PAM8302AASCR [PAM]
2.5W Filterless Class-D Mono Audio Amplifier; 2.5W无滤波D类单声道音频放大器型号: | PAM8302AASCR |
厂家: | POWER ANALOG MICOELECTRONICS |
描述: | 2.5W Filterless Class-D Mono Audio Amplifier |
文件: | 总14页 (文件大小:223K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Key Features
General Description
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2.5W Output at 10% THD with a 4Ω Load
and 5V Power Supply
Filterless, Low Quiescent Current and Low
EMI
High Efficiency up to 88%
Superior Low Noise
Short Circuit Protection
Thermal Shutdown
The PAM8302A is a 2.5W class-D mono audio
amplifier. Its low THD+N feature offers high-
quality sound reproduction. The new filterless
architecture allows the device to drive speaker
directly instead of using low-pass output filters,
therefore save system cost and PCB area.
With the same number of external components,
the efficiency of the PAM8302A is much better
than that of class-AB cousins. It can optimize
battery life thus is ideal for portable applications.
Few External Components to Save Space
and Cost
n MSOP-8, SOP-8 and DFN3x3 Packages
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Available
Pb-Free Package
The PAM8302A is available in MSOP-8, SOP-8
and DFN3x3 packages.
Applications
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PMP/MP4
GPS
Portable Speakers
Walkie Talkie
Handsfree phones/Speaker Phones
Cellular Phones
Typical Application
1μF
6
VDD
Ci
Ci
Ri
Ri
4
IN-
IN-
8
5
VO-
VO+
Differential
Input
PAM8302A
3
1
IN+
/SD
IN+
ON
OFF
GND
7
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
1
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Block Diagram
VDD
IN+
IN-
VO+
VO-
DRIVER
MODULATOR
THERMAL
PROTECTION
INTERNAL
OSCILLATOR
SHORT
PROTECTION
SHUTDOWN
SD
OSC
GND
Pin Configuration & Marking Information
Top View
DFN3x3
Top View
MSOP-8/SOP-8
1
8
7
6
5
VO-
SD
NC
IN+
IN-
SD
NC
IN+
IN-
1
2
3
4
8
7
6
5
VO-
X: Internal Code
Y: Year
W: Week
2
3
GND
VDD
VO+
GND
VDD
VO+
P8302A
XXXXYW
4
Pin Number
Pin name
SD
Description
1
2
3
4
5
6
7
8
Shutdown terminal ,active low
No connection
NC
IN+
Positive differential input
Negative differential input
Positive BTL output
Analog power supply
Ground
IN-
VO+
VDD
GND
VO-
Negative BTL output
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
2
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Absolute Maximum Ratings
These are stress ratings only and functional operation is not implied. Exposure to absolute
maximum ratings for prolonged time periods may affect device reliability. All voltages are with
respect to ground.
Supply Voltage at no Input Signal...................6.6V
Input Voltage.............................-0.3V to VDD+0.3V
Maximum Junction Temperature..................150°C
Storage Temperature.....................-65°C to 150°C
Soldering Temperature.......................300°C,5sec
Recommended Operating Conditions
Supply voltage Range........................2.5V to 5.5V
Max. Supply Voltage (for Max. duration of
30 minutes)................................................6.0V
Ambient Operation Temperature
Range......................................... -40°Cto 85°C
Junction Temperature Range.........-40°C to 125°C
Thermal Information
Parameter
Symbol
Package
SOP-8
Maximum
115
Unit
°C/W
°C/W
°C/W
Thermal Resistance
(Junction to ambient)
θJA
MSOP-8
DFN 3x3-8
180
47.9
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
3
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Electrical Characteristic
VDD=5V, Gain = 24dB, RL=4Ω,TA=25°C,unless otherwise noted.
PARAMETER
Supply Voltage Range
Quiescent Current
SYMBOL
VDD
CONDITIONS
MIN
TYP
MAX UNITS
2.5
5.5
8
V
IQ
No Load
4
mA
μA
Shutdown Current
ISHDN
VSHDN=0V
1
f=1kHz, RL=4Ω
THD+N=10%
VDD=5V
DD=3.6V
VDD=5V
DD=3.6V
VDD=5V
DD=3.6V
2.50
1.25
2.00
0.95
1.50
0.80
1.30
0.65
85
V
f=1kHz, RL=4Ω
THD+N=1%
V
Output Power
PO
W
f=1kHz, RL=8Ω
THD+N=10%
F=1kHz, RL=8Ω
THD+N=1%
V
VDD=5V
VDD=3.6V
Peak Efficiency
η
f=1kHz
88
%
%
RL = 8Ω,PO=0.1W, f=1kHz
RL = 8Ω,PO=0.5W, f=1kHz
RL = 4Ω,PO=0.1W, f=1kHz
RL = 4Ω,PO=0.5W, f=1kHz
0.30
0.45
0.35
0.40
24
Total Harmonic Distortion Plus
Noise
THD+N
Gain
Gv
PSRR
Dyn
dB
dB
dB
dB
Power Supply Ripple Rejection
Dynamic Range
Signal to Noise Ratio
No input, f=1kHz, Vpp=200mV
f=20 to 20kHz
45
50
90
SNR
f =20 to 20kHz
80
No A-weighting
180
120
250
0.45
0.20
Noise
Vn
fOSC
μV
kHz
Ω
A-weighting
Oscillator Frequency
Drain-Source On-State
Resistance
200
1.2
300
0.4
P MOSFET
IDS=100mA
N MOSFET
RDS(ON)
VSH
VSL
V
V
SHDN Input High
SHDN Input Low
Over Temperature Protection
Over Temperature Hysteresis
OTP
OTH
135
30
°C
°C
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
4
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Typical Performance Characteristics
TA=25OC, unless otherwise noted.
THD+N VS Output Power
RL=4Ω, Gain=23dB, f=1kHz
THD+N VS Output Power
RL=8Ω, Gain=23dB, f=1kHz
50
50
V D D = 3 . 6 V
20
10
5
V D D = 3 . 6 V
V D D = 4 . 2 V
20
10
5
V D D = 4 . 2 V
%
%
2
1
2
1
0. 5
0.5
V D D = 5 V
0. 2
0. 1
0.2
0.1
V D D = 5 V
20m
50m
100m
200m
500m
1
2
3
20m
50m
10m0
20m0
50m0
1
2
3
W
W
THD+N VS Frequency
THD+N VS Frequency
RL=8Ω, Cin=0.1μF, Gain=23dB, VDD=5V
RL=8Ω, Cin=0.1μF, Gain=23dB, VDD=3.6V
10
5
10
5
Po=200mW
2
2
1
1
0. 5
Po=500mW
0. 5
%
%
Po=500mW
0. 2
0. 1
0. 2
0. 1
0. 05
Po=200mW
0.05
0. 02
0. 01
0.02
20
50
100
200
500
Hz
1k
2k
5k
10k 20k
20
50
100
200
500
Hz
1k
2k
5k
10k 20k
THD+N VS Frequency
THD+N VS Frequency
RL=4Ω, Cin=0.1μF, Gain=23dB, VDD=3.6V
RL=4Ω, Cin=0.1μF, Gain=23dB, VDD=5V
10
5
10
5
Po=200mW
2
2
1
1
Po=500mW
0.5
0.5
%
%
Po=500mW
0.2
0.1
0.2
0.1
Po=200mW
0. 0 5
0.0 5
0. 0 2
0. 0 1
0.0 2
20
20
50
100
200
500
Hz
1k
2k
5k
10k 20k
50
100
200
500
Hz
1k
2k
5k
10k 20k
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
5
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Typical Performance Characteristics
TA=25OC, unless otherwise noted.
Quiescent Current VS Temperature
Frequency VS Temperature
No input, No Load, VDD=5.0V
No input, No Load, VDD=5.0V
8
350
300
250
200
150
100
50
7
6
5
4
3
2
1
0
0
0
50
100
Temperature
150
0
50
100
150
Temperature
Supply Current VS Output Power
VDD=5.0V
Supply Current VS Output Power
Rl=8Ω+33μH
0.4
0.35
0.3
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0.25
0.2
0.15
0.1
0.05
0
Load=8ohm+33uH
L=4ohm+33uH
VDD=3.6V
VDD=5V
0
500
1000
1500
2000
0
500
1000
1500
2000
2500
3000
Output Power(mW)
Output Power(mW)
Output Power VS. Supply Voltage
Rl=8Ω
Output Power VS. Supply Voltage
Rl=4Ω
3.5
2.5
3
2
2.5
1.5
2
1.5
1
1
0.5
THD=1%
0.5
THD+N=1%
THD=10%
THD+N=10%
0
0
2.5
2.8
3
3.2 3.4 3.6 3.8
4
4.2 4.4 4.6 4.8
5
5.2 5.4
3
3.5
4
4.5
5
5.5
Supply Voltage(V)
Supply Voltage(V)
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
6
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Typical Performance Characteristics
TA=25OC, unless otherwise noted.
Efficiency VS Output Power
Efficiency VS Output Power
Rl=8Ω+33μΗ
VDD=5.0V
95%
95%
90%
85%
80%
75%
70%
65%
60%
90%
85%
80%
75%
70%
65%
60%
Load=8ohm+33uH
Load=4ohm+33uH
Vin=5V
Vin=3.6V
0
500
1000
1500
2000
0
500
1000
1500
2000
2500
3000
Output Pow er(m W)
Output Pow er(m W)
Quiescent Current VS. Supply Voltage
No load
Frequency VS. Supply Voltage
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
2.5
350
300
250
200
150
100
50
0
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5
5.5
Supply Voltage(V)
Supply Voltage(V)
Power Dissipation VS. Output Power
Rl=8Ω
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0.00
VDD=5V
VDD=3.6V
0
500
1000
1500
2000
Output Pow er(W)
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
7
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Test Setup for Performance Testing
PAM8302A Demo Board
Load
+OUT
AP
Input
Low Pass
AP System One
Analyzer
AP System One
Generator
Filter
-OUT
AUX-0025
GND
VDD
Power Supply
Notes
1. The AP AUX-0025 low pass filter is necessary for every class-D amplifier measurement
with AP analyzer.
2. Two 22µH inductors are used in series with load resistor to emulate the small speaker for
efficiency measurement.
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
8
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Application Information
Maximum Gain
capacitor is the best choice. When a polarized
capacitor is used, the positive side of the
As shown in block diagram (page 2), the
PAM8302A has two internal amplifier stages. The
first stage's gain is externally configurable, while
the second stage's is internally fixed. The closed-
loop gain of the first stage is set by selecting the
ratio of Rf to Ri while the second stage's gain is
fixed at 2x.The output of amplifier 1 serves as the
input to amplifier 2, thus the two amplifiers
produce signals identical in magnitude, but
different in phase by 180°. Consequently, the
differential gain for the IC is
capacitor should face the amplifier input in most
applications as the DC level is held at VDD/2,
which is likely higher than the source DC level.
Please note that it is important to confirm the
capacitor polarity in the application.
Power Supply Decoupling (Cs)
The PAM8302A is a high-performance CMOS
audio amplifier that requires adequate power
supply decoupling to ensure the output THD and
PSRR as low as possible. Power supply
decoupling affects low frequency response.
Optimum decoupling is achieved by using two
capacitors of different types that target different
types of noise on the power supply leads. For
higher frequency transients, spikes, or digital
hash on the line, a good low equivalent-series-
resistance (ESR) ceramic capacitor, typically
1.0μF is good, placing it as close as possible to
the device VDD terminal. For filtering lower-
frequency noise signals, a capacitor of 10μF or
AVD=20*log [2*(Rf/Ri)]
The PAM8302A sets maximum Rf=80kΩ, minimum
Ri=10kΩ, so the maximum closed-gain is 24dB.
Input Capacitors (Ci)
In typical application, an input capacitor, Ci, is
required to allow the amplifier to bias input
signals to a proper DC level for optimum
operation. In this case, Ci and the minimum input
impedance Ri (10k internal) form a high pass filter
with a corner frequency determined by the
following equation:
larger, closely located to near the audio power
amplifier is recommended.
Shutdown Operation
1
fC =
2pRiCi
(
)
In order to reduce shutdown power consumption,
the PAM8302A contains shutdown circuitry for
turn off the amplifier. This shutdown feature turns
the amplifier off when a logic low is applied on the
SD pin. By switching the shutdown pin over to
GND, the PAM8302A supply current draw will be
minimized in idle mode.
It is important to choose the value of Ci as it
directly affects low frequency performance of the
circuit, for example, when an application requires
a flat bass response as low as 100Hz. Equation is
reconfigured as follows:
1
For the best power on/off pop performance,
the amplifier should be set in the shutdown
mode prior to power on/off operation.
Ci =
2pR
ifc
(
)
As the input resistance is variable, for the Ci
value of 0.16ꢀF, one should actually choose the
Ci within the range of 0.1ꢀF to 0.22ꢀF. A further
consideration for this capacitor is the leakage
path from the input source through the input
network (Ri, RF,Ci) to the load. This leakage
current creates a DC offset voltage at the input to
the amplifier that reduces useful headroom,
especially in high gain application. For this
reason, a low leakage tantalum or ceramic
Under Voltage Lock-out (UVLO)
The PAM8302A incorporates circuitry to detect
low on or off voltage. When the supply voltage
drops to 2.1V or below, the PAM8302A goes into a
state of shutdown, and the device comes out of its
shutdown state and starts to normal operation by
reset the power supply or SD pin.
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
9
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
How to Reduce EMI (Electro Magnetic Interference)
A simple solution is to put an additional capacitor 1000μF at power supply terminal for power line coupling
if the traces from amplifier to speakers are short (<20CM).
Most applications require a ferrite bead filter as shown at Figure 1. The ferrite filter depresses EMI of
around 1MHz and higher. When selecting a ferrite bead, choose one with high impedance at high
frequencies and low impedance at low frequencies.
Ferrite Bead
OUT+
220pF
Ferrite Bead
OUT-
220pF
Figure 1: Ferrite Bead Filter to reduce EMI
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
10
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Ordering Information
PAM8302A X X X X
Shipping Package
Number of pins
Package Type
Pin Configuration
Pin Configuration
Package Type
Number of pins
A:
S: MSOP
D : SOP
C : 8
1: SD
2: NC
Y: D FN 3X3
3: IN+
4: IN-
5: VO+
6: VDD
7: GND
8: VO-
Part Number
PAM8302AASCR
PAM8302AADCR
PAM8302AAYCR
Package Type
MSOP-8
MOQ/Shipping Package
2,500 Units/Tape & Reel
2,500 Units/Tape & Reel
3,000 Units/Tape & Reel
SOP-8
DFN3x3-8
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
11
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Outline Dimensions
MSOP-8
Millimeter
REF
Min
--
Max
1.10
0.15
0.94
0.38
0.23
3.10
3.10
5.05
A
A1
A2
b
0.05
0.78
0.22
0.08
2.90
2.90
4.75
c
D
E
E1
e
0.65BSC
L
0.40
0.70
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
12
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Outline Dimensions
DFN 3x3
DFN
Note: All dimensions are in Millimeters.
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
13
PAM8302A
2.5W Filterless Class-D Mono Audio Amplifier
Outline Dimensions
-
REF
DIMENSIONS
Millimeters
B
Min
5.80
4.80
3.80
0º
Max
6.20
5.00
4.00
8º
A
B
C
D
E
0.40
0.19
0.10
0.35
1.35
0.90
0.25
0.25
0.49
1.75
F
M
H
L
J
0.375 REF
45º
K
G
G
1.27 TYP
J
K
D
H
E
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
14
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