Description
The CXA2550M/N is an IC developed for compact
disc players. This IC incorporates an RF amplifier,
focus error amplifier, tracking error amplifier, APC
circuit and RF level control circuit. (The voltage-
converted optical pickup output is supported.)
Features
Low power consumption (35mW at 3.5V)
APC circuit
RF level control circuit
Both single power supply and dual power supply
operations possible.
Structure
Bipolar silicon monolithic IC
Applications
Compact disc players
Absolute Maximum Ratings (Ta = 25C)
Supply voltage
V
CC
12
V
Operating temperature Topr
20 to +75
C
Storage temperature
Tstg
65 to +150
C
Allowable power dissipation
P
D
(SOP)
620
mW
(SSOP) 370
mW
Operating Conditions
Supply voltage
V
CC
V
EE
3.0 to 4.0
V
1
CXA2550M/N
E97514B25
RF Amplifier for CD Players
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.
CXA2550M
20 pin SOP (Plastic)
CXA2550N
20 pin SSOP (Plastic)
10
15
17
20
VC
VC
10k
8k
6p
VC
VC
10k
8k
6p
4
5
2k
2k
VC
13.4k
V
CC
50
A
10k
56k
10k
V
EE
10k
55k
10k
56k
1k
V
CC
V
EE
APC LD
AMP
APC PD AMP
VREF 1.25V
V
CC
19
18
15k
VC
54k
V
EE
6k
16
VC
2k
2k
VC
13k
12p
V
EE
VC
25k
260k
260k
26k
13k
12p
VC
VC
6
7
9
32k
32k
24p
174k
13
14
24p
87k
154k
FOCUS
ERROR
AMP
30k
30k
96k
11
12
TRACKING
ERROR
AMP
15k
49
VC
V
CC
30k
30k
V
EE
2
3
1
AGCVTH
LD
PD
PD1
PD2
V
EE
F
E
EI
VC
V
CC
LD_ON
AGCCONT
(50%/30%/OFF)
RFTC
RF I
RF O
RFM
FE
FE_BIAS
TE
8
95k
VC
VC
670mV
Block Diagram and Pin Configuration (Top View)
2
CXA2550M/N
Pin Description
Pin
No.
Symbol
I/O
Equivalent circuit
Description
1
AGCVTH
--
Reference level variable pin for RF
level control.
The reference level can be varied by
the external resistor.
147
13.4k
50
10
1
2
LD
O
APC amplifier output pin.
4
5
PD1
PD2
I
I
Inversion input pin for RF I-V
amplifiers.
Connect these pins to the
photodiodes A + C and B + D
respectively. The current is supplied.
2
10k
1k
3
PD
I
APC amplifier input pin.
55k
147
3
10k
20
8
10k
4
5
100
6
V
EE
--
6
V
EE
V
EE
pin.
3
CXA2550M/N
7
8
F
E
I
I
Inversion input pin for F and E I-V
amplifiers.
Connect these pins to the
photodiodes F and E respectively.
The current is supplied.
260k
10
7
8
12p
9
EI
--
Gain adjustment pin for I-V amplifier.
11
TE
O
Tracking error amplifier output pin.
E-F signal is output.
147
260k
26k
13k
9
10
VC
O
DC voltage output pin of
(Vcc + V
EE
)/2.
Connect to GND for 1.75 power
supply; connect a smoothing
capacitor for single +3.5V power
supply.
50
200
10
120
120
16k
V
CC
V
CC
15k
V
EE
96k
300
11
Pin
No.
Symbol
I/O
Equivalent circuit
Description
4
CXA2550M/N
12
FE_BIAS
I
Bias adjustment pin for inverted side
of focus error amplifier.
164k
10
24p
32k
174k
12
13
FE
O
Focus error amplifier output pin.
15
RF O
O
RF amplifier output pin.
174k
300
13
24p
14
RFM
I
RF amplifier inverted side input pin.
RF amplifier gain is determined by
the resistor connected between this
pin and RFO pin.
2k
1m
2k
147
850
14
15
147
60k
1m
Pin
No.
Symbol
I/O
Equivalent circuit
Description
5
CXA2550M/N
16
RF I
I
The RF amplifier output RFO is input
with its capacitance coupled.
147
15k
20
16
17
RFTC
--
External time-constant pin for RF
level control.
19
LD_ON
I
APC amplifier ON/OFF switching
pin.
OFF for Vcc and ON for V
EE
.
147
50
10
17
50
18
AGCCONT
I
RF level control ON (limit level of
50%/30%)/OFF switching pin.
OFF for Vcc, 30% for open or Vc
and 50% for V
EE
.
147
50k
15
15
7
18
147
50
V
REF
19
20
V
CC
V
CC
20
Vcc pin.
Pin
No.
Symbol
I/O
Equivalent circuit
Description
6
CXA2550M/N
Electrical Characteristics
(Ta = 25
C, V
CC
= 1.75V, V
EE
=
1.75V, VC = GND)
Input GND
Input GND
Input resistance 33k
Input 1kHz 120mVp-p
Input 3MHz 120mVpp
Input resistance 33k
Input 1kHz 120mVp-p
Input 1kHz 120mVp-p
V13-4 = V13-2
V13-3
Input resistance 390k
Input 1kHz 240mVp-p
Input 1kHz 240mVp-p
V11-4 = V11-2
V11-3
LD OFF
6.37
13.23
50.0
16.7
3
1.45
--
120.0
16.4
16.4
3.0
--
1.25
50
7.3
7.3
3.0
1.25
--
830
470
1400
600
9.8
9.8
10
19.7
--
--
--
0
19.4
19.4
0
--
--
0
10.3
10.3
0
--
--
330
970
1590
--
13.23
6.37
60.0
22.7
--
--
1.25
120.0
22.4
22.4
3.0
1.25
--
50
13.3
13.3
3.0
--
1.25
170
1470
--
100
mA
mA
mV
dB
dB
V
V
mV
dB
dB
dB
V
V
mV
dB
dB
dB
V
V
mV
mV
mV
mV
12
3
4567
8
E
2
E
3
E
4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Offset voltage 1
Voltage gain
Frequency response
Maximum output amplitude H
Maximum output amplitude L
Offset voltage
Voltage gain 1
Voltage gain 2
Voltage gain difference
Maximum output amplitude L
Maximum output amplitude H
Offset voltage 1
Voltage gain 1
Voltage gain 2
Voltage gain difference
Maximum output amplitude H
Maximum output amplitude L
Output voltage 1
Output voltage 2
Output voltage 3
Maximum output amplitude
I
CC
I
EE
V15-1
V15-2
V15-3
V15-4
V15-5
V13-1
V13-2
V13-3
V13-4
V13-5
V13-6
V11-1
V11-2
V11-3
V11-4
V11-5
V11-6
V2-1
V2-2
V2-3
V2-5
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
0.8mA
450
A
570
A
0
A
0
A
300mV
300mV
300mV
300mV
1V
1V
2.7V
2.7V
2.7V
2.7V
2.0V
2.0V
0.5V
2.0V
20
6
15
15
15
15
15
13
13
13
13
13
13
11
11
11
11
11
11
2
2
2
2
RF amplifier
FE amplifier
TE amplifier
APC
Output DC measurement
Output AC measurement
Output AC measurement
Output DC measurement
Output DC measurement
Output DC measurement
Output AC measurement
Output AC measurement
Output DC measurement
Output DC measurement
Output DC measurement
Output AC measurement
Output AC measurement
Output DC measurement
Output DC measurement
Output DC measurement
Output DC measurement
Output DC measurement
Output DC measurement
I1
I2
E1
Current
consumption
No.
Measurement item
Symbol
SW conditions
Bias conditions
Measure-
ment pin
Description of I/O waveform
and measurement method
Min.
Typ.
Max.
Unit
7
CXA2550M/N
1900
1700
700
700
2.7
1.3
--
100
1322
1163
1471
1204
--
--
--
--
100
200
1900
1700
--
2.2
0.5
100
mV
mV
mV
mV
V
V
V
mV
No.
Measurement item
Symbol
SW conditions
Bias conditions
12
3
4567
8
E
2
E
3
E
4
Measure-
ment pin
Description of I/O waveform
and measurement method
Min.
Typ.
Max.
Unit
24
25
26
27
28
29
30
31
50% limit
30% limit
50% limit
30% limit
High Level
Middle Level
Low Level
V2-7
V2-8
V2-9
V2-10
V18-1
V18-2
V18-3
V10-1
O
O
O
O
O
O
O
O
O
800
A
700
A
230
A
320
A
50mV
50mV
800mV
800mV
0.5V/
2.7V
1.3V/
2.7V
0.5V/
2.7V
2.2V/
2.7V
2.0V
2.0V
2.0V
2.0V
2
2
2
2
18
18
18
10
RF level control
AGCCONT
Output DC measurement
I1
I2
E1
Center output voltage
Level control:
50%
Level control OFF
Level control:
30%
Level control OFF
Level control:
50%
Level control OFF
Level control:
30%
Level control OFF
Note)
O in the SW conditions 7 represents the OFF state.
8
CXA2550M/N
Electrical Characteristics Measurement Circuit
S1
I1
0.8mA
I2
R1
300
R2
33k
S2
R3
33k
S3
C1
33
R4
390k
S4
R5
390k
S5
S6
AC
E1
GND
GND
GND
GND
V
EE
V
EE
V
CC
V
CC
V
EE
GND
R9
5.5k
R10
10k
GND
R8
10k
GND
R7
10k
GND
R6
10k
GND
GND
S8
E2
V
EE
R11
1M
C2
0.1
V
EE
E3
V
EE
E4
V
EE
C3
33
GND
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
1
V
CC
AGCVTH
LD_ON
LD
AGCCONT
PD
RFTC
PD1
RF I
PD2
RF O
V
EE
RFM
F
FE
E
FE_BIAS
EI
TE
VC
S7
9
CXA2550M/N
Description of Functions
RF Amplifier
The photodiode current input to the input pins (PD1, PD2) are current-to-voltage (I-V) converted by the
equivalent resistance of 58k
at PD I-V amplifiers, respectively. The signal is added by the RF summing
amplifier and then the I-V converted output voltage of the photodiode (A + B + C + D) is output to RFO pin.
This pin is used check the eye pattern.
The frequency response of the RF output signal can be equalized by adding the capacitance (Cp) to RFI pin.
The low frequency component of the RFO output voltage is as follows;
V
RFO
= 2.75
(V
A
+ V
B
)
= 159.5k
(iPD1 + iPD2)
Focus Error Amplifier
The difference between the RF I-V amplifier output VA and VB is obtained and the I-V converted voltage of the
photodiode (A + C B D) is output.
The FE output voltage (low frequency) is as follows;
V
FE
= 5.4
(V
A
V
B
)
= (iPD2 iPD1)
315k
GND
33k
4
15
I-V
PD1
58k
2k
VA
PD1 IV AMP
33k
I-V
PD2
58k
2k
VB
PD2 IV AMP
5
RF SUMMING AMP
5.5k
14
RFM
RFO
Cp
V
CC
12
13
174k
24p
164k
32k
32k
87k
24p
V
EE
47k
FE
FE BIAS
VB
VA
(B + D)
(A + C)
10
CXA2550M/N
Tracking Error Amplifier
Each signal current from the photodiodes E and F is I-V converted and input to Pins 7 and 8 via a resistor
which determines the gain. The signal is amplified by the gain amplifier, operated by the tracking error
amplifier and then the (F-E) signal is output to Pin 11.
The balance adjustment is performed by varying the combined resistance value of the feedback resistors,
which are T type-configured at the E I-V amplifier, by using the external resistance value of EI pin.
F I-V amplifier feedback resistance value = R
F1
+ R
F2
+ = 403k
E I-V amplifier feedback resistance value = (R
E1
// R
1
) + R
E2
+
Leave EI pin open when the balance adjustment is not executed in this IC.
The gain for F I-V and E I-V amplifiers becomes the same when EI pin is left open.
11
I-V
F
R
F1
260k
30k
I-V
E
7
8
12p
R
F3
26k
R
F2
13k
96k
96k
R
E1
260k
12p
R
E2
13k
R
E3
26k
9
TE
30k
EI
22k
4.7k
270k
R
1
R
2
220k
220k
R
F1
R
F2
R
F3
(R
E1
// R
1
)
R
E2
(R
E3
// R
2
)
11
CXA2550M/N
Center Voltage Generation Circuit
This circuit provides the center potential when this IC is used at single power supply. The maximum current is
approximately 3mA. The output impedance is approximately 50
.
APC & Laser Power Control
APC
When the laser diode is driven by a constant current, the optical power output has extremely large negative
temperature characteristics. The APC circuit is used to maintain the optical power output at a constant level.
The laser diode current is controlled according to the monitor photo diode output.
APC is set to ON by connecting the LD_ON pin to V
CC
; OFF by connecting it to V
CC
.
VR
10
30k
30k
V
EE
V
CC
50
15
16
1
V
EE
V
CC
LD
R1
22
C2
100
L1
10H
LD
PD
C1
1
GND
R3
100
R2
500
PD
R4
10k
R5
55k
R8
10k
V
EE
130mV
R10
56k
V
CC
R11
10k
R12
56k
R6
1k
V
EE
VREF
R14
12.5k
2
3
50
R15
13.4k
R9
54k
V
EE
C3
0.01
RF I
RF O
1.1Vp-p
R7
6k
RF
670mV
17
V
EE
V
EE
AGCVTH
RFTC
C4
1
R13
1M
AGCCONT
MICRO-
COMPUTER
LD_ON
MICRO-
COMPUTER
18
19
V
L
12
CXA2550M/N
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.
Application Circuit
For single power supply +3.5V
For dual power supply 1.75V
10
15
17
20
4
5
19
18
16
6
7
9
13
14
11
12
2
3
1
AGCVTH
LD
PD
PD1
PD2
V
EE
F
E
EI
VC
V
CC
LD_ON
AGCCONT
RFTC
RF I
RF O
RFM
FE
FE_BIAS
TE
8
FOCUS
BIAS
I_V
TRK E
GAIN
I_V
I_V
I_V
SSP
GND
47k
V
CC
SSP
SSP
R9
5.5k
0.01
GND
C3
0.1
R11
1M
MICRO-
COMPUTER
MICRO-
COMPUTER
+3.5V
V
CC
33/6.3V
GND
VC
R5
270k
22k
R5
4.7k
VC
GND
R5
220k
E
F
R4
220k
GND
VC
33
/6.3V
R3
33k
R2
33k
A
B
C
D
PD
500
100
LD
1
/6.3V
10H
11
100/6.3V
V
CC
GND
AGCVTH
LD
PD
PD1
PD2
V
EE
F
E
EI
VC
V
CC
LD_ON
AGCCONT
RFTC
RF I
RF O
RFM
FE
FE_BIAS
TE
FOCUS
BIAS
I_V
TRK E
GAIN
I_V
I_V
I_V
SSP
V
EE
47k
V
CC
SSP
SSP
R9
5.5k
0.01
V
EE
C3
0.1
R11
1M
MICRO-
COMPUTER
MICRO-
COMPUTER
+1.75V
V
CC
33/6.3V
GND
R5
270k
22k
R5
4.7k
GND
R5
220k
E
F
R4
220k
V
EE
33
/6.3V
R3
33k
R2
33k
A
B
C
D
PD
500
100
LD
1
/6.3V
10H
11
100/6.3V
V
CC
GND
GND
GND
V
EE
GND
10
15
17
20
4
5
19
18
16
6
7
9
13
14
11
12
2
3
1
8
13
CXA2550M/N
LASER POWER CONTROL (LPC)
The RF level is stabilized by attaching an offset to the APC V
L
and controlling the laser power in sync with the
RF level fluctuations.
The RF O and RF I levels are compared and the larger of the two is smoothed by the RFTC's external CR.
This signal is then compared with the reference level.
The laser power is controlled by attaching an offset to V
L
according to the results of comparison with the
reference level.
Set the reference level to 670mV. (center voltage reference)
When the reference level is changed, connect the external resistor to the AGCVTH pin (Pin 1). The reference
level can be lowered by connecting the resistor between Pin 1 and the center output voltage or between Pin
20 and V
CC
.
The AGCCONT pin (pin 18) is used to switch the level of the laser power control circuit; OFF, ON (laser power
limit of 30%) and ON (laser power limit of 50%)
Note) For the laser power limit, 50% is recommended for PD IC; 30% for LC.
Notes on Operation
1. Power supply
The CXA2550M/N can be used either at dual power supply or single power supply. The table below shows the
connection of power supply for each case.
2. RF amplifier
In this circuit, the IC internal phase compensation value is set so as to support the voltage output-type pickup.
Therefore, when the current output-type pickup is used, the capacitance of optical pickup and leads etc. are
attached to PD1 and PD2 pins and oscillation may occur.
3. laser power control
The RF level is stabilized by attaching an offset to the APC V
L
and controlling the laser power in sync with the
RF level fluctuations. Therefore, use this circuit in the state where the focus servo is applied.
The laser life is shortened by increasing the laser power when the less light is reflected from the disc. It is
recommended that the typical laser power value is set lower to maintain the laser life.
Take care of the laser maximum ratings when using the laser power control circuit.
AGCCONT
H (V
CC
)
M (VC or OPEN)
L (V
EE
)
LPC
OFF
ON
ON
LPC limit
--
30%
50%
V
L
variable range
Approximately 1.27V
Approximately 1.27V 350mV
Approximately 1.27V 570mV
Dual power supply
Single power supply
V
CC
+power supply
Power supply
V
EE
power supply
GND
VC
GND
OPEN
14
CXA2550M/N
Package Outline
Unit: mm
CXA2550M
SONY CODE
EIAJ CODE
JEDEC CODE
SOP-20P-L01
SOP020-P-0300-A
PACKAGE STRUCTURE
PACKAGE MATERIAL
LEAD TREATMENT
LEAD MATERIAL
PACKAGE WEIGHT
COPPER ALLOY
SOLDER PLATING
EPOXY / PHENOL RESIN
0.3g
20PIN SOP (PLASTIC) 300mil
12.45 0.1
+ 0.4
20
11
0.45 0.1
1.27
10
1
5.3
0.1
+ 0.3
7.9
0.4
6.9
0.2 0.05
+ 0.1
0.5
0.2
0.1 0.05
+ 0.2
1.85 0.15
+ 0.4
0.15
0.12
M
LEAD PLATING SPECIFICATIONS
ITEM
LEAD MATERIAL
COPPER ALLOY
SOLDER COMPOSITION
Sn-Bi Bi:1-4wt%
PLATING THICKNESS
5-18
m
SPEC.
SCT Ass'y
SONY CODE
EIAJ CODE
JEDEC CODE
SOP-20P-L01
SOP020-P-0300-A
PACKAGE STRUCTURE
PACKAGE MATERIAL
LEAD TREATMENT
LEAD MATERIAL
PACKAGE WEIGHT
COPPER ALLOY
SOLDER PLATING
EPOXY / PHENOL RESIN
0.3g
20PIN SOP (PLASTIC) 300mil
12.45 0.1
+ 0.4
20
11
0.45 0.1
1.27
10
1
5.3
0.1
+ 0.3
7.9
0.4
6.9
0.2 0.05
+ 0.1
0.5
0.2
0.1 0.05
+ 0.2
1.85 0.15
+ 0.4
0.15
0.12
M
15
CXA2550M/N
Package Outline
Unit: mm
CXA2550N
20PIN SSOP (PLASTIC)
SONY CODE
EIAJ CODE
JEDEC CODE
PACKAGE STRUCTURE
PACKAGE MATERIAL
LEAD TREATMENT
LEAD MATERIAL
PACKAGE MASS
EPOXY RESIN
PALLADIUM PLATING
COPPER ALLOY
0.1g
SSOP-20P-L01
SSOP020-P-0044
0.1
0.1
0.5
0.2
0 to 10
DETAIL A
NOTE: Dimension "
" does not include mold protrusion.
0.15 0.01
DETAIL B : PALLADIUM
+ 0.03
b=0.22
0.03
6.5
0.1
4.4
0.1
0.65
20
11
10
1
A
0.1
1.25 0.1
+ 0.2
6.4
0.2
0.13 M
b
Sony Corporation
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