CXA1991N
FM Pager/FM Multiplex Tuner
Description
The CXA1991N is a tuner IC designed for use in
FM pagers and FM multiplex broadcasting. A
receiver system can be configured by using the
digital data output, in combination with a decoder. It
has a battery save function and ultra-low power
consumption.
Features
•
Ultra-low power consumption
(I
D
= 1.2 mA for FM; I
D
= 0.8 mA for AM; V
CC
= 3 V)
•
LED drive circuit for tuning
•
Battery save function
•
Few external parts
Applications
•
Tuners for FM multiplex broadcasting
•
FM pagers
20 pin SSOP (Plastic)
Absolute Maximum Ratings
(Ta=25 °C)
•
Supply voltage
•
Operating temperature
•
Storage temperature
V
CC
Topr
Tstg
14
–20 to +75
–65 to +150
400
V
°C
°C
mW
•
Allowable power dissipation
P
D
Operating Conditions
Supply voltage
V
CC
1.8 to 4.5
V
Block Diagram
FM MIX
AM OSC
GND 1
FM RF
FM OSC
FE OUT
AM IN
FM IN
REG
TUNE
11
20
19
18
17
16
15
14
13
12
FM FRONT END
REG
METER
AM FRONT END
AGC BUFF
AM IF, IF DET
AGC
FM IF DET
BATTERY
SAVE CONT
1
2
3
4
5
6
7
8
9
10
FM IF
BAND
GND 2
DISCRI
AM IF
Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by
any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the
operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.
—1—
DET OUT
AGC
AFC
E95925B8Y
V
CC
B.S
CXA1991N
Pin Description
Pin
No.
Symbol
Pin voltage (V)
FM
AM
Equivalent circuit
(V
CC
=3 V, Ta=25 °C)
Description
220k
1
AM IF IN
1.1
1.1
1
AM IF input pin.
2
AGC
0.3
0.4
2
130 100k
130
Connected to a capacitor.
9
9
DET OUT
0.9
0.7
Detection output pin.
3
FM IF IN
1.1
0
V
CC
V
CC
FM IF input pin.
330
3
4
4
BAND
1.1
0
AM/FM band switching pin.
AM when grounded, FM when
open.
IF system ground.
5
GND2
0
0
V
CC
6
DISCRI
2.0
2.4
2k
6
1.1k
Connected to phase shift circuit
and ceramic discriminator.
7
V
CC
3.0
3.0
—2—
CXA1991N
Pin
No.
Symbol
Pin voltage (V)
FM
AM
Equivalent circuit
Description
8
160k
8
BS
550k
Controls battery save via
microcomputer.
High = Active, Low = Save
10
AFC
1.0
0.7
10
200k
REG
AFC varicap pin.
13
13
FM OSC
1.1
1.1
FM local oscillation circuit.
11
TUNE
1.1
1.1
11
V
CC
AM/FM tuning indicator drive
circuit.
REG
12
AM OSC
1.1
1.1
12
AM local oscillation circuit.
V
CC
14
REG
1.1
1.1
14
Regulator output pin.
—3—
CXA1991N
Pin
No.
Symbol
Pin voltage (V)
FM
AM
Equivalent circuit
V
CC
REG
11p
10k
Description
15
FM MIX
1.1
1.1
15
Load for mixer which resonates
at 10.7 MHz from internal
capacitance and external coil.
V
CC
16
FM RF
1.1
1.1
50k
18
5k
FM RF amplifier circuit which is
connected to RF tank circuit
REG
16
18
FM RF IN
2.2
2.4
FM RF amplifier circuit which is
FM RF input.
V
CC
17
AM RF IN
1.1
1.1
17
AM RF input which is
connected to bar antenna.
19
GND1
0
0
V
CC
Front-end ground.
15
20
FM Block
20
FE OUT
0.6
1.5
3k
AM Block
AM/FM IF output pin which is
connected to IF filter.
—4—
Electrical Characteristics
Bias and SW conditions
MIN Limit
Min. Typ. Max.
Input
Input waveform and
bias description
point
measurement method description
BS
TUNE
FEOUT
point
Measurement
Output waveform and
Unit
S3
S4
S5
V
CC
=3 V, Ta=25 °C
S1
S2
Measurement
Standard Bias Conditions
OFF
—
A1
AM no signal
OFF
OFF
FM no signal
0.60 1.25 1.90
mA
Functional block
Measurement No.
1
Current consumption
for FM no signal
—
ON
—
Vin=40 dBµV,
100 MHz CW
Vin=90 dBµV, 10.7 MHz
22.5 kHz DIV
Vin=90 dBµV, 10.7 MHz
22.5 kHz DIV
Vin=90 dBµV, 10.7 MHz
75 kHz DIV
Vin=90 dBµV,
10.7 MHz CW
ON
Vin=60 dBµV,
10.7 MHz CW
ON
V1
Vin=75 dB µV,
1660 kHz CW
Vin=455 kHz,
30 %mod
Vin=80 dBµV,
455 kHz, 30 %
ON
Vin=80 dBµV,
455 kHz
V1
Vin=100 dBµV,
1660 kHz, 30 %
9 pin-
14 pin
A2
VB
VD
V3 level when VB level for input of
V3 = 90 dBµV drops by –3 dB.
VA
OFF
OVER
OFF
2
Current consumption
for AM no signal
ON
BAND
item
0.30 0.75 1.20
mA
3
OFF
V2
Current consumption
for battery save
OFF
—
10.7 MHz
—
1.00
µA
4 FM front-end gain
ON
OFF
10
20
30
dB
5
FM detection
V3
output level
39.0 73.5 123.5 mVrms
6 FM IF knee level
22.5 33.0 43.5 dBµV
—5—
OFF
VA
V4
VD
VD
A2
OFF
VB
7
FM detection
output distortion
—
Frequency offset from 10.7 MHz when Pin
9-Pin 14 DC potential difference is 0 mV.
0.3
1.0
%
8
IF center
frequency offset
–50
0
50
kHz
9 FM meter current
1.25 2.90 4.45
455 kHz
mA
10 AM front-end gain
ON
25
28
31
dB
VIN level for –40 dBm output. 25.0 29.0 33.0 dBµV
11 AM IF gain
12
AM detection
output level
43.5 65.5 98.0 mVrms
13 AM meter current
1.50
2.9
4.30
mA
14
AM detection
output distortion
OFF
—
0.60 3.00
%
CXA1991N
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