PAM8301 [PAM]
Filterless Class-D Mono Audio Amplifier; 无滤波器D类单声道音频放大器
| 型号： | PAM8301 |
| 厂家： | 
POWER ANALOG MICOELECTRONICS |
| 描述： | Filterless Class-D Mono Audio Amplifier |
| 文件： | 总11页 (文件大小：219K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
PAM8301
Filterless Class-D Mono Audio Amplifier
Key Features
General Description
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1.5W Output at 10% THD with a 8Ω 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 PAM8301 is a 1.5W 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 PAM8301 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 Tiny SOT23-6 Package
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Pb-Free Package
The PAM8301 is available in SOT23-6 package.
Applications
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PMP/MP4
GPS
Portable Speakers
Walkie Talkie
Handsfree phones/Speaker Phones
Cellular Phones
Typical Application
VDD
10μF
5
1μF
VDD
3
OUT+ 6
Audio
IN
0.1μF
PAM8301
4
OUT- 1
Shutdown
/SD
GND
2
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
1
PAM8301
Filterless Class-D Mono Audio Amplifier
Block Diagram
VDD
VDD/2
+
-
+OUT
IN
DRIVER
RI
-OUT
MODULATOR
RF
THERMAL
PROTECTION
INTERNAL
OSCILLATOR
CURRENT
PROTECTION
SHUTDOWN
SD
OSC
GND
Pin Configuration & Marking Information
TOP VIEW
SOT23-6
6
5
4
FP: Product Code of PAM8301
X: Internal Code
Y: Year
FPXYW
W: Week
1
2
3
Pin Number
Pin Name
OUT-
GND
Description
1
2
3
4
5
6
Negative Output
Ground
IN
Input
Shutdown, active low
Power Supply
Positive Output
SD
VDD
OUT+
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
2
PAM8301
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
Operation Temperature Range........ -40°C to 85°C
Junction Temperature Range.........-40°C to 125°C
Thermal Information
Parameter
Symbol
θJC
Package
SOT23-6
SOT23-6
Maximum
130
Unit
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient)
°C/W
θJA
250
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
3
PAM8301
Filterless Class-D Mono Audio Amplifier
Electrical Characteristic
VDD=5V, Gain = 24dB, RL=8Ω,TA=25°C，unless otherwise noted.
PARAMETER
Supply Voltage Range
Quiescent Current
SYMBOL CONDITIONS
MIN TYP MAX
UNITS
V
VDD
2.5
5.5
8
IQ
No Load
4
mA
Shutdown Current
ISHDN
VSH
VSL
VSHDN=0V
1
μA
1.2
SHDN Input High
SHDN Input Low
Drain-Source On-State
Resistance
V
Ω
0.4
P MOSFET
N MOSFET
THD+N=1%
THD+N=10%
0.45
0.20
1.2
1.5
0.2
0.3
50
RDS(ON)
IDS =100mA
f=1kHz
Output Power
PO
W
%
Total Harmonic Distortion Plus
RL = 8Ω，PO=200mW
RL = 8Ω，PO=0.5W
THD+N
Noise
Power Supply Ripple Rejection
Gain
PSRR
Gv
No input, f=1kHz, Vpp=200mV
45
dB
dB
24
No A-weighting
A-weighting
180
120
250
88
Noise
Vn
μV
Oscillator Frequency
fOSC
η
200
85
300
kHz
%
Peak Efficiency
f=1kHz
Signal to Noise Ratio
Over Temperature Protection
Over Temperature Hysteresis
SNR
OTP
OTH
f =20 to 20kHz
78
dB
°C
°C
135
30
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
4
PAM8301
Filterless Class-D Mono Audio Amplifier
Typical Performance Characteristic
TA=25°C,unless otherwise noted.
2. Frequency VS Temperature
1. Frequency VS Supply Voltage
258
350
300
250
200
150
100
50
256
254
252
250
248
246
244
242
240
238
0
2
3
4
5
6
0
20
40
60
80
100
120
140
Supply Voltage (V)
Temperature
3.Efficiency VS Output Power
4.Efficiency VS Output Power
90%
85%
80%
75%
70%
65%
60%
55%
50%
100%
95%
90%
85%
80%
75%
70%
65%
60%
RL=8Ω, VDD=3.6V/5V
RL=16Ω, VDD=3.6V/5V
VDD=5V
VDD=5V
VDD=3.6V
VDD=3.6V
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0
200
400
600
800
1000
1200
Output Pow er (mW)
Output Pow er(m W)
5. THD+N VS Output Power
6. THD+N VS Output Power
50
200
RL=16Ω,Gain=23dB, f=1kHz,
VDD=3.6V/5V/5.5V
RL=8Ω,Gain=23dB, f=1kHz,
VDD=3.6V/5V
100
50
20
10
5
3.6
V
5
V
20
10
5
3.6V
5V
2
1
%
%
2
1
0.5
0.5
0.2
0.1
0.2
0.1
20m
50m
100m
200 m
500m
1
2
3
20m
50m
100m
200m
500m
1
2
3
W
W
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
.
5
PAM8301
Filterless Class-D Mono Audio Amplifier
Typical Performance Characteristic
TA=25°C,unless otherwise noted.
7. THD+N VS Frequency
8. THD+N VS Frequency
10
5
10
RL=16Ω,Gain=23dB, Cin=0.1μF,
VDD=5V,Po=500mW
RL=8Ω,Gain=23dB, Cin=0.1μF,
VDD=5V,Po=500mW
5
2
1
2
1
%
%
0.5
0.5
0.2
0.1
0.2
0.1
0.05
0.03
0.06
20
20
50
100
200
500
1k
2k
5k
10k
20k
50
100
200
500
Hz
1k
2k
5k
10k
20k
Hz
9. THD+N VS Frequency
10. THD+N VS Frequency
10
5
10
RL=8Ω,Gain=23dB, Cin=0.1μF,
VDD=3.6V,Po=200mW
RL=16Ω,Gain=23dB, Cin=0.1μF,
VDD=3.6V,Po=200mW
5
2
1
2
1
%
%
0.5
0.5
0.2
0.2
0.08
20
0.08
20
50
100
200
500
1k
2k
5k
10k
20k
50
100
200
500
Hz
1k
2k
5k
10k
20k
Hz
11. Frequency Response
12. Noise Floor
+50
+45
+0
RL=16Ω,Cin=0.1μF,VDD=5V
Inputs floating, RL=8Ω,Cin=0.1μF,VDD=5V
-20
+40
+35
+30
+25
+20
-40
-60
d
B
r
d
B
V
-80
A
-100
-120
+15
+10
+5
-140
+0
20
20
50
100
200
500
1k
2k
5k
10k 20k
50
100
200
500
1k
2k
5k
10k
20k
Hz
Hz
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
6
PAM8301
Filterless Class-D Mono Audio Amplifier
Typical Performance Characteristic
TA=25°C unless otherwise noted.
14.EMI vs Frequency
13. PSRR
+
0
T T
T T
RL=8Ω,Gain=23dB,
VDD=5V,Input floating
RL=8Ω,Gain=23dB,
-
-
-
-
-
-
-
-
-
10
20
30
40
50
60
70
80
90
VDD=5V, Po=500mW
dB
-
100
20
50
100
200
500
Hz
1k
2k
5k
10k
.
Test Setup for Performance Testing
PAM8301 Demo Board
+OUT
Load
AP
Input
Low Pass
AP System One
Analyzer
AP System One
Generator
Filter
-OUT
GND
AUX-0025
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
7
PAM8301
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 PAM8301
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 PAM8301 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 PAM8301 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.
1
Shutdown Operation
fC =
2pRiCi
(
)
In order to reduce shutdown power consumption,
the PAM8301 contains shutdown circuitry for turn
off the amplifier. This shutdown feature turns the
amplifier off when a logic low is applied on the
SHDOWN pin. By switching the shutdown pin over
to GND, the PAM8301 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
Ci =
For the best power on/off pop performance,
the amplifier should be set in the shutdown
mode prior to power on/off operation.
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 PAM8301 incorporates circuitry to detect low
on or off voltage. When the supply voltage drops
to 2.1V or below, the PAM8301 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
8
PAM8301
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
9
PAM8301
Filterless Class-D Mono Audio Amplifier
Ordering Information
PAM8301 X X X
Number of pins
Pin Type
Pin Configuration
Pin Configuration
Package Type
Number of pins
A:
A: SOT23-6
F: 6
1: OUT-
2: GND
3: IN
4: SD
5: VDD
6: OUT+
Part Number
Marking
Package Type
SOT23-6
Standard Package
PAM8301AAF
FPXYW
3,000 Units/Tape & Reel
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
10
PAM8301
Filterless Class-D Mono Audio Amplifier
Outline Dimensions
SOT23-6
D
e
A
A
e1
SEE VVIIEEWWSS
b
WITH PLANTING
BASE MMEETTAALL
SECTION AA--AA
GAUGE PPLLAANNEE
SSEEAATTIINNGG PPLLAANNEE
L
L1
VIEW BB
Symbol
A
A1
A2
b
c
D
E
Spec 1.20 0.25 0.10 0.05 1.10 0.2 0.40 0.1 0.15 0.07 2.90 0.1 2.80 0.2
Symbol
Spec
E1
e
e 1
L
L1
θ
1.60 0.1 0.95BSC 1.90BSC 0.55 0.25 0.60REF
4° 4°
Unit: Millimeter
Power Analog Microelectronics,Inc
www.poweranalog.com
09/2008 Rev 1.2
11
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