CXA1991N
FM Pager/FM Multiplex Tuner
For the availability of this product, please contact the sales office.
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
(ID = 1.2 mA for FM; ID = 0.8 mA for AM; VCC = 3 V)
• LED drive circuit for tuning
• Battery save function
• Few external parts
20 pin SSOP (Plastic)
Absolute Maximum Ratings (Ta=25 °C)
• Supply voltage
VCC
14
V
• Operating temperature
Topr –20 to +75 °C
• Storage temperature
Tstg –65 to +150 °C
• Allowable power dissipation
400
mW
PD
Applications
• Tuners for FM multiplex broadcasting
• FM pagers
Operating Conditions
Supply voltage
VCC
1.8 to 4.5
V
FE OUT
GND 1
FM IN
AM IN
FM RF
FM MIX
REG
FM OSC
AM OSC
TUNE
Block Diagram
20
19
18
17
16
15
14
13
12
11
REG
FM FRONT END
METER
AM FRONT END
AM IF, IF DET
AGC
BATTERY
SAVE CONT
1
2
3
4
5
6
7
8
9
10
AGC
FM IF
BAND
GND 2
DISCRI
VCC
B.S
DET OUT
AFC
FM IF DET
AM IF
AGC BUFF
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—
E95925B8Y
CXA1991N
Pin Description
(VCC=3 V, Ta=25 °C)
Pin
No.
Symbol
Pin voltage (V)
FM
AM
1
AM IF IN
1.1
1.1
2
AGC
0.3
0.4
Equivalent circuit
Description
220k
1
AM IF input pin.
Connected to a capacitor.
130
2
9
130 100k
9
DET OUT
0.9
0.7
3
FM IF IN
1.1
0
Detection output pin.
VCC
VCC
FM IF input pin.
330
3
4
4
BAND
1.1
0
AM/FM band switching pin.
AM when grounded, FM when
open.
5
GND2
0
0
IF system ground.
VCC
6
DISCRI
2.0
2.4
2k
6
1.1k
7
VCC
3.0
3.0
—2—
Connected to phase shift circuit
and ceramic discriminator.
CXA1991N
Pin
No.
Symbol
Pin voltage (V)
FM
AM
Equivalent circuit
160k
8
8
BS
10
AFC
Description
Controls battery save via
microcomputer.
High = Active, Low = Save
550k
1.0
0.7
10
REG
AFC varicap pin.
200k
13
13
FM OSC
1.1
1.1
11
TUNE
1.1
1.1
FM local oscillation circuit.
VCC
11
AM/FM tuning indicator drive
circuit.
REG
12
AM OSC
1.1
1.1
12
AM local oscillation circuit.
VCC
14
REG
1.1
1.1
Regulator output pin.
14
—3—
CXA1991N
Pin
No.
Symbol
Pin voltage (V)
FM
AM
Equivalent circuit
VCC
Description
REG
11p
Load for mixer which resonates
at 10.7 MHz from internal
capacitance and external coil.
10k
15
FM MIX
1.1
1.1
15
VCC
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
FM RF amplifier circuit which is
FM RF input.
2.4
VCC
17
AM RF IN
19
GND1
1.1
1.1
0
0
AM RF input which is
connected to bar antenna.
17
Front-end ground.
VCC
15
20
20
FE OUT
0.6
FM Block
AM/FM IF output pin which is
connected to IF filter.
1.5
3k
AM Block
—4—
Functional block
Measurement No.
for battery save
Current consumption
for AM no signal
Current consumption
for FM no signal
Current consumption
output level
FM detection
—5—
OFF
V1
ON
output distortion
AM detection
OFF
V1
1660 kHz, 30 %
Vin=100 dBµV,
455 kHz
Vin=80 dBµV,
455 kHz, 30 %
30 %mod
Vin=455 kHz,
Vin=80 dBµV,
V4
1660 kHz CW
Vin=75 dB µV,
output level
13 AM meter current
14
ON
10.7 MHz CW
AM detection
11 AM IF gain
OFF
10.7 MHz CW
Vin=60 dBµV,
Vin=90 dBµV,
frequency offset
22.5 kHz DIV
Vin=90 dBµV, 10.7 MHz
22.5 kHz DIV
Vin=90 dBµV, 10.7 MHz
100 MHz CW
Vin=40 dBµV,
AM no signal
FM no signal
IF center
ON
V3
V2
—
—
—
75 kHz DIV
OFF
OFF
bias description
Input waveform and
Vin=90 dBµV, 10.7 MHz
ON
OFF
ON
OFF
point
Input
output distortion
10 AM front-end gain
12
ON
OFF
ON
OFF
S1
OVER
OFF
S2
BAND
OFF
S3
BS
FM detection
9 FM meter current
8
7
6 FM IF knee level
5
4 FM front-end gain
3
2
1
Standard Bias Conditions
item
Measurement
S5
S4
TUNE
Bias and SW conditions
FEOUT
Electrical Characteristics
VB
A2
VD
VD
VA
A2
14 pin
9 pin-
VB
VD
VA
A1
point
Measurement
20
—
30
1.00
dB
µA
mA
mA
0
0.3
50
1.0
25
28
31
1.25 2.90 4.45
–50
—
dB
mA
kHz
%
22.5 33.0 43.5 dBµV
39.0 73.5 123.5 mVrms
10
—
0.30 0.75 1.20
0.60 1.25 1.90
Unit
—
1.50
4.30
0.60 3.00
2.9
%
mA
43.5 65.5 98.0 mVrms
VIN level for –40 dBm output. 25.0 29.0 33.0 dBµV
455 kHz
9-Pin 14 DC potential difference is 0 mV.
Frequency offset from 10.7 MHz when Pin
V3 = 90 dBµV drops by –3 dB.
V3 level when VB level for input of
10.7 MHz
measurement method description
Output waveform and
Min. Typ. Max.
MIN Limit
VCC=3 V, Ta=25 °C
CXA1991N
—6—
1µ
S2
CF1 : FFE1070NA
CF2 : PFB455JR
DISCRI : CDA10.7MG1
DISCRI
A1
7
Switch mode
ON
OFF
0.1µ
VB
AM IF
0.1µ
0.1µ
FE OUT
100µ
S3
8
20k
10
VD
10k 0.01µ
9
1µ
AGC
0.1µ
S1
180k
GND 1
6
FM IF
5
FM IN
4
BAND
3
AM IN
VCC
2
GND 2
B.S
1
11
12
13
14
15
16
FM RF
DET OUT
3k
CF2
33p
DISCRI
17
12µH
30p
FM MIX
18
39p
REG
19
150µH
FM OSC
20
0.01µ
AM OSC
AFC
S5
S1
CF1
BPF
100
150 43p
TUNE
V4
V3
VA
330
V2
V1
Electrical Characteristics Measurement Circuit
0.47µ
S4
10µ
A2
0.1µ
VC
CXA1991N
17
AM IN
18
FM IN
GND 1
FE OUT
0.47µ
DET OUT2 (DF)
100µ
C9
VCC
7
5
S1
FM
1µ
CF1
CF2
C7
2
AM IF
1
3
AGC
CF1 : FFE1070NA
CF2 : PFB455JR
DISCRI : CDA10.7MG1
AM
4
C8
L2
L1
BPF
Application Circuit
0.1µ
FM IF
DISCRI
BAND
0.1µ
GND 2
C10
DISCRI
6
12µH
L3
L4
OFF
S2
8
7P
C3
C2
7P
C1
0.1µ
C6
ON
C12
9
VCC
L5
C4
C5
VC
B.S
10k 0.01µ
16
FM RF
DET OUT
R4 C13
15
FM MIX
19
C11
14
REG
180k
1µ
R5
20k
13
FM OSC
R3
12
AM OSC
AFC
10
11
TUNE
20
7P
10µ
LED1
DET OUT1 (AF)
CXA1991N
Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for
any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same.
—7—
CXA1991N
FM I/O characteristics (DET OUT 1)
0
S+N
fc=100MHz
fs=1kHz, 22.5kHz dev.
VCC=3.0V
–20
–30
–4
–40
–3
N
–2
–50
–60
–10
–1
T.H.D
0
10
20
30
40
50
60
70
80
90
100
T.H.D.-Total harmonic distortion [%]
Output level ratio [dB]
–10
110
Input level [dBµV]
AM I/O characteristics (DET OUT 1)
0
S+N
fc=1660kHz
fs=1kHz, 30% mod.
VCC=3.0V
–20
–30
–4
–40
–3
N
–50
–2
–10
0
10
20
30
40
50
60
Input level [dBµV]
70
DET OUT 2 frequency response
0
Output level ratio [dB]
–10
–20
VCC=3V
fC=10.7MHz
22.5kHz dev.
VIN=80dBµV
–30
–40
–50
100
–1
T.H.D
–60
500 1k
5k 10k
fs [Hz]
—8—
50k 100k
80
90
100
110
T.H.D.-Total harmonic distortion [%]
Output level ratio [dB]
–10
CXA1991N
Coil Data
Core diameter ø 0.06 2UEW
f [MHz]
1 to 3
2. 11
AM OSC
3
4
2
1
C [pF]
1 to 3
33
Q
1 to 3
40
Number of windings [t]
1 to 3 1 to 2 2 to 3
56
14
42
Equivalent to L7BRCS-1726Y TOKO Co., Ltd.
6
S
FM OSC
φ4mm
φ0.6mm 3.5t
FM RF
φ5mm
φ0.6mm 3.5t
AM bar antenna
Core diameter ø 0.09 USTC
PRIMARY
f [kHz]
796
SECONDARY
CF1
CF2
DISCRI
VC
VC (Rear Mount)
FFE1070NA
PFB455JR
CDA10.7MG1
PVC2LXT16L
HU22124N700
PVC2LXT16B
TDK Co., Ltd.
Murata Mfg. Co., Ltd.
Murata Mfg. Co., Ltd.
Mitsumi Electric Co., Ltd.
TOKO Co., Ltd.
Mitsumi Electric Co., Ltd.
—9—
L [µH]
650
Primary Secondary
121t
22t
Q
120
CXA1991N
Notes on Operation
1.De-emphasis time constant
Time constants are determined by R4, R5 and C13. The calculation formula is as follows.
{R4 • R5/(R4 + R5)} • C13
2.FM discriminator
Quadrature detection is used for FM detection. A ceramic resonator is used in the phase shifter so that no
adjustment is required. In order to eliminate problems of distortion and offset with IF band center
frequency, the CF1 (FM • IF) and FM discrete pair combination should be of the same level.
A red
B blue
C orange
D black
E white
CF1 and Discrete fo
10.70 MHz
10.67 MHz
10.73 MHz
10.64 MHz
10.76 MHz
3.Battery save function
The battery save function operates when Pin 8 is grounded. Current consumption is 1 µA or less during
battery save. To switch from battery save mode to normal mode, Pin 8 is connected to VCC. At this time
the DET OUT (Pin 9) rise time is affected by the rise time of Pins 4, 10 and 14. For faster rise time, lower
the capacitance values of bias capacitors C5, C6 and C8, taking care that characteristics do not
deteriorate. Also, decrease or eliminate R3 and C11 time constants and control Pin 10 directly with DC
voltage of approximately 1.1 V to improve rise time.
4.Notes on pattern preparation
i) FM antenna, OSC coil configuration
Change the direction 90 degrees in order to avoid M coupling. Also, insert Pin 14 pattern between
Pins 13 and 16 and the pattern between the coils. (See "Standard Board Diagram".)
ii) Tuning circuit
The capacitance value of the tuning circuit varies according to the board; investigate the time
constants for new boards.
iii) GND pins
Pin 5 is the ground pin for IF and Pin 19 is the ground pin for FE. Use as thick a pattern as possible
for the antenna input, BPF and Pin 19 grounds, as they have a significant effect on stability and NF
characteristics.
iv) The ground point for by-pass capacitors C5 and C6 connected to Pin 14 should be as close to Pin 14
as possible.
v) When the tuning indicator is not used, connect Pin 11 to ground. This will put the tuning indicator drive
circuit into low power consumption mode and current ceases to flow to the indicator. Also, the current
consumption ICC is eliminated.
vi) Use the BPF for FM.
—10—
CXA1991N
Standard Board Diagram
Component side symbols
Solder pattern side
Component pattern side
—11—
CXA1991N
Package Outline
Unit : mm
20PIN SSOP (PLASTIC)
+ 0.2
1.25 – 0.1
∗6.5 ± 0.1
0.1
11
20
1
6.4 ± 0.2
∗4.4 ± 0.1
A
10
0.65
b
(0.15)
(0.22)
0.5 ± 0.2
0.1 ± 0.1
DETAIL B : SOLDER
b=0.22 ± 0.03
+ 0.03
0.15 – 0.01
+ 0.1
b=0.22 – 0.05
+ 0.05
0.15 – 0.02
0.13 M
DETAIL B : PALLADIUM
NOTE: Dimension “∗” does not include mold protrusion.
0° to 10°
PACKAGE STRUCTURE
DETAIL A
PACKAGE MATERIAL
EPOXY RESIN
SONY CODE
SSOP-20P-L01
LEAD TREATMENT
SOLDER / PALLADIUM
PLATING
EIAJ CODE
SSOP020-P-0044
LEAD MATERIAL
42/COPPER ALLOY
PACKAGE MASS
0.1g
JEDEC CODE
NOTE : PALLADIUM PLATING
This product uses S-PdPPF (Sony Spec.-Palladium Pre-Plated Lead Frame).
—12—