LM4811G-SM2-R [UTC]
DUAL 105mW HEADPHONE AMPLIFIER WITH DIGITAL VOLUME CONTROL AND SHUTDOWN MODE; 双105MW耳机放大器,具有数字音量控制和关闭模式型号: | LM4811G-SM2-R |
厂家: | Unisonic Technologies |
描述: | DUAL 105mW HEADPHONE AMPLIFIER WITH DIGITAL VOLUME CONTROL AND SHUTDOWN MODE |
文件: | 总9页 (文件大小:204K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
UNISONIC TECHNOLOGIES CO., LTD
LM4811
Preliminary
CMOS IC
DUAL 105mW HEADPHONE
AMPLIFIER WITH DIGITAL
VOLUME CONTROL AND
SHUTDOWN MODE
DESCRIPTION
The UTC LM4811 is a dual audio power amplifier with digital
volume control and shutdown mode function. It is featured in
unity-gain stability. The digital volume control sets the amplifier’s
gain from +12dB to -33dB in 16 discrete steps using a two-wire
interface. The shutdown mode is externally controlled, active-high
and micropower consumption. An internal thermal shutdown
protection circuit is contained in the device.
Operating on a 5V power supply, it can drive 16Ω load at
105mW per channel of continuous average power with 0.1%
(THD+N).
This device is mainly used to provide customers with higher
quality output power but less required external components. The
UTC LM4811 reduces the use of bootstrap capacitors or snubber
networks that make making it ideal for low-power portable systems
applications.
The UTC LM4811 is generally applied in cellular phones, MP3,
CD, DVD players, PDA’s and other portable electronics.
FEATURES
* Digital volume control range: +12dB~ -33dB
* "Click and Pop" suppression circuitry
* Saving the use of bootstrap capacitors
* Low shutdown current
ORDERING INFORMATION
Ordering Number
Lead Free
Package
Packing
Tape Reel
Halogen Free
LM4811G-SM2-R
LM4811L-SM2-R
MSOP-10
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LM4811
Preliminary
CMOS IC
PIN CONFIGURATION
Top View
VOUT1
VIN1
10
9
1
2
3
4
5
VDD
VOUT2
Bypass
VIN2
8
SHUTDOWN
UP/DN
CLOCK
GND
7
6
MSOP-10
PIN DESCRIPTION
PIN NO.
PIN NAME
VOUT1
DESCRIPTION
1
2
3
4
5
6
Channel 1 output
VIN1
Channel 1 audio input
Bypass
CLOCK
GND
Connect to internal voltage divider for middle supply bias
External clock input for the volume control
Ground
UP/DN
Volume UP/DOWN control
Shutdown mode control input, high active, place LM4811 into shutdown
mode, when held high
7
SHUTDOWN
8
9
VIN2
VOUT2
VDD
Channel 2 audio input
Channel 2 output
10
Supply voltage
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LM4811
Preliminary
CMOS IC
BLOCK DIAGRAM
VDD
10
VIN1
2
VDD
-
1
9
Shutdown 7
BIAS
VOUT1
50kΩ
50kΩ
+
20kΩ
20kΩ
3
Bypass
+
-
VOUT2
VIN2
8
6
4
UP/DN
Clock
Digital Volume
Control
5
GND
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LM4811
Preliminary
CMOS IC
ABSOLUTE MAXIMUM RATING (TC = 25°C, unless otherwise specified)
PARAMETER
SYMBOL
VCC
RATINGS
6.0
UNIT
V
Supply Voltage
Junction Temperature
Storage Temperature
TJ
150
℃
TSTG
-65~ +150
℃
Notes: 1. Absolute maximum ratings are those values beyond which the device could be permanently damaged.
Absolute maximum ratings are stress ratings only and functional device operation is not implied.
THERMAL DATA
PARAMETER
SYMBOL
θJA
RATINGS
194
UNIT
°C/W
°C/W
Junction to Ambient
Junction to Case
θJC
52
OPERATING RATINGS
PARAMETER
SYMBOL
VCC
RATINGS
2.0 ~ 5.5
-40 ~ 85
UNIT
V
Supply Voltage
Operating Temperature
TA
°C
ELECTRICAL CHARACTERISTICS (TA=25°C, unless otherwise specified) (Note 4, 5)
For VDD=5V
PARAMETER
SYMBOL
VDD
TEST CONDITIONS
MIN TYP MAX UNIT
Supply Voltage
2.0
5.5
3.0
V
Supply Current
IDD
VIN=0V, IO=0A
1.3
0.3
4.0
105
70
mA
μA
Shutdown Current
Output Offset Voltage
ISD
VIN=0V
VIN=0V
VOS
50
mV
mW
mW
%
RL=16Ω
RL=32Ω
Output Power
PO
THD+N=0.1%, f=1kHz
Total Harmonic Distortion
Channel Separation
THD+N PO=50mW, RL=32Ω, f=20Hz~20kHz
Crosstalk RL=32Ω, f=1kHz, PO=70mW
0.3
100
dB
CB=1.0μF,VRIPPLE=100mVPP
f=217Hz
,
Power Supply Rejection Ratio
PSRR
60
dB
Input Voltage
(Clock, UP/DN, Shutdown)
High
Low
VIH
VIL
1.4
V
0.4
V
Input referred minimum gain
Input referred maximum gain
All 16 discrete steps
-33
+12
3.0
dB
dB
dB
dB
Digital Volume Range
Digital Volume Stepsize
Stepsize Error
All 16 discrete steps
±0.3
Channel-to-Channel Volume
Tracking Error
All gain settings from -33dB ~ +12dB
Shutdown mode active
0.15
-100
dB
dB
Shutdown Attenuation
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LM4811
Preliminary
CMOS IC
ELECTRICAL CHARACTERISTICS(Cont.)
For VDD=3.3V
PARAMETER
SYMBOL
IDD
ISD
TEST CONDITIONS
MIN TYP MAX UNIT
Supply Current
VIN=0V, IO=0A
VIN=0V
1.1
0.3
4.0
40
mA
μA
Shutdown Current
Output Offset Voltage
VOS
VIN=0V
mV
mW
mW
%
RL=16Ω
RL=32Ω
Output Power
PO
THD+N=0.1%, f=1kHz
28
Total Harmonic Distortion
Power Supply Rejection Ratio
THD+N PO=25mW, RL=32Ω, f=20Hz~20kHz
0.5
CB=1.0μF,VRIPPLE=100mVPP
,
PSRR
60
dB
f=217Hz
Input Voltage
(Clock, UP/DN, Shutdown)
High
VIH
VIL
1.4
V
Low
0.4
V
Input referred minimum gain
Input referred maximum gain
All 16 discrete steps
-33
+12
3.0
dB
dB
dB
dB
Digital Volume Range
Digital Volume Stepsize
Stepsize Error
All 16 discrete steps
±0.3
Channel-to-Channel Volume
Tracking Error
All gain settings from -33dB ~ +12dB
Shutdown mode active
0.15
-100
dB
dB
Shutdown Attenuation
For VDD=2.6V
PARAMETER
SYMBOL
IDD
TEST CONDITIONS
VIN=0V, IO=0A
VIN=0V
MIN TYP MAX UNIT
Supply Current
Shutdown Current
Output Offset Voltage
1.0
0.3
4.0
20
mA
μA
ISD
VOS
VIN=0V
mV
mW
mW
%
RL=16Ω
THD+N=0.1%, f=1kHz
RL=32Ω
Output Power
PO
16
Total Harmonic Distortion
Power Supply Rejection Ratio
THD+N PO=15mW, RL=32Ω, f=20Hz~20kHz
0.6
CB=1.0μF,VRIPPLE=100mVPP
,
PSRR
60
dB
f=217Hz
Input Voltage
(Clock, UP/DN, Shutdown)
High
VIH
VIL
1.4
V
Low
0.4
V
Input referred minimum gain
Input referred maximum gain
All 16 discrete steps
-33
+12
3.0
dB
dB
dB
dB
Digital Volume Range
Digital Volume Stepsize
Stepsize Error
All 16 discrete steps
±0.3
Channel-to-Channel Volume
Tracking Error
All gain settings from -33dB ~ +12dB
0.15
dB
dB
Shutdown Attenuation
Shutdown mode active
-75
Notes: 4. Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.
5. All voltages are measured with respect to the ground pin, unless otherwise specified.
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LM4811
Preliminary
CMOS IC
APPLICATION INFORMATION
DIGITAL VOLUME CONTROL
The UTC LM4811 is dual audio power amplifier with digital volume control and shutdown mode function. The
CLOCK pin is drived by an external clock. It’ s gain is controlled by the signals applied to the CLOCK and UP/DN
inputs.
The audio power amplifier’s gain is fixed by the signals, which are applied to the CLOCK and UP/DN inputs. The
gain is controlled by the logic voltage level applied to the UP/DN pin at each rising edge of the clock signal. At each
rising edge of the clock signal, when a logic high voltage level is applying to the UP/DN pin, 3dB is increased, in
verse when a logic low voltage is applying to the UP/DN pin, 3dB is decreased on the contrary. For both the CLOCK
and UP/DN inputs, the trigger point is 1.4V (MIN.) for a logic high level, and 0.4V (MAX.) for a logic low level.
The UTC LM4811 contains16 discrete gain settings varying from +12dB (MAX.) to -33dB (MIN.), amplifier’s gain
is set to a default value of 0dB during power on condition. However, when coming out of shutdown mode, the UTC
LM4811 will revert back to its previous gain setting.
In order to avoid undesired state changes during transitions between VIL and VIH, the UTC LM4811’s CLOCK
and UP/DN pins should be debounced. This will ensure correct operation of the digital volume control. A
microcontroller or microprocessor output is expected to drive the CLOCK and UP/DN pins.
1
UP/DN
0
1
CLOCK
0
VOLUME
Default
Down
Up
Down
Up
Figure 2. Timing Diagram
POWER SUPPLY BYPASSING
To obtain low noise performance and high power supply rejection, proper supply bypassing is essentially
needed for any power amplifier. Capacitor on both the bypass and power supply pins should be placed closely as
possible. Bypass capacitor value is also critical as it directly affects the device’s half-supply voltage stability and
PSRR. The stability and supply rejection increase as the bypass capacitor’s value increases. In the typical
applications, employing a 5V regulator with 10μF and a 0.1μF bypass capacitors which aid in supply stability. This,
however, is not saving the need for bypassing the supply nodes of the UTC LM4811. The issue of selecting bypass
capacitors, especially CB, is thus dependent upon desired low frequency PSRR, click and pop performance, system
cost, and size constraints.
SHUTDOWN FUNCTION
The UTC LM4811 contains a bias circuitry shutdown to reduce power consumption while not is use. By applying
a logic high to the SHUTDOWN pin, the shutdown function is active. For a logic high level, the trigger point is 1.4V
(MIN.), and 0.4V (MAX.) for a logic low. For a better shutdown performance, it is best to switch between ground and
VDD. By switching the SHUTDOWN pin to VDD, the UTC LM4811 supply current draw will be minimized in idle mode.
Whereas the device will be disabled with shutdown voltages less than VDD, the idle current may be greater than
0.3μA (TYP.). In either case, the SHUTDOWN pin should be tied to a fixed voltage to avoid undesired state changes.
In many applications, a microcontroller or microprocessor output is used to control the shutdown circuitry. This
provides a quick, smooth shutdown transition. Another solution is to use a single-pole, single-throw switch in
conjunction with an external pull-up resistor. When the switch is closed, the SHUTDOWN pin is connected to ground
and enables the amplifier. If the switch is open, the external pull-up resistor, RPU, will disable the UTC LM4811. This
scheme guarantees that the SHUTDOWN pin will not float, thus preventing undesired state changes.
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LM4811
Preliminary
CMOS IC
APPLICATION INFORMATION(Cont.)
PROPER SELECTION OF EXTERNAL COMPONENTS
In applications, selection of external components when using integrated power amplifiers is critical for optimum
device and system performance. Moreover, the vales of external components are also important to consider as they
directly affect the overall system quality. The UTC LM4811 is tolerant to a variety external component combinations.
The UTC LM4811 is unity-gain stable, providing designers maximize system performance. Low gain settings
maximize signal-to-noise performance and minimizes THD+N. Low gain configurations require large input signals to
obtain a given output power. Input signals reach 1Vrms or higher are available from sources such as audio codecs.
SELECTION OF INPUT AND OUTPUT CAPACITOR SIZE
Another consideration is the closed loop bandwidth besides gain. To a large extent, the bandwidth is dicated by
the choice of external components shown in Figure 1. Both the CI (input coupling capacitor) and the CO (output
coupling capacitor) form first order high pass filters which limit low frequency response. The values of these
capacitors should be based on the desired frequency response weighed against the following:
Large value input and output capacitors are both expensive and space consuming for portable designs. Clearly
a certain sized capacitor is needed to couple in low frequencies without severe attenuation. But in many cases the
speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 150Hz.
Thus large input and output capacitors may not increase system performance.
Moreover, for the system cost and size, click and pop performance is affected by the size of the CI (input
coupling capacitor). A larger input coupling capacitor requires more charge to reach its quiescent DC voltage
(nominally 1/2 VDD ). This charge comes from the output via the feedback and the pops are apt to be generated upon
device enable. Reducing the value of input coupling capacitor can minimize the turn on pops, which is based on
necessary low frequency response.
The value of bypass capacitor should be taken into consideration besides minimizing the input and output
capacitor values. For minimizing turn on pops, the bypass capacitor CB plays the most important role, since it
determines how fast the UTC LM4811 turns on. The slower the UTC LM4811’s outputs ramp to their quiescent DC
voltage (nominally 1/2 VDD ), the smaller the turn on pop. While the device will function properly, (no oscillations or
motorboating), with CB equal to 1μF, the device will be much more susceptible to turn on clicks and pops. Thus, a
value of CB equal to 1μF or larger is recommended in all but the most cost sensitive designs.
In addition, the type of capacitors should be given enough consideration since different types of capacitors
(tantalum, electrolytic, ceramic) have unique performance characteristics and may affect overall system
performance.
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LM4811
Preliminary
CMOS IC
TYPICAL APPLICATION CIRCUIT
VDD
CS
+
1μF
CI
1μF
VIN1
+
Audio
Input
VDD
VDD
50kΩ
-
RPU
100kΩ
VOUT1
+
Shutdown
CO
100μF
+
BIAS
20kΩ
20kΩ
Bypass
+
CB
+
-
50kΩ
VOUT2
+
1μF
CO
100μF
CI
1μF
VIN2
+
Audio
Input
UP/DN
Clock
Digital Volume
Control
VDD
GND
VDD
RP
100Ω
RPD
100Ω
CP
0.1μF
* 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
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LM4811
Preliminary
CMOS IC
EXTERNAL COMPONENTS DESCRIPTION
PIN NO.
PIN NAME
DESCRIPTION
This is the input coupling capacitor. It blocks the DC voltage at, and couples the input
signal to, the amplifier’s input terminals. C also creates a highpass filter with the internal
input resistor, RI, at fC =1/(2πRICI). The minimum value of RI is 33kΩ. Refer to the
section, Proper Selection of External Components, for an explanation of how to
determine the value of CI.
1
2
CI
This is the supply bypass capacitor. It provides power supply filtering. Refer to the
Application Information section for proper placement and selection of the supply
bypass capacitor.
CS
This is the BYPASS pin capacitor. It provides half-supply filtering. Refer to the section,
Proper Selection of External Components, for information concerning proper
placement and selection of CB.
3
4
CB
CO
This is the output coupling capacitor. It blocks the DC voltage at the amplifier’s output
and it forms a high pass filter with RL at fO = 1/(2πRLCo )
UTC assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or
other parameters) listed in products specifications of any and all UTC products described or contained
herein. UTC products are not designed for use in life support appliances, devices or systems where
malfunction of these products can be reasonably expected to result in personal injury. Reproduction in
whole or in part is prohibited without the prior written consent of the copyright owner. The information
presented in this document does not form part of any quotation or contract, is believed to be accurate
and reliable and may be changed without notice.
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