
No. 2725-6/17
LA1145 Pin Functions (1)
Pin No.
Function
Internal Equivalent Circuit
Notes
1
IF input
2
Bias pin
3
GND
IF limiting amp
GND
4
Soft mute start point
control
For setting the soft mute starting point.
5
Soft muting gradient
control pin
Can be used for S-meter output.
For setting the mute gradient from the soft
mute starting point to the noise finishing
point.
6
Mute Att
For setting amount of mute attenuation.
The demodulation level changes when the
external resistance value is varied.
7
FM-AF output
8
AFC input
9
IF output
Output to the phase circuit
LA1145, 1145M
No. 2725-7/17
LA1145 Pin Functions (2)
Pin No.
Function
Internal Equivalent Circuit
Notes
10
IF input
IF input via the phase shift circuit. The mute
circuit malfunctions and demodulation output
decreases if the voltage level at this pin
drops below 180 mV.
11
Vref
4.8 V
12
V
CC
Supply voltage 7.5 to 14 V
13
IF buffer output
14
GND
FM detection circuit GND
15
Mute driver
Amount of mute attenuation depends on and
is controlled by the voltage at this pin.
16
S-meter output
PNP open collector output
17
SD sensitivity setting
Can be used for S-meter output
18
SD output
High active
LA1145, 1145M
No. 2725-8/17
SD Output Circuit
1.
LA1145 SD output differs from the LA1140's pin substitute SD output as shown below. The SD output on the LA1145 does
not operate in conjunction with the soft mute characteristics.
1)
LA1140
2)
LA1145
As shown, the SD output is the logical AND of the band mute and S-meter comparator outputs.
2.
Signal search using the SD output circuit
2-1 The transition response characteristics of the SD output circuit depends on the time constants of pins 15, 16, 17 and 8.
As the SD output transition response characteristics are determined by the pin with the largest time constant, erroneous
stopping will result when a search time is less than the largest one.
2-2 Band mute range circuit time constant (pin 8)
An equivalent circuit to the band circuit is shown below.
Hole detector
Signal meter
Mute driver
Band mute
output
Hole detector
Signal meter
Mute driver
Bandmute
output
Comparator
Exhibit hysteresis
Mute switch circuit
LA1145, 1145M
No. 2725-9/17
1)
Current path during detuning
2)
Current return path from detuning
As can be seen from the above circuit diagrams, the time constant during detuning is determined by the internal PNP
resistance, the NPN collector resistance and the capacitance of the externally- mounted capacitor. This time constant is
determined by the external resistance R
AFC
and capacitor C. This time constant,
= R
AFC
C, must be set depending on the
required search time.
3.
Narrow-band SD output circuit
An IF count circuit is provided for equipment compatibility for the European marketplace. However, if the band is made
narrow using only the SD circuit, there is a tendency for the number of erroneous stops caused by an undesired signal to
increase. To prevent this, two threshold voltages should be used to control the SD circuit.
The input/output current from pin 8 becomes zero during return.
SD output
SD sensitivity setting
Mute driver pin for the 2nd threshold voltage.
Band Mute Characteristics (1)
Without C
17
ANT
input
level
dB
Frequency,
f kHz
Band Mute Characteristics (2)
ANT
input
level
dB
With C
17
= 10000 pF
Frequency,
f kHz
LA1145, 1145M
No. 2725-10/17
Soft Mute Characteristics
1.
Control
The S/N setting (C/N) for weak inputs and the 3 dB limiting sensitivity can be controlled by obtaining the proper value for
the un-soft muted input/output signal characteristic. However, usable sensitivity cannot be controlled as this is determined by
the front end and IF design which are unrelated to soft muting.
2.
Soft mute setting
Soft mute operation depends on the S-meter circuit voltage and the hole
detection circuit voltage. As shown in the graph on the right, the degree
of soft muting correlates with the mute drive voltage, V15. The control
signal line of the mute drive voltage switches before and after the
10 dB ANT divergence point.
When adjusting the soft mute with a weak signal which does not affect
the S-meter, first adjust it using the hole detection input signal. However,
as the S-meter output will readjust the soft mute level, also adjust the
soft mute using the S-meter output. At this point, the hole detection
output adjusts the gain up to the IF input, causing a variance. Also, the
S-meter output is varied by the value of R
16
.
The LA1145 differs from the LA1140 in that it works with the internal
soft mute circuit continuously engaged.
3.
Soft mute transition response characteristic
The degree of soft muting automatically varies according to the change in input field strength. Omitting the influence of the
front end wideband AGC circuit, the LA1145's response speed is dependent on the time constant at pins 15 and 16.
Mute
drive
voltage
V
15
(Mute
attenuation)
Hole detector
S-meter
(Adjust R4, R5)
ANT input level (dB)
I/O Characteristics (R
CT
= 0
)
T
otal
harmonic
distortion,
THD
d
B
Demodulation
level
dBm/600
IF input level, dB
S-Meter
output
voltage
V
Mute Driver Voltage Characteristics
Mute
driver
voltage,
V
15
V
IF input level dB
I/O Characteristics (Mute Start Point)
Demodulation
level
dBm/600
ANT input level dB
Maximum
sensitivity
,
V
S
V
I/O Characteristics (Mute Gradient)
Demodulation
level
dBm/600
ANT input level dB
LA1145, 1145M
No. 2725-11/17
I/O Characteristics (Mute Attenuation Level)
Demodulation
level
dBm/600
ANT input level dB
I/O Characteristics
Demodulation
level
d
B
Mute driver
voltage (V
15
)
ANT input level dB
SD Sensitivity Temperature Characteristics
SD
Sensitivity
dB
Ambient temperature, Ta C
3 dB Limiting Sensitivity Temperature Characteristics
3
dB
limiting
sensitivity
dB
Ambient temperature, Ta C
SD Sensitivity Characteristics (IF input)
SD
sensitivity
(IF
input
level)
dB
(S-meter load resistor)
SD sensitivity resistor value
SD Sensitivity Characteristics (ANT input)
SD
ON
level
dB
17RSD-Adj resistor
I/O Characteristics
T
otal
harmonic
distortion,
THD
d
B
Demodulation
level
dBm/600
IF input level dB
S-Meter Characteristics (R
CT
= 0
)
Output
voltage
V
IF input level dB
LA1145, 1145M
No. 2725-12/17
Mute Driver Voltage
Output
voltage,
V
15
V
IF input level dB
Mute Driver Voltage
Mute
driver
voltage,
V
15
V
IF input level dB
Resistor-Dependent Mute Attenuation
Attenuation
d
B
S-level change
Attenuation
Mute driver voltage = 4 V
Attenuation setting resistor value
Load Resistance-Dependent Band Muting
Muting
range
kHz
Load resistance
AFC Characteristics
Frequency,
f kHz
IF Count Output Characteristics
IF
count
output
level
dB
IF input level dB
V
AFC
V
Current Drain Characteristics
Current
drain,
I
CC
m
A
Muting
IF input level dB
Power Supply-Dependent S-Meter Output Voltage
S-Meter
output
voltage,
V
16
V
Supply voltage, V
CC
V
LA1145, 1145M
No. 2725-13/17
Power Supply-Dependent Demodulation Output
Demodulation
output
m
V
rms
Supply voltage, V
CC
V
Power Supply-Dependent AMR
Supply voltage, V
CC
V
A
M
Rd
B
Power Supply-Dependent S/N
At 2V mute driver voltage
Supply voltage, V
CC
V
S
/
Nd
B
Muting Sensitivity Using Hole Detection Output
Muting
sensitivity
dB
Supply voltage, V
CC
V
Muting Attenuation Characteristics
Attenuation
d
B
Supply voltage, V
CC
V
Power Supply-Dependent Mute Driver Voltage
Mute
driver
voltage
V
Supply voltage, V
CC
V
Power Supply-Dependent Muting Bandwidth
Muting
bandwidth
kHz
Supply voltage, V
CC
V
Tuning Point Shift
T
uning
drift,
f
kHz
Supply voltage, V
CC
V
LA1145, 1145M
No. 2725-14/17
Current Drain Characteristics
Current
drain,
I
CC
m
A
Supply voltage, V
CC
V
I/O Characteristic (R
CT
= 0
)
Demodulation
level
shift
d
B
Ambient temperature, Ta C
I/O Characteristics (R
CT
= 0
)
Demodulation
output
dBm/600
Pin 15 short
IF input level dB
I/O Characteristics (R
CT
= 100
)
Demodulation
level
shift
d
B
Ambient temperature, Ta C
I/O Characteristics (R
CT
= 100
)
Demodulation
output
dBm/600
Pin 15 short
IF input level dB
I/O Characteristics (R
CT
= 510
)
Demodulation
level
shift
d
B
Ambient temperature, Ta C
I/O Characteristics (R
CT
= 510
)
Demodulation
output
dBm/600
Pin 15 short
IF input level dB
S-Meter Characteristics (Temperature Characteristic)
S-Meter
output
voltage
V
IF input level dB
LA1145, 1145M
No. 2725-15/17
3 dB Limiting Sensitivity Temperature Characteristics
3
dB
limiting
sensitivity
dB
Pin 15 short
Ambient temperature, Ta C
Muting Attenuation Characteristics
Muting
attenuation
d
B
Ambient temperature, Ta C
Muting Bandwidth Temperature Characteristics
Muting
bandwidth
kHz
Ambient temperature, Ta C
AMR Temperature Characteristics
Ambient temperature, Ta C
A
M
Rd
B
IF Count Output Level Shift
IF
count
output
level
dB
IF input level dB
THD Characteristic (Single Tuning Circuit)
T
otal
harmonic
distortion,
THD
d
B
V
AFC
= 0 V
IF input level dB
THD Detuning Characteristics
T
otal
harmonic
distortion,
THD
d
B
V
AFC
= 0 V
Detuning frequency kHz
LA1145, 1145M
No. 2725-16/17
No products described or contained herein are intended for use in surgical implants, life-support systems,
aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like,
the failure of which may directly or indirectly cause injury, death or property loss.
Anyone purchasing any products described or contained herein for an above-mentioned use shall:
1
Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and
distributors and all their officers and employees, jointly and severally, against any and all claims and litigation
and all damages, cost and expenses associated with such use:
2
Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on
SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees
jointly or severally.
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 September, 1997. Specifications and information herein are subject to change without notice.
LA1145, 1145M
No. 2725-17/17
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