FAN7031MTFX [FAIRCHILD]
Audio Amplifier, PDSO20,;
| 型号： | FAN7031MTFX |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | Audio Amplifier, PDSO20, 放大器 光电二极管 商用集成电路 |
| 文件： | 总20页 (文件大小：472K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
www.fairchildsemi.com
FAN7031
2W Stereo Power Amplifier with Four Selectable
Gain Setting and Headphone Drive
Features
Description
• 1.85W
and 2.45W
Power Per Each Channel Into
RMS
The FAN7031 is a dual fully differential power amplifier in a
20-pin TSSOP-EP thermally enhanced package. When
delivering 1.85W of continuous RMS power into 4Ω speaker
at 5V supply, the FAN7031 has less than 1% of THD+N over
the entire audible frequency range, 20Hz to 20kHz. To save
power consumption in the portable applications, the
FAN7031 provides shutdown function. Setting the shutdown
pin to ground level, the FAN7031 falls into shutdown mode
and consumes less than 4µA over all supply voltage range,
2.7V to 5.5V. Two gain setting pins(G0 and G1) control the
gain of the FAN7031. The gain is selectable to 6dB, 10dB,
15.6dB and 21.6dB. The FAN7031 provides the single-
RMS
4Ω Load With Less Than 1% and 10% THD+N,
Respectively
• Selectable Gain Via Internal Gain Control Circuit Which
Eliminates External Gain Setting Resistors : 6dB, 10.3dB,
15.6dB, 21.6dB(Select)
• Low Quiescent Current : Typical 5.5mA@5V
• Low Shutdown Current : Typical 0.04µA@5V
• Fully Differential Input, Which Immunes the Common
Mode Noise
• Stereo Headphone Drive
• Active Low Shutdown Logic
• Guaranteed Stability Under No Load Condition
• Thermally Enhanced Surface-Mount 20TSSOP-EP
Package
ended(SE) operation by setting SE/BTL pin to above V /2.
DD
Using SE/BTL pin and a mechanical switch which provides
at the headphone jack, SE mode and BTL mode are automat-
ically determined. Additional components such as resistors
for gain setting and bootstrap capacitors are not needed,
making the FAN7031 well suited for portable sound systems
and other hand-held sound equipment. Target applications
include notebook and desktop computers and portable audio
equipment.
20-TSSOP-EP
1
Rev. 1.0.1
©2003 Fairchild Semiconductor Corporation
FAN7031
Internal Block Diagram
RIN-
ROUT+
RIN+
ROUT-
CONTROL
BIAS
G0
G1
SE/BTL
TSD
VDD/2
BYPASS
Gain Control
SE/BTL
Control
Current
Source
SD
LIN-
LOUT+
LOUT-
LIN+
2
FAN7031
Pin Assignments
GND
G0
G1
LOUT+
LIN-
PVDD2
RIN+
LOUT-
LIN+
BYPASS
1
20
GND
SD
ROUT+
RIN-
VDD
PVDD1
ROUT-
NC
SE/BTL
GND
Heat Sink
10
11
Pin Description
Pin No
Symbol
I/O
Decription
1*
2
3
4
5
GND
G0
G1
LOUT+
LIN-
-
I
I
O
I
Ground
Gain Selection Input(MSB)
Gain Selection Input(LSB)
Left Channel (+) Output
Left Channel (-) Input
6**
7
8
9
10
11*
PVDD2
RIN+
LOUT-
LIN+
BYPASS
GND
I
I
O
I
O
-
Left Channel Power Supply Voltage
Right Channel (+) Input
Left Channel (-) Output
Left Channel (+) Input
Bypass Capacitor Connect
Ground
Single-Ended & BTL Selection:
GND ≤ SE/BTL ≤ VDD/2:BTL Mode
VDD/2 < SE/BTL ≤ VDD: SE Mode
12
SE/BTL
I
13
14
15**
16**
17
NC
-
O
I
I
I
No Connection
ROUT-
PVDD1
VDD
RIN-
ROUT+
Right Channel (-) Output
Right Channel Power Supply Voltage
Power Supply Voltage
Right Channel (-) Input
Right Channel (+) Output
18
O
Shutdown Logic Low
19
SD
I
SD=VDD: Chip Enable
SD=GND: Chip Shutdown
20*
GND
-
Ground
* All GND is internally tied together.
** For the best performance, VDD, PVDD1 and PVDD2 must be the same voltage level(strongly recommend).
3
FAN7031
Absolute Maximum Ratings
Parameter
Maximum Supply Voltage
Power Dissipation
Operating Temperature
Storage Temperature
Junction Temperature
Symbol
VDDmax
Value
6.0V
Internally Limited
-40 ~ +85
-65 ~ +150
150
Unit
V
W
°C
°C
°C
Remark
P
D
See Derating Curve
T
OPG
T
STG
T
J
30.4
112.5
Multi Layer Board
Single Layer Board
Thermal Resistance
(Junction to Ambient)
Rthja
°C/W
ESD Rating (Human Body Model)
2000
V
Note1 : Rthja was derived using a JEDEC multi layer and single layer.
Operating Ratings
Parameter
Symbol
Min
Typ
Max
Unit
Power Supply Voltage
V
DD
2.7
-
5.5
V
4
FAN7031
Electrical Characteristics
(V
DD
= 5.0V, Ta = 25°C, unless otherwise specified)
Parameter
Symbol
Conditions
RL=4Ω, Av=6dB
No Input, No Load
SD = GND
THD+N =1%, RL = 4Ω, f = 1kHz
THD+N =10%, RL = 4Ω, f = 1kHz
Min. Typ. Max. Unit
Offset Voltage
Supply Current
Shutdown Current
V
OFF
-25
-
25
10
4
mV
mA
µA
W
I
-
-
-
-
5.5
DD
I
0.04
1.85
2.45
SD
-
Output Power
P
O
-
W
SE/BTL=GND, G0=GND, G1=GND,
Vin=4Vpp, No Load
SE/BTL=GND, G0=GND, G1=VDD,
Vin=2.44Vpp, No Load
SE/BTL=GND, G0=VDD, G1=GND,
Vin=1.34Vpp, No Load
SE/BTL=GND, G0=VDD, G1=VDD,
Vin=0.66Vpp, No Load
-
-
-
-
6
-
-
-
-
dB
dB
dB
dB
10.3
15.6
21.3
BTL Mode Gain
SE Mode Gain
Av
SE/BTL=VDD,
-
-
4.3
0.2
70
-
0.75
-
dB
%
Vin=2.44Vpp, No Load
Total Harmonic Distortion + Noise THD+N
Power Supply Rejection Ratio PSRR
P = 1W, RL=4Ω, f = 20kHz
O
C
= 0.47µF, RL=4Ω, BTL Mode,
byp
40
dB
∆VDD=500mVpp, f = 1kHz
Electrical Characteristics (Continued)
(V
DD
= 3.3 V, Ta = 25°C, unless otherwise specified)
Parameter
Symbol
Conditions
RL=4Ω, Av=6dB
No Input, No Load
SD = GND
THD+N =10%, RL = 4Ω, f=1kHz
Min. Typ. Max. Unit
Offset Voltage
Supply Current
Shutdown Current
Output Power
V
OFF
-25
-
25
8
4
mV
mA
µA
W
I
-
-
-
-
4.3
DD
I
0.08
1.02
0.2
SD
P
O
-
Total Harmonic Distortion + Noise THD+N
P
= 0.5W, RL = 4Ω, f = 20kHz
0.75
%
O
C
= 0.47µF, RL=4Ω, BTL Mode,
byp
Power Supply Rejection Ratio PSRR
40
70
-
dB
∆VDD=330mVpp, f = 1kHz
Electrical Characteristics (Continued)
(V
DD
= 2.7 V, Ta = 25°C, unless otherwise specified)
Parameter
Symbol
Conditions
RL=4Ω, Av=6dB
No Input, No Load
SD = GND
THD+N =10%, RL = 4Ω, f=1kHz
Min. Typ. Max. Unit
Offset Voltage
Supply Current
Shutdown Current
Output Power
V
OFF
-25
-
25
7
4
mV
mA
µA
W
I
-
-
-
-
4.1
DD
I
0.04
0.54
0.2
SD
P
O
-
Total Harmonic Distortion + Noise THD+N
P
= 0.25W, RL = 4Ω, f = 20kHz
0.75
%
O
C
= 0.47µF, RL=4Ω, BTL Mode,
byp
Power Supply Rejection Ratio PSRR
-
65
-
dB
∆VDD=270mVpp, f = 1kHz
5
FAN7031
Performance Characteristics
10
5
10
5
BTL mode
VDD=5V
RL=8ohm
Av=6dB
2
1
2
1
20kHz
0.5
0.5
20kHz
0.2
0.2
0.1
1kHz
0.1
1kHz
0.05
0.05
0.02
0.01
20Hz
0.02
0.01
20Hz
BTL mode
VDD=5V
0.005
0.005
RL=4ohm
Av=6dB
0.002
0.001
0.002
0.001
10m
20m
50m
100m
200m
Output Power [W]
500m
1
2
3
10m
20m
50m
100m
200m
500m
1
2
3
Output Power [W]
Figure 1. THD+N vs. Output Power
Figure 2. THD+N vs. Output Power
10
5
10
5
BTL mode
VDD=3.3V
RL=8ohm
Av=6dB
2
1
2
1
20kHz
0.5
0.5
20kHz
0.2
0.1
0.2
0.1
1kHz
1kHz
20Hz
0.05
0.05
0.02
0.01
0.02
0.01
20Hz
BTL mode
VDD=3.3V
RL=4ohm
Av=6dB
0.005
0.005
0.002
0.001
0.002
0.001
10m
20m
50m
100m
200m
500m
1
2
10m
20m
50m
100m
200m
500m
1
Output Power [W]
Output Power [W]
Figure 3. THD+N vs. Output Power
Figure 4. THD+N vs. Output Power
10
5
10
5
BTL mode
VDD=2.7V
RL=8ohm
Av=6dB
2
1
2
1
20kHz
1kHz
0.5
0.5
20kHz
0.2
0.1
0.2
0.1
1kHz
0.05
0.05
0.02
0.01
0.02
0.01
20Hz
20Hz
BTL mode
VDD=2.7V
RL=4ohm
Av=6dB
0.005
0.005
0.002
0.001
0.002
0.001
10m
20m
50m
100m
200m
500m
1
10m
20m
50m
100m
200m
500m
1
Output Power [W]
Figure 5. THD+N vs. Output Power
Figure 6. THD+N Ovustp.ut OPowuert[pW]ut Power
6
FAN7031
Performance Characteristics(Continued)
10
10
5
BTL mode
Single-ended mode
20kHz
21.6dB
5
VDD=5V
VDD=5V
RL=4ohm
15.6dB
RL=32ohm
10.3dB
2
2
1
Av=4.3dB
6dB
1
0.5
0.5
0.2
0.2
0.1
20kHz
0.1
1kHz
0.05
0.05
1kHz
6dB
10.3dB
20Hz
0.02
0.01
0.02
0.01
15.6dB
21.6dB
100u
200u
500u
1m
2m
5m
10m
20m
50m
100m 200m
10m
20m
50m
100m
200m
500m
1
2
3
Output Power [W]
Output Power [W]
Figure 7. THD+N vs. Output Power
Figure 8. THD+N vs. Gain
10
5
10
5
20kHz
21.6dB
20kHz
21.6dB
15.6dB
15.6dB
10.3dB
10.3dB
2
1
2
1
6dB
6dB
0.5
0.5
0.2
0.1
0.2
0.1
0.05
0.05
1kHz
1kHz
6dB
6dB
BTL mode
BTL mode
VDD=2.7V
RL=4ohm
10.3dB
10.3dB
VDD=3.3V
RL=4ohm
0.02
0.01
0.02
0.01
15.6dB
15.6dB
21.6dB
21.6dB
10m
20m
50m
100m
200m
500m
1
2
10m
20m
50m
100m
200m
500m
1
Output Power [W]
Figure 9. THD+N vs. Gain
Figure 10. OTuHtpuDt P+owNer [Wv]s. Gain
10
5
10
5
VDD=3.3V
VDD=5V
Output power = 500mW
RL=4ohm
Output power =1W
RL=4ohm
2
1
2
1
0.5
0.5
0.2
0.1
0.2
0.1
0.05
0.05
0.02
0.01
0.02
0.01
0.005
0.005
0.002
0.001
0.002
0.001
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Figure 11. THD+NFvresqu.enFcyr[Hezq] uency
Figure 12. THD+NFvresqu.enFcyr[Hez]quency
7
FAN7031
Performance Characteristics(Continued)
10
10
5
5
VDD=2.7V
Single-ended mode
VDD=5V
Output power = 250mW
2
RL=4ohm
Output power = 50mW
RL=32ohm
2
1
1
0.5
0.2
0.1
0.5
0.2
0.1
0.05
0.02
0.01
0.05
0.005
0.02
0.01
0.002
0.001
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Frequency [Hz]
Frequency [Hz]
Figure 13. THD+N vs. Frequency
Figure 14. THD+N vs. Frequency
+0
+0
-10
VDD=5V
-10
VDD=5V
Output power = 1W
RL=4ohm
Output power = 1W
RL=8ohm
-20
-30
-20
-30
-40
-40
-50
-50
-60
-60
-70
-70
-80
-80
Left-to-Right
Right-to-Left
-90
-90
Right-to-Left
-100
-110
-100
-110
Left-to-Right
-120
-120
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Frequency [Hz]
Figure 15. CrosstalFkreqvuesnc.yF[Hrz]equency
Figure 16. Crosstalk vs. Frequency
+0
+0
-10
Single-ended mode
-10
VDD=5V+/-5%
VDD=5V
RL=4ohm
-20
-30
-20
-30
Output power = 50mW
RL=32ohm
-40
-40
-50
-50
-60
-60
-70
-70
-80
-80
Right-to-Left
-90
-90
-100
-110
-100
-110
Left-to-Right
-120
-120
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Figure 17. CrosstalFkreqvuesnc.yF[Hrz]equency
Figure 18. PSRR Fvresqu.enFcyr[eHzq] uency
8
FAN7031
Performance Characteristics(Continued)
+0
+0
-10
-10
VDD=2.7V+/-5%
RL=4ohm
VDD=3.3V+/-5%
RL=4ohm
-20
-20
-30
-30
-40
-40
-50
-50
-60
-60
-70
-70
-80
-80
-90
-90
-100
-110
-100
-110
-120
-120
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Frequency [Hz]
Frequency [Hz]
Figure 19. PSRR vs. Frequency
Figure 20. PSRR vs. Frequency
+0
+0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-10
-20
-30
-40
-50
-60
-70
-80
-90
Single-ended mode
Single-ended mode
VDD=5V+/-5%
RL=32ohm
VDD=3.3V+/-5%
RL=32ohm
Cbyp=0.47uF
Cbyp=0.47uF
-100
-100
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Frequency [Hz]
Frequency [Hz]
Figure 21. PSRR vs. Frequency
Figure 22. PSRR vs. Frequency
+0
+0
-10
-10
0.1µF
0.47µF
-20
-30
-40
-50
-60
-70
-80
-90
-20
-30
-40
-50
-60
-70
-80
-90
1µF
4.7µF
10µF
Single-ended mode
VDD=2.7V+/-5%
RL=32ohm
Single-ended mode
VDD=5V+/-5%
RL=32ohm
Cbyp=0.47uF
-100
-100
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Frequency [Hz]
Frequency [Hz]
Figure 23. PSRR vs. Frequency
Figure 24. PSRR vs. Bybass Capacitor
9
FAN7031
Performance Characteristics(Continued)
+20
+20
+15
G0=VDD, G1=VDD
G0=VDD, G1=VDD
G0=VDD, G1=GND
+15
G0=VDD, G1=GND
+10
+10
+5
G0=GND, G1=VDD
G0=GND, G1=VDD
G0=GND, G1=GND
+5
G0=GND, G1=GND
VDD=5V
VDD=3.3V
No load
No load
Cin=0.47uF
Cin=0.47uF
+0
+0
20
50
100
200
500
1k
2k
5k
10k
20k
20
50
100
200
500
1k
2k
5k
10k
20k
Frequency [Hz]
Frequency [Hz]
Figure 25. BTL Mode Gain vs. Frequency
Figure 26. BTL Mode Gain vs. Frequency
6.0m
5.0m
4.0m
3.0m
2.0m
1.0m
0.0
+20
G0=VDD, G1=VDD
+15
+10
+5
G0=VDD, G1=GND
G0=GND, G1=VDD
G0=GND, G1=GND
VDD=2.7V
No load
Cin=0.47uF
+0
20
50
100
200
500
1k
2k
5k
10k
20k
0
1
2
3
4
5
Frequency [Hz]
Figure 27. BTL Mode Gain vs. Frequency
Figure 28. IDDSvupsply.VSoltaugep[Vp] ly Voltage
25.0n
20.0n
15.0n
10.0n
5.0n
8.0m
6.0m
4.0m
2.0m
0.0
VDD=5V
VDD=3.3V
VDD=2.7V
0.0
-1
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
Figure 29. Shutdown SCupuplyrVroeltanget[Vv] s. Supply Voltage
Figure 30. IDD vs. Shutdown Pin Voltage
Shutdown Pin Voltage [V]
10
FAN7031
Performance Characteristics(Continued)
5.5m
4.5m
4.0m
3.5m
3.0m
2.5m
5.0m
BTL mode
BTL mode
4.5m
Single-Ended
4.0m
Single-Ended
mode
mode
3.5m
VDD=3.3V
VDD=5V
3.0m
0
1
2
3
4
5
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
SE/BTL Pin Voltage [V]
SE/BTL Pin Voltage [V]
Figure 31. IDD vs. SE/BTL Pin Voltage
Figure 32. IDD vs. SE/BTL Pin Voltage
4.5m
4.0m
3.5m
3.0m
2.5m
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
VDD=5V
BTL mode
Single-Ended
mode
VDD=3.3V
VDD=2.7V
THD less than 1%
RL=8ohm
VDD=2.7V
f=1kHz
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0.0
0.5
1.0
1.5
SE/BTL Pin Voltage [V]
Output Power [W]
Figure 33. IDD vs. SE/BTL Pin Voltage
Figure 34. Power Dissipation vs. Output Power
3.0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
BTL mode
f=1kHz
VDD=5V
2.5
2.0
1.5
1.0
0.5
0.0
RL=4ohm
10% THD+N
1% THD+N
VDD=3.3V
VDD=2.7V
THD less than 1%
RL=4ohm
f=1kHz
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Output Power [W]
Supply Voltage [V]
Figure 35. Power Dissipation vs. Output Power
Figure 36. Output Power vs. Supply Voltage
11
FAN7031
Performance Characteristics(Continued)
2.0
2.5
2.0
1.5
1.0
0.5
0.0
BTL mode
VDD=5V
f=1kHz
BTL mode
f=1kHz
RL=8ohm
1.5
10% THD+N
1.0
10% THD+N
1% THD+N
1% THD+N
0.5
0.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0
8
16
24
32
40
48
56
64
Supply Voltage [V]
RL-Load Resistance [Ω]
Figure 37. Output Power vs. Supply Voltage
Figure 38. Output Power vs. Load Resistance
1.2
0.7
BTL mode
BTL mode
VDD=3.3V
f=1kHz
VDD=2.7V
f=1kHz
0.6
0.5
0.4
0.3
0.2
0.1
0.0
1.0
0.8
0.6
0.4
0.2
0.0
10% THD+N
10% THD+N
1% THD+N
1% THD+N
0
8
16
24
32
40
48
56
64
0
8
16
24
32
40
48
56
64
RL-Load Resistance [Ω]
RL-Load Resistance [Ω]
Figure 39. Output Power vs. Load Resistance
Figure 40. Output Power vs. Load Resistance
800.0m
700.0m
600.0m
500.0m
400.0m
300.0m
200.0m
100.0m
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Single-Ended mode
VDD=3.3V
Single-Ended mode
VDD=5V
f=1kHz
f=1kHz
10% THD+N
1% THD+N
10% THD+N
1% THD+N
0.0
0
8
16
24
32
40
48
56
64
0
8
16
24
32
40
48
56
64
RL-Load Resistance [Ω]
Figure 41. Output Power vs. Load Resistance
Figure 42. Output PRoLw-LoaedrRevsissta.ncLe [oΩ]ad Resistance
12
FAN7031
Performance Characteristics(Continued)
0.20
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Single-Ended mode
VDD=2.7V
f=1kHz
M ulti La yer
0.15
0.10
10% THD+N
Single La ye r
0.05
1% THD+N
0.00
0
25
50
75
100
125
150
0
8
16
24
32
40
48
56
64
Am bient Tem perature [°C]
RL-Load Resistance [Ω]
Figure 43. Output Power vs. Load Resistance
Figure 44. Power Derating Curve
13
FAN7031
Typical Application Circuits
Single-Ended Inputs
VDD
10µF
104
VDD
6,15,16
0.47µF
Right channel
RIN- 17
RIN+ 7
Single ended Input
18 ROUT+
0.47µF
Right
Output
(BTL)
330µF
14
ROUT-
VDD
1kΩ
VDD
100kΩ
SD
BYPASS
10
19
BIAS
&
G0
G1
2
3
Stereo
Output
1µF
CONTROL
100kΩ
SE/BTL
10kΩ
10kΩ
10kΩ
0.47µF
12
4
LIN+ 9
LOUT+
1kΩ
Left channel Single
ended Input
5
LIN-
330µF
0.47µF
Left
Output
(BTL)
8
LOUT-
1,11,20
GND
14
FAN7031
Typical Application Circuits(Continued)
Differential Inputs
VDD
10µF
104
VDD
6,15,16
0.47µF
Right channel
RIN- 17
RIN+ 7
Differential Input
18 ROUT+
0.47µF
Right
Output
(BTL)
330µF
14
ROUT-
VDD
1kΩ
VDD
100kΩ
BYPASS
SD
10
19
BIAS
&
G0
G1
2
3
Stereo
Output
1µF
CONTROL
10kΩ
10kΩ
10kΩ
0.47µF
100kΩ
SE/BTL
12
4
LIN+ 9
LOUT+
1kΩ
Left channel
5
LIN-
Differential Input
330µF
0.47µF
Left
Output
(BTL)
8
LOUT-
1,11,20
GND
15
FAN7031
Functional Description
The FAN7031 is a stereo 2W amplifier capable of delivering 1.85W continuous RMS power into a 4-ohm load. This
device has less than 0.75% THD+N across the entire frequency range at an output power of 1W. A thermally
enhanced TSSOP package is used to allow for maximum dissipation of package heat.
Gain selection is achieved by driving G0 and G1 inputs according to the table below.
G0
0
0
1
1
G1
0
1
0
1
SE/BTL
A
6dB
10.3dB
15.6dB
21.6dB
4.3dB
Zin
V
0
0
0
0
1
90kΩ
55kΩ
30kΩ
15kΩ
55kΩ
X
X
Gain select pins are activated only when SE/BTL pin is set to low level. If SE/BTL pin is high, the amplifier configu-
ration is changed as SE(single-ended) mode and the gain of SE amplifier is fixed to 4.3dB (about 1.64).
Gain is varied by changing the taps on input resistors, and such change in gain will cause variation in the input
impedance. Input impedance (Zin) is described in the above table. The impedance variation determines amplifier
lowest bandwidth. Thus, input DC decoupling capacitors must be carefully selected.
Applications Information
PCB Layout and Supply Regulation
Metal trace resistance between the BTL output and the parasitic resistance of the power supply line both heavily
affect the output power. In order to obtain the maximum power depicted in the performance characteristics figures,
outputs, power and ground lines need wide metal trace. The parasitic resistance of the power line increases ripple
noise and degrades the THD and PSRR performance. To reduce such unwanted effect, large capacitor must be
connected between V
DD
use a low ESR capacitor.
pin and GND pin as close as possible. To improve power supply regulation performance,
Power Supply Bypassing
Selection of proper power supply bypassing capacitor is critical to obtaining lower noise as well as higher power
supply rejection. Larger capacitors may help to increase immunity to the supply noise. However, considering eco-
nomical design, attaching 10µF electrolytic capacitor or tantalum capacitor with 0.1µF ceramic capacitor as close
as possible to the VDD pins are enough to get a good supply noise rejection.
Selection of Input Capacitor
Input capacitor blocks DC signal also low frequency input signal. Thus, this capacitor acts as a high pass filter. The
-3dB frequency of this filter is determined by input capacitor and input impedance of the amplifier. The frequency is
1
f
= ----------------------------
–3dB
2π ⋅ Zin ⋅ C
As shown previously, the input impedance is changed by selecting gain. Considering smallest Zin (=15kW), the
capacitance which meets f
frequency of 20Hz is 0.53uF. Thus, selecting the capacitance higher than 0.53uF,
-3dB
the lowest frequency of audio signal can be amplified without gain loss.
16
FAN7031
BLT Mode of Operation vs. Single Ended Mode of Operation
The FAN7031 offers both BTL (Bridge-Tied Load) and SE (Single Ended) operation. When SE/BTL pin is low, BTL
operation is selected. In BTL operation, maximum output power is increased 4 times comparing with SE operation
at the same load, output swing and supply condition because output swing is doubled. Thus, BTL mode is useful to
drive a speaker load. On the other hand, when SE/BTL pin is high, one amplifier configured BTL driver is turned off
and only single amplifier is activated. In this mode, maximum output power is reduced and the quiescent power
consumption is saved about half. Thus, SE mode is adequate for head-phone load. The output power of BTL and
SE are expressed as follows respectively:
2
Vp
---------------
P
=
,
BTL
2 ⋅ RL
2
Vp
---------------
P
=
.
SE
8 ⋅ RL
To use the amplifier in SE mode, the output DC voltage must be blocked not to increase power consumption. Thus,
the load is tied to output via output DC blocking capacitor. The capacitor size can be chosen using above f-
3dB
equation. For example, assuming the load impedance is 32W, 249uF capacitor guarantees 20Hz signal transmis-
sion to the load without gain reduction.
Shutdown Mode
The device moves to a shutdown mode when the shutdown pin is at 0V. For normal operation the shutdown pin
should be at V . This pin should never be left unconnected.
DD
17
FAN7031
Mechanical Dimensions
Package
Dimensions in millimeters
20TSSOP-EP
18
FAN7031
Ordering Information
Device
Package
Operating Temperature
FAN7031MTF
20TSSOP-EP
-40°C ~ +85°C
19
FAN7031
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and (c) whose failure to
perform when properly used in accordance with
instructions for use provided in the labeling, can be
reasonably expected to result in a significant injury of the
user.
2. A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
8/11/03 0.0m 001
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2003 Fairchild Semiconductor Corporation
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