www.fairchildsemi.com
FAN7021
CMOS Power Amplifier
Features
• Continuous average power is 1.0W (8Ω)
• Low THD: under 0.2% (5V)
• Do not need output coupling capacitor or bootstrap
capacitor
• Low shutdown current: 0.01µA
• Shutdown: High active
• Built in reduction circuit for popping noise
• Built in TSD circuit
Description
The FAN7021 is a bridge connected audio power amplifier
capable of delivering 1W of continuous average power to an
8Ω load with less than 0.2%(THD) from a 5V power supply.
The FAN7021 require few external components and operate
on low supply voltage from 2.0V to 5.5V. Since the
FAN7021 does not require output coupling capacitor,
bootstrap capacitors, or snubber networks, it is ideally suited
for low power portable systems that require minimum
volume and weight. The FAN7021 feqtures an externally
controlled, low power consumption shutdown mode (0.01
uA,typ). Additional FAN7021 features include thermal
shutdown protection, unity gain stability, and external gain
set.
8-SOP-225
Typical Applications
• Cellular phone
• Portable computer
• Audio systems
1
Internal Block Diagram
IN-
4
5 V
O1
IN+ 3
20K
20K
BP
2
100K
V
DD
6
8 V
O2
SD
1
Bias
100K
7
GND
Rev. 1.0.0
©2001 Fairchild Semiconductor Corporation
FAN7021
Pin Assignments
V
O2
8
GND
7
V
DD
6
V
O1
5
FAN7021
1
SD
2
BP
3
IN+
4
IN-
Pin Definitions
Pin Number
1
2
3
4
5
6
7
8
Pin Name
SD
BP
IN+
IN−
V
O1
V
DD
GND
V
O2
Pin Function Description
Shutdown
Bypass
Input +
Input
−
Power AMP output 1
Supply Voltage
Ground
Power AMP output 2
Absolute Maximum Ratings (Ta = 25°C)
°
Parameter
Maximum Supply Voltage
Power Dissipation
Operating Temperature
Storage Temperature
Symbol
V
DD
P
D
T
OPR
T
STG
Value
6.0
-
−40
~ +85
−65
~ +150
Unit
V
W
°C
°C
Remark
Maximum supply voltage
-
Operating temperature
Storage temperature
Recommended Operating Conditions (Ta = 25°C)
°
Parameter
Operating Supply Voltage
Symbol
V
DD
Min.
2.0
Typ.
-
Max.
5.5
Unit
V
2
FAN7021
Electrical Characteristics
(R
L
= 8Ω
, Ta = 25°C,
Unless otherwise specified)
Parameter
Quiescent power supply current
Shutdown current
Output offset voltage
Output power
Total harmonic distortion+Noise
Power supply rejection ratio
Quiescent power supply current
Shutdown current
Output offset voltage
Output power
Total harmonic distortion+Noise
Power supply rejection ratio
Quiescent power supply current
Shutdown current
Output offset voltage
Output power
Total harmonic distortion+Noise
Power supply rejection ratio
Symbol
I
DD
I
SD
V
OS
P
O
THD+N
PSRR
I
DD
I
SD
V
OS
P
O
THD+N
PSRR
I
DD
I
SD
V
OS
P
O
THD+N
PSRR
Conditions
V
IN
=0V,I
O
=0A
V
SD
=V
DD
V
IN
=0V
THD=0.2% (Max.);f=1KHz
P
O
=0.25Wrms,A
VD
=2,filter=80KHz
f=1KHz
f=20KHz
V
DD
=4.9V to 5.1V
V
IN
=0V,I
O
=0A
V
SD
=V
DD
V
IN
=0V
THD=1% (Max.);f=1KHz
P
O
=0.25Wrms,A
VD
=2,filter=80KHz
f=1KHz
f=20KHz
V
DD
=3.2V to 3.4V
V
IN
=0V,I
O
=0A
V
SD
=V
DD
V
IN
=0V
THD=0.3% (Max.);f=1KHz
P
O
=0.25Wrms,A
VD
=2,filter=80KHz
f=1KHz
f=20KHz
V
DD
=2.5V to 2.7V
-
-
-
0.25
0.5
65
-
-
-
%
%
dB
V
DD
= 2.6V, UNLESS OTHERWISE SPECIFIED
-
-
-
-
2.5
0.01
5
0.25
-
-
-
-
mA
µA
mV
W
-
-
-
0.15
0.45
65
-
-
-
%
%
dB
V
DD
= 3.3V, UNLESS OTHERWISE SPECIFIED
-
-
-
0.45
3.0
0.01
5
0.5
-
-
-
-
mA
µA
mV
W
-
-
-
0.1
0.4
65
-
-
-
%
%
dB
Min.
-
-
-
-
Typ.
4.0
0.01
5
1
Max.
7.0
2.0
50
-
Unit
mA
µA
mV
W
V
DD
= 5.0V, UNLESS OTHERWISE SPECIFIED
3
FAN7021
Typical Application Circuits
R
F
20K
C
I
0.39u
4
R
I
20K
3
+
IN-
5
V
O1
IN+
20K
C
B
1u
+
20K
V
DD
2
BP
Speaker
8
Ω
V
DD
100K
V
O2
8
R
PU
10K
+
6
C
S
1u
1
Bias
SD
7
100K
GND
4
FAN7021
Performance Characteristics
Figure 1. THD+N versus output power
Figure 2. THD+N versus output power
Figure 3. THD+N versus output power
Figure 4. THD+N versus Frequency
Figure 5. THD+N versus Frequency
Figure 6. THD+N versus Frequency
5
