PAM8302 [ETC]
Tiny Package 2 Watt Class-D Audio Amplifiers With Enable; 微型封装2瓦D类音频放大器，带有使能
| 型号： | PAM8302 |
| 厂家： | 
ETC |
| 描述： | Tiny Package 2 Watt Class-D Audio Amplifiers With Enable |
| 文件： | 总8页 (文件大小：189K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
PAM8302
Tiny Package 2 Watt Class-D Audio Amplifiers With Enable
FEATURES
DESCRIPTION
The PAM8302 is a 2 Watt, 8-pin, class D audio
amplifier with Enable function, it offers low THD+N
(0.10%), allowing it to produce high-quality sound
reproduction.
2 Watts @ 10% THD output into a 4 load at 5V
Support speakers or earphone (4 to 32 ).
With Enable function.
Superior low noise without input.
Supply voltage from 2.5V to 5.5V.
85% efficiency above.
The PAM8302 runs off of a 5 Volt supply at much
higher efficiencies than their class AB cousins,
making it ideal for many portable applications.
Short Circuit Protection.
Less output capacitor and inductor to save the
space and cost.
The PAM8302 only requires very few external
components (as few as two tiny capacitors), results
in significant cost and board space savings.
Low THD+N
Low quiescent current < 10 mA
The PAM8302 is available in a SOP8 package.
APPLICATIONS
Notebook Computers.
PDAs/ GPS Navigator/ e-Dictionary
Portable DVD Players, Game Machines.
Cellular Phones, VoIP Phones, Screen Phones
MP3 or PMP Players.
Portable Speaker System, Portable Amplifier
LCD monitor / TV.
Bluetooth Car-Kit
TYPICAL APPLICATION CIRCUIT
Vdd
33 H
VDD
0.47 F 10K
0.47 F
+OUT
Speaker
Input
IN
33 H
Enable
-OUT
0.47 F
GND
Power Analog Microelectronics, Inc.
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1
PAM8302 data sheet, Rev. 0.1
CONFIDENTIAL INFORMATION
PAM8302
Tiny Package 2 Watt Class-D AudioAmplifiers With Enable
Absolute Maximum Ratings:
TOP MARKING & PIN CONFIGURATION
Supply voltage: *6V
Input voltage: -0.3V to VDD +0.3V
O
O
Operation Temperature range: 40 C to 85 C
8
7
6
5
O
O
Operation junction temperature: -40 C to 125 C
A Y WW
O
O
Storage Temperature: -65 C to 150 C
AYWW
Weekly
Year
Assembly Location
O
Maximum Junction Temperature: 150 C
O
Soldering temperature: 250 C, 10 secretary
1
2
3
4
Recommended operating Conditions:
SOP8
Supply voltage Range: 2.5V to 5.5V
O
O
Operation Temperature Range: -40 C to 85 C
O
O
Junction Temperature Range: -40 C to 125 C
Pin Description
Thermal Information:
Description
Pin No.
Pin Name
Thermal Resistance (
):
JC
Right channel audio input.
IN_R
O
1
SOP8:
DIP8
90 C/W
JA
Supply voltage, need a 1uF ceramic
decouple capacitor very close bet
ween this pin to GND pin.
O
C/W
VDD
2
*Note: Without input signal.
Chip enable, high active.
GNDChip ground.
Not connected
3
4
5
6
7
8
EN
GND
NC
ORDERING INFORMATION
Chip ground.
GND
+OUT
-OUT
Ordering
Package Shipping
Non-inverted output
Inverted output
Number
2,500 Units/ Reel
PAM8302S8R SOP-8
ELECTRONIC SPECIFICATIONS
PARAMETER
CONDITION
MIN
TYP
MAX
UNITS
V
5
5.5
2.5
Vdd Range
Vdd Quiescent current
SW On Resistance
SW Frequency
Each channel
VDD = 5V
10
mA
0.4
500
-45
10
No Input Signal
kHz
dB
V/V
dB
K
PSRR
VDD = 2.5V to 5.5V
VDD = 2.5V to 5.5V, 0 input resistor
Gain
SNR
VDD = 5V, Po = 1.5W, 8 Load
60
Input impedance
100
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CONFIDENTIAL INFORMATION
PAM8302
Tiny Package 2 Watt Class-D Audio Amplifiers With Enable
BLOCK DIAGRAM
Vdd
C1
Input Signal
1
Bit
Speaker
1 F
Controller
Enable
Over Current
TEST CIRCUIT FOR GRAPHS
PAM8302 Demo Board
Load
+OUT
AP
Input
AP System One
Analyzer
AP System One
Generator
Low Pass
Filter
AUX-0025
-OUT
VDD
GND
Power Supply
Notes:
1.The APAUX-0025 low passfilter is necessaryfor every classD amplifier measurementdone by APanalyzer.
2.A 33 H inductor isused in serieswith load resistorto emulate thesmall speaker forefficiency measurement.
Power Analog Microelectronics, Inc.
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CONFIDENTIAL INFORMATION
PAM8302
Tiny Package 2 Watt Class-D Audio Amplifiers With Enable
(%)
100
50
(%)
100
Ap
Ap
50
20
10
20
10
5
5
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
(W)
(W)
THD+N vs. Output Power
8 , 1kHz, VDD = 5V
THD+N vs. Output Power
4 , 1kHz, VDD = 5V
(%)
Efficiency VS Output Power
100%
100
50
Ap
20
10
80%
60%
40%
20%
0%
5
2
1
0.5
0.2
0.1
0.05
0.02
0.01
0
1
2
3
(Hz)
5k 10k 20k
Power
20
50 100 200
500 1k 2k
Power Dissipation vs. Output Power
4 , 1kHz, VDD = 5V
THD+N vs. Frequency
8 , 500mW output, VDD = 5V
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
(dBr)
+0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
(Hz)
10k 20k
0
0.5
1
1.5
2
20
50 100 200
500 1k
2k
5k
Output Power -W
Power Dissipation vs. Output Power
FFT Noise Floor
(16k FFT)
4
, 1kHz, VDD = 5V
Class AB = Blue line
PAM8202 = Magenta line
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CONFIDENTIAL INFORMATION
PAM8302
Tiny Package 2 Watt Class-D Audio Amplifiers With Enable
OPERATION INFORMATION
Calculating Output Power of BTL amplifier
Output power is related to supply voltage and the saturation
voltage (Vsat). The Maximum peak-to-peak output voltage
on one side of BTL amplifier output is
Vsupply
Vsat
Vp-p = ( Vsupply - 2 X Vsat )
Vpk-pk
Vp-p
Vrms =
One side
2
2
Vsat
Vsupply
Maximum output power of a BTL amplifier with 1% THD is
2
Pout (1%) = 4 X Vrms / Rload
Maximum output power of a BTL amplifier with 10% THD is
Pout (10%) = Pout (1%) X 1.25
Output Power vs. Vp-p
BTL Output Power
5.0
4.0
3.0
2.0
1.0
0.0
4
8
0
1
2
3
4
5
6
Vdd - Vsat (V)
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CONFIDENTIAL INFORMATION
PAM8302
Tiny Package 2 Watt Class-D Audio Amplifiers With Enable
Vdd
C1
C2
33 H
VDD
0.47 F 10K
0.47 F
+OUT
Input
Speaker
IN
33 H
-OUT
Enable
0.47 F
GND
Fig. 1
Setting Amplifier voltage gain
It is very important to know the maximum output level (0dB) of the signal source connected to a power amplifier in
order to prevent hard clipping during operation.
Gain (max) = Vsupply/ Vin (p-p)
Insufficient voltage gain will cause low output level and maybe not enough to drive speaker properly. On the
other hand, the distortion will be very high if the voltage gain is too high in an audio system.
There is a 10k input resistor integrated in side IN (input) node, and since the integrated feedback resistor is 100k ,
so the maximum voltage gain of PAM8302 is limited at 10V/V (100k/10k, one output). With an external input resistor
(Rin) placed between signal source & input node, the voltage gain will be
Gain = 100k/ (10k + Rin) = Vsupply/ Vin (p-p)
Actual voltage gain is two times of this calculation because of BTL connection.
Decouple capacitor
PAM8302 is a high performance, high speed class D amplifier, and it requires a 1 F, X7R ceramic decouple
capacitor (C1) placed very close between VDD & GND pins to ensure the total harmonic distortion plus noise
(THD+N) performance is as designed. This is also very important for efficiency and lowering noise floor. Another
100 F to 1000 F main decouple capacitor (C2) should be placed close to supply pin for low frequency
Ecoupling.
Input capacitor
Input capacitor (Cin) blocks the DC voltage between signal source & amplifier to ensure the DC balancing will not
be broken between two systems. It also form a high-pass-filter (HPF) with input resistors (Rin + 10k), the lower corner
frequency (FCL) is determine by equation below.
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CONFIDENTIAL INFORMATION
PAM8302
Tiny Package 2 Watt Class-D Audio Amplifiers With Enable
FCL = 1/ [2 X Cin X (Rin + 10k)]
FCL is the lower corner on frequency response curve.
Cin is very important consider to the lower frequency performance. The Cin should not be too large with small
speakers as the load, because such small speakers usually can not response with lower frequency, delivering too
much low frequency energy into a small speaker which usually got resonant frequency (Fs) around 150Hz is
meaningless and dangerous. This will easily over drive the small speakers. The movement of speaker cone will be
too much under such condition and this also creates unnecessary distortion on mid-to high frequency range
because the speaker is now operating in non-linear area. Speakers can only generate heat but not low frequency
sound when it is over driven, the will cause speaker or amplifier failure in some cases.
Cin should have 10% tolerance or less because the tolerance can cause the input impedance mismatch at FCL
and below.
Output filter
The L and C on each output node of PAM8302 form the low-pass-filter (LPF), the higher corner frequency (FCH) is
determine by equation below.
FCH = 1/ [2 X sqr (L X C)]
FCH is the higher corner on frequency response curve.
Important Notice
The L-C filters (-12dB/Oct) gives twice much attenuation and lower impedance (means lower insertion loss)
compare to those R-C filters (-6dB), but remember, the FCH above is also the resonant frequency of this LC
network. The quality factor (Q) of this resonant network can be very high, depended on the Q of L and C. The high
resonant Q which is usually caused by open-load can generate a very high voltage on speaker terminal, and the
impedance of the L-C network can be very low, thus induces large amount of current flows from output stage of
PAM8302. This always causes part failure. So Do Not test open-load on any class D amplifier with output filters.
LC filter calculator with output load impedance and cut-off frequency
1
2 fC
1
f =
, X = 2 fL , X =
L C
2
LC
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CONFIDENTIAL INFORMATION
PAM8302
Tiny Package 2 Watt Class-D AudioAmplifiers With Enable
OUTLINE DIMENSION
SOP8
5.80 - 6.20
0.35 - 0.49
1.27 TYP.
3.80 - 4.00
4.80 - 5.00
45
1.35 - 1.75
0.19 - 0.25
0 ~ 8
0 - 0.15
0.40 - 0.90
Note: Package outline exclusive of mold flash and metal burr.
Power Analog Microelectronics, Inc.
CONFIDENTIAL. DO NOT DISTRIBUTE OR REPRODUCE WITHOUT PERMISSION FROM P.A.M.
CONFIDENTIAL INFORMATION
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