SONY CXA2500

CXA2500M/N
Dual REC/PB Preamplifier
Description
The CXA2500M/N is a dual recording/playback preamplifier system bipolar IC which has been developed
for the low voltage operating cassette tape recorder.
CXA2500M
24 pin SOP (Plastic)
Features
• Low quiescent current (VCC = 2V)
PB: ICC = 3.2mA (typ.)
REC: ICC = 5.2mA (typ.)
• Very few external parts
• Built-in Metal/Normal selection switch
• Small switching noise due to internal transient
muting
CXA2500N
24 pin SSOP (Plastic)
Absolute Maximum Ratings (Ta = 25°C)
• Supply voltage
VCC
7
• Operating temperature Topr
–20 to +75
• Storage temperature
Tstg –65 to +150
• Allowable power dissipation PD
Applications
3V headphone radio cassette recorders
CXA2500M
CXA2500N
Structure
Bipolar silicon monolithic IC
600
470
Operating Conditions
Supply voltage PB
REC
MIC INPUT (B)
PB PRE
INPUT (B)
PB NF (B)
PB OUTPUT (A)
PB EQ
SWITCH (B)
TUNER
INPUT (B)
LINE
OUTPUT (B)
REC DRIVE
INPUT (B)
REC DRIVE
OUTPUT (B)
VCC
PB/REC
SELECTOR
24
23
22
21
20
19
18
17
16
15
14
13
PB
GCA
MIC
V
V
PB/
REC
REC
LINE
mW
mW
1.2 to 3.5
1.6 to 3.5
GROUND
Bock Diagram
VCC
VCC
V
°C
°C
AMP
AGC
NORM/
METAL
AGC
DET
REF
AMP
LINE
12dB
PB
6
PB PRE
INPUT (A)
PB NF (A)
PB OUTPUT (A)
PB EQ
SWITCH (A)
7
8
9
10
11
12
TAPE/TUNER
SELECTOR
5
AGC TIME
CONSTANT
4
REC DRIVE
OUTPUT (A)
3
REC DRIVE
INPUT (A)
2
20.5dB
LINE
OUTPUT (A)
1
TAPE/
TUNER
REC
–0.3dB
MIC INPUT (A)
22dB
REFERENCE
6dB
GCA
TUNER
INPUT (A)
MIC
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–
E94806B8Y
CXA2500M/N
Pin Description
No.
Symbol
Pin voltage is during VCC = 2V
Voltage
(Typ.)
Equivalent circuit
Description
VCC
2
23
MIC IN (A)
MIC IN (B)
0.93V
510
2
20k
MIC preamplifier input
23
10k
20k
Vref
VCC
3
22
PB PRE IN (A)
PB PRE IN (B)
510
0.93V
Vref
22
PB preamplifier input
3
VCC
4
21
PB-NF (A)
PB-NF (B)
0.93V
510
510
Vref
21
PB equalizer circuit negative
feedback
4
VCC
5
20
PB OUT (A)
PB OUT (B)
0.93V
20
PB preamplifier output
5
VCC
6
19
PB EQ SW (A)
PB EQ SW (B)
0.93V
19
6
–2–
PB equalizer switch
CXA2500M/N
No.
Symbol
Voltage
(Typ.)
Equivalent circuit
Description
VCC
40k
7
18
TUNER IN (A)
TUNER IN (B)
0.93V
40k
Tuner input
18
7
4k
Vref
VCC
8
17
LINE OUT (A)
LINE OUT (B)
40k
142
17
0.58V
Line amplifier output
8
VCC
9
16
REC AMP IN (A)
REC AMP IN (B)
0.93V
REC drive input
16
9
10k
4k
Vref
VCC
10
15
REC AMP OUT
(A)
REC AMP OUT
(B)
15
1.0V
10
REC drive output
VCC
1
REF
1
0.93V
–3–
Reference voltage output
CXA2500M/N
No.
Symbol
Voltage
(Typ.)
Equivalent circuit
Description
VCC
11
AGC TC
1k
0.37V
AGC time constant
11
VCC
150k
142
12
TAPE/TUNER
0.5V
(Open)
12
50k
Tape/tuner selection
During Tape/Normal: 0V
During Tape/Metal: 0.5V
During Tuner Mode: 2.0V
VCC
142
13
PB/REC
0V
(2.0V)
13
–4–
PB/REC selection
During PB = 0V
During REC = 2.0V
Icq1
Icq2
Icq3
Icq4
Vref
Tape playback
quiescent current
MIC recording
quiescent current
Radio playback
quiescent current
Radio pecording
quiescent current
Reference
voltage
S3
–5–
A
B
B
B
B
OFF OFF
A
OFF
C
PB
ON
B
Ripple rejection RR
A
A
A
A
A
A
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
ON
ON
ON
ON
ON
OFF OFF
ON
ON
ON
ON
ON
A
A
A
A
A
A
OFF
OFF
OFF
OFF
OFF
OFF
C
C
C
C
B
C
PB
PB
PB
PB
PB
PB
ON
ON
ON
ON
ON
ON
A
A
A
A
A
A
Vno
A
Output noise
voltage
B
A
A
A
A
Vom
B
B
B
B
B
A
Maximum output
voltage
A
B
B
B
B
B
THD
A
B
B
B
B
B
Total harmonic
distortion
ON
B
B
B
B
B
CB
ON
OFF OFF
OFF OFF
OFF OFF
OFF OFF
B
S9
Channel
balance
A
A
S8
OFF OFF
S7
Gvc2
OFF
OFF
A
A
A
A
S6
Close loop
voltage gain 2
C
C
OFF
OFF
OFF
OFF
S5
Gvc1
PB
PB
A
A
C
C
S4
Close loop
voltage gain 1
ON
ON
OFF REC
OFF PB
OFF REC
OFF PB
S2
V1
Io
Io
Io
Io
2.8
4.2
1.3
Vcc = 2.0V
No signal, Tuner
Vcc = 2.0V
2.8
No signal, Tuner Rec
e8, e17
fr = 100Hz
Vr = –30dBm
e8, e17 Rg = 2.2kΩ
e8, e17 THD = 1%
dBm e8, e17 Vo = –15dBm
dBm e8, e17 Vo = –15dBm
dBm e8, e17 Vo = –15dBm
dBm e8, e17 Vo = –15dBm
6.2
4.7
7.2
5.5
65
—
72
27.5 35
—
+2.0
—
125
—
0.3 1.05
0
190 300
—
–2.0
25.5 27.2 29.0
28.5 30.8 33.0
54
0.78 0.93 1.05
5.2
Vcc = 2.0V
3.8
No signal, Mic Rec
Vcc = 2.0V
No signal, Tape
3.2
dB
µV
mV
%
dB
V
mA
Min. Typ. Max. Unit
1.8
Vcc = 2.0V
No signal, Tape
dBm e8, e17 Vo = –15dBm
Input condition
Measurement
conditions
VCC = 2.0V, f = 1kHz, Ta = 25°C, unless otherwise specified.
Measure
-ment
S10 S11 S12 S13 Vin1 Vin2 Vin3 Unit point
Gvo
A
A
A
A
A
A
S1
SW condition
Open loop
voltage gain
(1) PLAYBACK MODE
Symbol
Item
Electrical Characteristics
CXA2500M/N
Symbol
S1
–50
A
B
B
B
B
OFF OFF
A
OFF
A
ON REC
B
Ripple rejection RR
–6–
Vo ALC
CB ALC
ALC voltage
ALC balance
Ripple rejection RR
W ALC
ALC width
B
A
A
A
A
Vno
Output noise
voltage
A
A
CB
Channel
balance
Total harmonic
THD
distortion
Gvc
Voltage gain
(3) MIC RECORDING: -
A
A
B
B
B
B
A
B
B
B
B
OFF OFF
A
OFF
C
ON REC
–60
A
B
B
B
B
OFF OFF
B
ON
C
ON REC
–2
–5
fr = 100Hz
Vr = –30dBm
e10, e15
—
4.7
4.5
1.5
dB
mV
%
dB
dB
µV
mV
%
dB
3
0
—
+2
dB
230 340 470 mV
dBm e10, e15 Vin = –60dBm
dBm e10, e15 Vin = –60dBm
–60
A
B
B
B
OFF OFF
B
ON
C
ON REC
—
B
B
B
OFF OFF
B
ON
C
ON REC
39
1.5
0
A
—
–1.5
B
B
B
B
—
58.5 61.8 65.0
B
dBm e10, e15 Vin = –50dBm
dBm e10, e15 Vo = –15dBm
dBm e10, e15 Vo = –15dBm
33
The input range
when the output
level varies ±3dB
e10, e15
from the standard
input level
(Vin = –60dBm)
A
C
C
24
—
280 360
3
B
B
B
fr = 100Hz
Vr = –30dBm
—
380 600
e10, e15 BW = 30 to 20kHz —
B
B
B
e10, e15
e10, e15 Rg = 10kΩ
e10, e15 THD = 1%
A
B
B
B
A
0.1
B
B
B
B
OFF OFF
OFF OFF
OFF OFF
OFF OFF
A
B
B
B
OFF
ON
ON
ON
C
C
C
C
ON REC
ON REC
ON REC
ON REC
A
—
0.5
OFF OFF
A
–30 dBm e10, e15 Vin = –30dBm
A
B
A
OFF
B
A
A
OFF OFF
A
ON REC
A
B
A
OFF
B
Vno
A
OFF OFF
Output noise
voltage
ON REC
A
A
OFF
Maximum output
Vom
voltage
A
A
THD
Total harmonic
distortion
ON REC
1.5
0
–30 dBm e10, e15 Vin = –30dBm
A
A
A
B
B
OFF OFF
A
OFF
A
ON REC
A
Channel balance CB
–1.5
17.8 19.5 21.2
–30 dBm e10, e15 Vin = –30dBm
A
A
Voltage gain
A
Min. Typ. Max. Unit
B
S9
B
S8
OFF OFF
S7
A
S6
OFF
S5
A
S4
Measurement
conditions
ON REC
S3
Measure
-ment
S10 S11 S12 S13 Vin1 Vin2 Vin3 Unit point
Input condition
A
S2
SW condition
Gvc
(2) RADIO RECORDING: -
Item
CXA2500M/N
V1
S5
1kHz
Vin1
1µ
0.01µ
1kHz
Vin2
S7
2
1
3
2.2k
33µ
330
4
S9
A
B
100k
15k
1kHz
Vin3
22k
S11
A
10k 10k
B
1µ
7
6
5
13
14
15
16
1µ
8
e8
B
I11
11
S13
C
A
400 to 30kHz
BPF
4.7µ
10
0.0047µ
10k
400 to 30kHz
BPF
9
2.2k
e10
S4
12
VCC
2V
Vr
2V
A TUNER
B METAL PB
C NORMAL PB
VCC
PB
S3 REC
10k
17
I0
A
47µ B
18
S2
19
1µ
1µ
10k
0.0047µ
20
1µ
1µ
21
22k
B
22
1µ
15k
A
S12
S1
23
100k
S10 B
Vin3
10k 10k
GND
REF
100µ
1µ
2.2k
A
1kHz
e15
24
1µ
0.01µ
Vin2
S8
330
400 to 30kHz
BPF
MIC
IN (B)
MIC
IN (A)
S6
Vin1
1kHz
e17
PB PRE
IN (B)
1kHz
33µ
400 to 30kHz
BPF
PB/MIC
NF (B)
PB PRE
IN (A)
PB
OUT (B)
PB/MIC
NF (A)
METAL
SW (B)
PB
OUT (A)
TUNER
IN (B)
METAL
SW (A)
–7–
TUNER
IN (A)
LINE
OUT (B)
LINE
OUT (A)
REC
IN (B)
REC
IN (A)
REC
OUT (B)
REC
OUT (A)
VCC
AGC TC
REC/PB
SW
TAPE/
RADIO SW
Measurement Circuit
CXA2500M/N
100µ
Application Circuit
BIAS
1
24
–8–
PB
REC
0.01µ
23
3
5
20
6
19
12dB
AMP
AMP
22k
17
1µ
0.01µ
8
–0.3dB
LINE
LINE
RADIO IN (A)
22k
7
18
0.01µ
1µ
RADIO IN (B)
1µ
1µ
REF
1µ
1µ
0.0047µ
10k
10
20.5dB
REC
REC
15
11
14
47µ
3.3M
AGC
DET
TO POWER AMP (A)
9
16
10k
0.0047µ
TO POWER AMP (B)
47µ
13
10k
12
22µ
22µ
VCC
TAPE/NORM
TAPE/METAL
RADIO
2.2k
TAPE/
RADIO
NORM/
METAL
PB/
REC
PB
REC
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.
39k
33µ
15k
330k
PB
PB
330k
0.01µ
4
21
15k
330
0.01µ
39k
1000p
330
22dB
GCA
AGC
GCA
A CH
33µ
1000p
22
0.01µ
MIC IN (A)
1µ
2
6dB
MIC
MIC
1µ
MIC IN (B)
CXA2500M/N
CXA2500M/N
Description of Operation
REF Pin (Pin 1)
A low impedance pin for outputting the internal reference voltage, which is fixed at 0.93V regardless of
supply voltage variation.
LINE OUT Pin (Pin 8)
This output pin outputs signal from any selected source (MIC, Tape or Tuner) to the subsequent stages
such as Dolby NR or power amplifier for further signal processing. It is internally biased at 0.58V so as to
achieve maximum dynamic swing at minimum supply voltage of 1.2V. The change of DC potential at this
pin that may result from any changeover of PB/REC or Tape/Tuner switch was set to be minimum, thus
reducing any potential occurence of switching noise.
REC Out Pin (Pin 10)
This recording driver output pin is internally biased at 1.0V to achieve maximum signal swing at minimum
supply voltage of 1.6V during the recording mode. The REC OUT will be momentally muted during the
changeover of PB/REC or Tape/Tuner modes, so as to prevent mis-recording of any undesired switching
noise. The muting period is determined by the values of R and C at Pins 12 or 13.
AGC TC Pin (Pin 11)
This is the external pin for AGC filter during the MIC Recording mode. The attack time is determined by the
1kΩ resistor inside the IC and the external electrolytic capacitor. The recovery time is determined by both
external resistor and electrolytic capacitor at Pin 11.
Notes on Operation
1. The following table shows the potential at Pins 12 and 13 and the associated operating states of the
amplifier. Each of the pins, when at the same potential as Pin 14, has H level, and when at the same
potential as Pin 24, has L level.
System Control Operation Table
Control pins
Pin 13
L
H
Pin 12
L
FLOAT
H
L, FLOAT
H
Operating
mode
Playback
(Normal)
Playback
(Metal)
Tuner
Mode
MIC
Recording
Tuner
Recording
MIC AMP
OFF
OFF
OFF
ON
OFF
AGC DET
OFF
OFF
OFF
ON
OFF
GCA
OFF
OFF
OFF
ON
OFF
AMP
OFF
OFF
OFF
ON
OFF
PB AMP
ON
ON
OFF
OFF
OFF
EQ SWITCH
OFF
ON
OFF
OFF
OFF
LINE AMP
ON
ON
ON
ON
ON
REC AMP
OFF
OFF
OFF
ON
ON
Amplifier operating state
–9–
CXA2500M/N
2. PB Mode:
To reduce the PB amplifier DC output offset, it is recommended that 39kΩ resistor be connected as shown
in the Application Circuit. However, too low this resistor value may affect the low frequency portion of the
PB frequency response. The inter-relationship of the RC values in the playback equalization network is as
shown below:
55 GV (dB)
+
PB
–
R1
330k
R5
330
C1
0.01µ
CXA2500
TAPE PB: GV, THD vs f
VO = –15dBm
VCC = 2V
50
R2
15k
Voltage [dB]
IN
R3
22k
45
40
35
NORMAL
30
G1
G2
25
METAL
REF
C2
33µ
R4
39k
10
100
1kf1 f2
10k
100k
f [Hz]
During Normal PB mode,
Gain G1 = 20 log (R2 + R5)/R5
3dB cut-off frequency, f1 = 1/(2 × 3.1416 × C1 × R2)
During Metal PB mode,
Gain G2 = 20 log (R2//R3 + R5)/R5
3dB cut-off frequency, f2 = 1/(2 × 3.1416 × C1 × R2//R3)
3. Use of RC at Tape/Tuner and PB/REC pins:
The purpose of the external RC components at the switch inputs is to create an internal mute pulse so as to
mute the REC OUT momentally during the switching operation. By doing so, the switching click noise that
may appear at REC OUT can be reduced. The selection of the RC values affects the duration of the mute
pulse. It is recommended to use resistor of 2.2kΩ and below at Tape/Tuner pin, i.e Pin 12. These RC
components may be removed if such internal pop noise countermeasure is not required.
– 10 –
CXA2500M/N
Package Outline
Unit: mm
CXA2500M
24PIN SOP (PLASTIC)
+ 0.4
15.0 – 0.1
+ 0.4
1.85 – 0.15
24
13
6.9
12
0.45 ± 0.1
+ 0.1
0.2 – 0.05
1.27
0.5 ± 0.2
1
+ 0.2
0.1 – 0.05
7.9 ± 0.4
+ 0.3
5.3 – 0.1
0.15
± 0.12 M
PACKAGE STRUCTURE
SONY CODE
SOP-24P-L01
EIAJ CODE
∗SOP024-P-0300-A
JEDEC CODE
CXA2500N
MOLDING COMPOUND
EPOXY/PHENOL RESIN
LEAD TREATMENT
SOLDER PLATING
LEAD MATERIAL
COPPER ALLOY / 42ALLOY
PACKAGE WEIGHT
0.3g
24PIN SSOP(PLASTIC)
+ 0.2
1.25 – 0.1
∗7.8 ± 0.1
0.1
24
13
∗5.6 ± 0.1
7.6 ± 0.2
A
1
12
b
0.13 M
0.5 ± 0.2
(0.15)
(0.22)
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
0.65
B
DETAIL B : PALLADIUM
0° to 10°
NOTE: Dimension “∗” does not include mold protrusion.
DETAIL A
PACKAGE STRUCTURE
PACKAGE MATERIAL
EPOXY RESIN
SONY CODE
SSOP-24P-L01
LEAD TREATMENT
SOLDER/PALLADIUM
PLATING
EIAJ CODE
SSOP024-P-0056
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).
– 11 –