HWD2182 [ETC]
250mW Audio Power Amplifier with Shutdown Mode; 250mW的音频功率放大器关断模式
| 型号： | HWD2182 |
| 厂家： | 
ETC |
| 描述： | 250mW Audio Power Amplifier with Shutdown Mode |
| 文件： | 总12页 (文件大小：598K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
HWD2182
250mW Audio Power Amplifier with Shutdown Mode
General Description
Key Specifications
The HWD2182 is a single-ended audio power amplifier ca-
pable of delivering 250mW of continuous average power into
an 8Ω load with 1% THD+N from a 5V power supply.
j
THD+N at 1kHz at 250mW
continuous average output
power into 8Ω
1.0% (max)
audio power amplifiers were designed specifically
to provide high quality output power with a minimal amount
of external components using surface mount packaging.
Since the HWD2182 does not require bootstrap capacitors or
snubber networks, it is optimally suited for low-power por-
table systems.
j
j
Output Power at 1% THD+N
at 1kHz into 4Ω
380mW (typ)
THD+N at 1kHz at 85mW
continuous average output
power into 32Ω
0.1% (typ)
0.7µA (typ)
The HWD2182 features an externally controlled, low power
consumption shutdown mode which is virtually clickless and
popless, as well as an internal thermal shutdown protection
mechanism.
j
Shutdown Current
Features
n MSOP surface mount packaging
n “Click and Pop” Suppression Circuitry
n Supply voltages from 2.4V–5.5V
n Operating Temperature −40˚C to 85˚C
n Unity-gain stable
The unity-gain stable HWD2182 can be configured by external
gain-setting resistors.
n External gain configuration capability
n No bootstrap capacitors, or snubber circuits are
necessary
Applications
n Personal Computers
n Cellular Phones
n General Purpose Audio
Typical Application
Connection Diagram
MSOP and SOIC Package
Top View
Order Number HWD2182MM or HWD2182M
*Refer to the Application Information Section for information concerning
proper selection of the input and output coupling capacitors.
FIGURE 1. Typical Audio Amplifier Application Circuit
1
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the CSMSC Semiconductor Sales Office/
Distributors for availability and specifications.
See AN-450 ″Surface Mounting and their Effects on
Product Reliability″ for other methods of soldering surface
mount devices.
Thermal Resistance
θJC (MSOP)
θJA (MSOP)
θJC (SOP)
θJA (SOP)
56˚C/W
210˚C/W
35˚C/W
Supply Voltage
6.0 V
−65˚C to +150˚C
−0.3V to VDD + 0.3V
Internally limited
2000V
Storage Temperature
Input Voltage
170˚C/W
Power Dissipation (Note 3)
ESD Susceptibility (Note 4)
PIn 5
Operating Ratings
1500V
Temperature Range
Junction Temperature
150˚C
TMIN ≤ TA ≤ TMAX
−40˚C ≤ TA ≤ 85˚C
2.4V ≤ VDD ≤ 5.5V
Soldering Information
Small Outline Package
Supply Voltage
Vapor Phase (60 seconds)
Infrared (15 seconds)
215˚C
220˚C
Electrical Characteristics (Notes 1, 2)
The following specifications apply for VDD = 5V unless otherwise specified. Limits apply for TA = 25˚C.
HWD2182
Typical Limit
Units
(Limits)
Symbol
Parameter
Conditions
(Note 5)
(Note 6)
IDD
Quiescent Current
VIN = 0V, IO = 0A
2
0.5
5
4.0
5
mA (max)
µA (max)
mV (max)
ISD
Shutdown Current
Offset Voltage
Output Power
Vpin1 = VDD
VOS
P O
VIN = 0V
50
THD + N = 1% (max); f = 1 kHz;
RL = 4Ω
380
270
95
mW
mW (min)
mW
RL = 8Ω
250
RL = 32Ω
THD + N = 10%; f = 1 kHz
RL = 4Ω
480
325
125
0.5
mW
mW
mW
%
RL = 8Ω
RL = 32Ω
THD + N
PSRR
Total Harmonic Distortion + Noise
Power Supply Rejection Ratio
RL = 8Ω, P = 250 mWrms;
O
RL = 32Ω, PO = 85 mWrms;
0.1
%
f = 1 kHz
Vpin3 = 2.5V, V
f = 120 Hz
= 200 mVrms,
ripple
50
dB
Electrical Characteristics (Notes 1, 2)
The following specifications apply for VDD = 3V unless otherwise specified. Limits apply for TA = 25˚C.
HWD2182
Units
(Limits)
Symbol
Parameter
Conditions
Typical
Limit
(Note 5)
(Note 6)
IDD
Quiescent Current
VIN = 0V, IO = 0A
1.2
0.3
5
mA
µA
ISD
Shutdown Current
Offset Voltage
Output Power
Vpin1 = VDD
VOS
P O
VIN = 0V
mV
THD + N = 1% (max); f = 1 kHz
RL = 8Ω
80
30
mW
mW
RL = 32Ω
THD + N = 10%; f = 1 kHz
RL = 8Ω
105
40
mW
mW
RL = 32Ω
2
Electrical Characteristics (Notes 1, 2) (Continued)
The following specifications apply for VDD = 3V unless otherwise specified. Limits apply for TA = 25˚C.
HWD2182
Units
(Limits)
Symbol
Parameter
Conditions
Typical
Limit
(Note 6)
(Note 5)
THD + N
Total Harmonic Distortion + Noise
RL = 8Ω, P = 70 mWrms;
0.25
%
%
O
RL = 32Ω, PO = 30 mWrms;
0.3
f = 1 kHz
PSRR
Power Supply Rejection Ratio
Vpin3 = 2.5V, V
f = 120 Hz
= 200 mVrms,
ripple
50
dB
Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func-
tional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guar-
antee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is
given, however, the typical value is a good indication of device performance.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
, θ , and the ambient temperature T . The maximum
A
JMAX JA
allowable power dissipation is P
= (T
− T )/θ . For the HWD2182, T
= 150˚C, and the typical junction-to-ambient thermal resistance, when board
JMAX
DMAX
JMAX
A
JA
mounted, is 210˚C/W for the MUA08A Package and 170˚C/W for the M08A Package.
Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 5: Typicals are measured at 25˚C and represent the parametric norm.
External Components Description
(Refer to Figure 1)
Components
Functional Description
1. Ri
Inverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a
high pass filter with Ci at fc = 1 / (2πRiCi).
2. Ci
Input coupling capacitor which blocks the DC voltage at the amplifier’s input terminals. Also creates a
highpass filter with Ri at fc = 1 / (2πRiC ). Refer to the section, Proper Selection of External Components,
i
for an explanation of how to determine the values of Ci.
3. Rf
Feedback resistance which sets closed-loop gain in conjunction with Ri.
4. CS
Supply bypass capacitor which provides power supply filtering. Refer to the Application Information section
for proper placement and selection of the supply bypass capacitor.
5. CB
6. CO
Bypass pin capacitor which provides half-supply filtering. Refer to the section, Proper Selection of External
Components, for information concerning proper placement and selection of CB.
Output coupling capacitor which blocks the DC voltage at the amplifier’s output. Forms a high pass filter wth
RL at fO = 1 / (2πRLC O).
Typical Performance Characteristics
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
3
Typical Performance Characteristics (Continued)
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
THD+N vs
Output Power
THD+N vs
Output Power
THD+N vs
Output Power
4
Typical Performance Characteristics (Continued)
THD+N vs
Output Power
THD+N vs
Output Power
THD+N vs
Output Power
THD+N vs
Output Power
THD+N vs
Output Power
Output Power vs
Supply Voltage
Output Power vs
Supply Voltage
Output Power vs
Supply Voltage
5
Typical Performance Characteristics (Continued)
Dropout Voltage vs
Supply Voltage
Dropout Voltage vs
Supply Voltage
Power Supply
Rejection Ratio
Output Power vs
Load Resistance
Power Dissipation vs
Output Power
Supply Current vs
Supply Voltage
6
Typical Performance Characteristics (Continued)
Open Loop
Frequency Response
Output Attenuation in
Shutdown Mode
Noise Floor
Frequency Response
vs Output Capacitor Size
Frequency Response
vs Output Capacitor Size
Frequency Response
vs Input Capacitor Size
Typical Application
Frequency Response
Typical Application
Frequency Response
Power Derating Curve
7
displayed in the Typical Performance Characteristics sec-
tion, the effect of a larger half supply bypass capacitor is im-
proved low frequency PSRR due to increased half-supply
stability. Typical applications employ a 5V regulator with
10 µF and a 0.1 µF bypass capacitors which aid in supply
stability, but do not eliminate the need for bypassing the sup-
ply nodes of the HWD2182. The selection of bypass capaci-
tors, especially CB, is thus dependent upon desired low fre-
quency PSRR, click and pop performance as explained in
the section, Proper Selection of External Components
section, system cost, and size constraints.
Application Information
SHUTDOWN FUNCTION
In order to reduce power consumption while not in use, the
HWD2182 contains a shutdown pin to externally turn off the
amplifier’s bias circuitry. This shutdown features turns the
amplifier off when a logic high is placed on the shutdown pin.
The trigger point between a logic low and logic high level is
typically half supply. It is best to switch between ground and
supply to provide maximum device performance. By switch-
ing the shutdown pin to the VDD, the HWD2182 supply current
draw will be minimized in idle mode. While the device will be
disabled with shutdown pin voltages less than V DD, the idle
current may be greater than the typical value of 0.5 µA. In ei-
ther case, the shutdown pin should be tied to a definite volt-
age because leaving the pin floating may result in an un-
PROPER SELECTION OF EXTERNAL COMPONENTS
Selection of external components when using integrated
power amplifiers is critical to optimize device and system
performance. While the HWD2182 is tolerant of external com-
ponent combinations, consideration to component values
must be used to maximize overall system quality.
wanted shutdown condition. In many applications,
a
microcontroller or microprocessor output is used to control
the shutdown circuitry which provides a quick smooth transi-
tion into shutdown. Another solution is to use a single-pole,
single-throw switch in conjunction with an external pull-up re-
sistor. When the switch is closed, the shutdown pin is con-
nected to ground and enables the amplifier. If the switch is
open, then the external pull-up resistor will disable the
HWD2182. This scheme guarantees that the shutdown pin will
not float which will prevent unwanted state changes.
The HWD2182 is unity gain stable and this gives a designer
maximum system flexibility. The HWD2182 should be used in
low gain configurations to minimize THD+N values, and
maximize the signal to noise ratio. Low gain configuartions
require large input signals to obtain a given output power. In-
put signals equal to or greater than 1 Vrms are available
from sources such as audio codecs. Please refer to the sec-
tion, Audio Power Amplifier Design, for a more complete
explanation of proper gain selection.
POWER DISSIPATION
Besides gain, one of the major considerations is the closed
loop bandwidth of the amplifier. To a large extent, the band-
width is dictated by the choice of external components
shown in Figure 1. Both the input coupling capacitor, Ci, and
the output coupling capacitor, Co, form first order high pass
filters which limit low frequency response. These values
should be chosen based on needed frequency response for
a few distinct reasons.
Power dissipation is a major concern when using any power
amplifier and must be thoroughly understood to ensure a
successful design. Equation 1 states the maximum power
dissipation point for a single-ended amplifier operating at a
given supply voltage and driving a specified output load.
PDMAX = (VDD
)
2/(2π2RL)
(1)
Even with this internal power dissipation, the HWD2182 does
not require heat sinking over a large range of ambient tem-
perature. From Equation 1, assuming a 5V power supply and
an 4Ω load, the maximum power dissipation point is
316 mW. The maximum power dissipation point obtained
must not be greater than the power dissipation that results
from Equation 2:
CLICK AND POP CIRCUITRY
The HWD2182 contains circuitry to minimize turn-on and turn-
off transients or “clicks and pops.” In this case, turn-on refers
to either power supply turn-on or the device coming out of
shutdown mode. When the device is turning on, the amplifi-
ers are internally muted. An internal current source ramps up
the voltage of the bypass pin. Both the inputs and outputs
track the voltage at the bypass pin. The device will remain
muted until the bypass pin has reached its half supply volt-
age, 1/2 VDD. As soon as the bypass node is stable, the de-
vice will become fully operational, where the gain is set by
the external resistors.
PDMAX = (TJMAX−T A)/θJA
(2)
For the HWD2182 surface mount package, θ = 210˚C/W and
JA
TJMAX = 150˚C. Depending on the ambient temperature, TA,
of the system surroundings, Equation 2 can be used to find
the maximum internal power dissipation supported by the IC
packaging. If the result of Equation 1 is greater than that of
Equation 2, then either the supply voltage must be de-
creased, the load impedance increased or T A reduced. For
the typical application of a 5V power supply, with an 4Ω load,
the maximum ambient temperature possible without violating
the maximum junction temperature is approximately 83˚C
provided that device operation is around the maximum
power dissipation point. Power dissipation is a function of
output power and thus, if typical operation is not around the
maximum power dissipation point, the ambient temperature
may be increased accordingly. Refer to the Typical Perfor-
mance Characteristics curves for power dissipation infor-
mation for lower output powers.
Although the bypass pin current source cannot be modified,
the size of CB can be changed to alter the device turn-on
time and the level of “clicks and pops.” By increasing the
value of C B, the level of turn-on pop can be reduced. How-
ever, the tradeoff for using a larger bypass capacitor is an in-
crease in turn-on time for the device. There is a linear rela-
tionship between the size of CB and the turn-on time. Here
are some typical turn-on times for a given CB:
CB
TON
0.01 µF
0.1 µF
0.22 µF
0.47 µF
20 ms
200 ms
420 ms
900 ms
POWER SUPPLY BYPASSING
As with any power amplifier, proper supply bypassing is criti-
cal for low noise performance and high power supply rejec-
tion. The capacitor location on both the bypass and power
supply pins should be as close to the device as possible. As
In order to eliminate “clicks and pops,” all capacitors must be
discharged before turn-on. Rapid on/off switching of the de-
8
Extra supply voltage creates headroom that allows the
HWD2182 to reproduce peaks in excess of 300 mW without
clipping the signal. At this time, the designer must make sure
that the power supply choice along with the output imped-
ance does not violate the conditions explained in the Power
Dissipation section.
Application Information (Continued)
vice or the shutdown function may cause the “click and pop”
circuitry to not operate fully, resulting in increased “click and
pop” noise.
The value of Ci will also reflect turn-on pops. Clearly, a cer-
tain size for Ci is needed to couple in low frequencies without
excessive attenuation. But in many cases, the speakers
used in portable systems have little ability to reproduce sig-
nals below 100 Hz to 150 Hz. In this case, using a large input
and output coupling capacitor may not increase system per-
formance. In most cases, choosing a small value of Ci in the
range of 0.1 µF to 0.33 µF, along with CB equal to 1.0 µF
should produce a virtually clickless and popless turn-on. In
Once the power dissipation equations have been addressed,
the required gain can be determined from Equation 4.
(4)
AV = Rf / Ri
(5)
From Equation 4, the minimum gain is:
AV = 1.4
cases where C is larger than 0.33 µF, it may be advanta-
i
Since the desired input impedance was 20 kΩ, and with a
gain of 1.4, a value of 28 kΩ is designated for Rf, assuming
5% tolerance resistors. This combination results in a nominal
gain of 1.4. The final design step is to address the bandwidth
requirements which must be stated as a pair of −3 dB fre-
quency points. Five times away from a −3 dB point is 0.17 dB
down from passband response assuming a single pole roll-
off. As stated in the External Components section, both Ri
in conjunction with C i, and Co with RL, create first order high-
pass filters. Thus to obtain the desired frequency low re-
geous to increase the value of CB. Again, it should be under-
stood that increasing the value of CB will reduce the “clicks
and pops” at the expense of a longer device turn-on time.
AUDIO POWER AMPLIFIER DESIGN
Design a 250 mW/8Ω Audio Amplifier
Given:
Power Output
Load Impedance
Input Level
250 mWrms
8Ω
±
sponse of 100 Hz within 0.5 dB, both poles must be taken
into consideration. The combination of two single order filters
at the same frequency forms a second order response. This
results in a signal which is down 0.34 dB at five times away
from the single order filter −3 dB point. Thus, a frequency of
20 Hz is used in the following equations to ensure that the re-
sponse is better than 0.5 dB down at 100 Hz.
1 Vrms (max)
20 kΩ
Input Impedance
Bandwidth
±
100 Hz–20 kHz 0.50 dB
A designer must first determine the needed supply rail to ob-
tain the specified output power. Calculating the required sup-
ply rail involves knowing two parameters, VOPEAK and also
the dropout voltage. The latter is typically 530mV and can be
found from the graphs in the Typical Performance Charac-
teristics. VOPEAK can be determined from Equation 3.
Ci ≥ 1 / (2π * 20 kΩ * 20 Hz) = 0.397 µF; use 0.39 µF.
Co ≥ 1 / (2π * 8Ω * 20 Hz) = 995 µF; use 1000 µF.
The high frequency pole is determined by the product of the
desired high frequency pole, fH, and the closed-loop gain, A
V
. With a closed-loop gain of 1.4 and fH = 100 kHz, the result-
ing GBWP = 140 kHz which is much smaller than the
HWD2182 GBWP of 12.5Mhz. This figure displays that if a de-
signer has a need to design an amplifier with a higher gain,
the HWD2182 can still be used without running into bandwidth
limitations.
(3)
For 250 mW of output power into an 8Ω load, the required
VOPEAK is 2 volts. A minimum supply rail of 4.55V results
from adding VOPEAK and VOD. Since 5V is a standard supply
voltage in most applications, it is chosen for the supply rail.
9
Physical Dimensions inches (millimeters) unless otherwise noted
Order Number HWD2182
10
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Order Number HWD2182
11
Chengdu Sino Microelectronics System Co.,Ltd
(Http://www.csmsc.com)
Headquarters of CSMSC:
Beijing Office:
Address: 2nd floor, Building D,
Science & Technology
Industrial Park, 11 Gaopeng
Avenue, Chengdu High-Tech
Zone,Chengdu City, Sichuan
Province, P.R.China
Address: Room 505, No. 6 Building,
Zijin Garden, 68 Wanquanhe
Rd., Haidian District,
Beijing, P.R.China
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Tel: +86-28-8517-7737
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