NAU82011WG Datasheet Rev1.0 Page 1 of 16 Dec, 2012
NAU82011WG
2.9 W Mono Filter -Free Class-D Audio Amplifier
1 Description
The NAU82011WG is a mono high efficie ncy filter-free Class-D audio amplifier with variable gain, which is capable of
driving a 4Ω load with up to 2.9W output power. This device provides chip enable pin with extremely low standby
current and fast start-up time of 4ms.
The NAU82011WG is ideal for the porta ble app licatio ns of battery drive, as it has advanced features like 9 1% efficiency,
low quiescent current (i.e. 1.2mA at 3.6V) and superior EMI performance. It has the ability to configure the inputs in
either single-ended or differential mode.
NAU82011WG is available in MSOP-8 package.
Key Features
Low Quiescent Current:
• 1.2mA at 3.6V
• 1.7mA at 5V
Powerful Mono Class-D Amplifier:
• 2.9W (4Ω @ 5V, 10% THD+N)
• 2.3W (4Ω @ 5V, 1% THD+N)
• 1.7W (8Ω @ 5V, 10% THD+N)
• 1.38W (8Ω @ 5V, 1% THD+N)
Low Output Noise: 20 µVRMS
Low Current S hutdown M ode
Integrated Image Reject Filter
Click-and Pop Suppression
Integrated feedback resistor of 30 0 kΩ
• 1.48 W (4Ω @ 3.6V, 10% THD+N)
• 1.2 W (4Ω @ 3.6V, 1% THD+N)
• 0.88 W (8Ω @ 3.6V, 10% THD+N)
• 0.71 W (8Ω @ 3.6V, 1% THD+N)
Applications
Smartphones
Tablet PCs
Personal Navigation Devices
VDD
VSS
Current / Thermal
Protection
VIN Class D
Modulator Output
Driver
VIP
NAU82011WG
EN
Click / Pop
Suppression
R1
R1
Figure 1: NAU82011WG Block Diagram
NAU82011WG Datasheet Rev1.0 Page 2 of 16 Dec, 2012
2 Pin out
EN
NC
VIP
VIN
VOUTN
GND
VDD
VOUTP
2
3
4
1
7
6
5
8
NAU82011WG
Part Number Dimension Package Package Material
NAU82011WG 3mm x 3 mm MSOP-8 Green
3 Pin Descr iptions
Pin # Name Type Functionality
1
EN
Digital Input
Chip E nable (High = Power Up; Low = Power Down)
2
NC
NC
No Connection
3
VIP
Analog I nput
Positive Di fferential Input
4
VIN
Analog I nput
Negat ive Differe ntial Input
5
VOUTP
Analog Outp ut
Positive BTL Output
6
VDD
Supply
Power Supply
7
GND
Supply
High Current G round
8
VOUTN
Analog Outp ut
Negat ive BTL Outp ut
Table 1: NAU82011WG Pin descript i on
NAU82011WG Datasheet Rev1.0 Page 3 of 16 Dec, 2012
Electrica l Characteristics
Conditions: EN = VDD = 5V, VSS = 0V, Av = 6dB, ZL = ∞, unless otherwise specified, R1 = 150kΩ, Bandwidt h =
20Hz to 22 kHz, TA = 25 oC
Parameter
Comments/Conditions
Min
Max
Units
Power Delivered
Output Power Pout
Z
L
= 4Ω + 33µH
THD + N = 10%
VDD = 5.0V
W
VDD = 3.6V
Z
L
= 4Ω + 33µH
THD + N = 1%
VDD = 5.0V
VDD = 3.6V
Z
L
= 8Ω + 68µH
THD + N = 10%
VDD = 5.0V
VDD = 3.6V
Z
L
= 8Ω + 68µH
THD + N = 1%
VDD = 5.0V
VDD = 3.6V
Parameter
Symbol
Comments/Conditions
Min
Typ
Max
Units
Chip Enable (EN)
Voltage Enable High
VEN H
VDD = 2.5V to 5.5V
1.3
V
Voltage Enable Low
VEN L
VDD = 2.5V to 5.5V
0.35
V
Input Leakage C urrent
0.1
2.0
µA
Thermal and Current Protection
Ther mal Sh ut down Temp
150
oC
Ther mal Sh ut down Hystere s i s
20
oC
Over Current Threshold
IOC
2.0
A
Gain
A
V
VDD = 2.5V to 5.5V, R1
in kΩ
255/R1
300/R1
345/R1
V/V
Resistance (EN pin to GND)
REN
300
kΩ
NAU82011WG Datasheet Rev1.0 Page 4 of 16 Dec, 2012
Electrical Characte ristics (continued)
Conditions: EN = VDD = 5V, VSS = 0V, Av = 6dB, R1 = 150kΩ, ZL = ∞, unless otherwise specified, Bandwidth =
20Hz to 22 kHz, TA = 25 oC
Parameter
Symbol
Comments/Conditions
Min
Typ
Max
Units
Normal Oper a tion
Quiescent Current Consumption IQUI
VDD = 3.6V
1.2
mA
VDD = 5V
1.7
mA
Shut D own Current
IOFF
EN = 0
0.5
µA
Oscillator Frequency
fOSC
300
kHz
Efficiency
η
RL = 8Ω
91
%
Start Up Time
Tstart
4
msec
Output Offset Voltage
VOS
±1
mV
Common Mode Rejection Ratio
CMRR
fIN = 1kHz
63
dB
Click-and-Pop Suppression
1Hz Shutdo wn (ZL=8Ω)
83
dBV
Power Supply Reje ction Ratio PSRR
DC PSRR
95
dB
AC PSRR V
RIPPLE
=
0.2Vpp@1kHz
60
dB
Noise Performance
V
DD
= 3.6V (A-weighted)
20
µV
RMS
Absolute Maximum Ratings
Parameter Min Max Units
Analog supply -0.50 +5.50 V
Industrial operating temperature -40 +85 °C
Storage temperature range -65 +150 °C
Junct ion temperature range -40 +150 °C
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may
adversely influence product reliability and result in failures not covered by warranty.
NAU82011WG Datasheet Rev1.0 Page 5 of 16 Dec, 2012
Recommended Operating Conditions
Parameter Symbol Min Typical Max Units
Analo g sup p l y range VDD 2.50 5.00 5.50 V
Ground VSS 0 V
Input Resistor (Gain ≤ 26dB ) R1 15 kΩ
Co mmon mode Input voltage range
VDD = 2.5V to 5.5V and CMRR ≥ 49dB VIC 0 VDD - 1.0 V
Test Set up
+
-
+
-
VDD
Audio Precision
Output Audio Precision
Input
30kHz low pass
RC filter
NAU82011 Z
L
0.1uF
0.1uF
Note: The 30kHz low pass RC fil te r is implemented by using R= 1k Ohm and C = 4.7nF
NAU82011WG Datasheet Rev1.0 Page 6 of 16 Dec, 2012
5 Typ ica l Ope rat ing Ch ara cte r is tic s
Conditions: EN = V DD = 5V, VSS = 0V, Av = 6dB (R1=150kΩ), ZL = ∞, unless otherwise specified, Ba ndwidth = 20Hz
to 22 kHz, TA = 25 oC, unless ot herwise no t ed
0.0001
0.001
0.01
0.1
1
20 200 2000 20000
THD+N (%)
Frequency (Hz)
THD+N vs Frequency
Pout 50mW
Pout 250mW
Pout 1W
ZL= 8Ω + 68μH
VDD 5V
0.0001
0.001
0.01
0.1
1
20 200 2000 20000
THD+N (%)
Frequency (Hz)
THD+N vs Frequency
Pout 25mW
Pout 125mW
Pout 500mW
ZL= 8Ω + 68μH
VDD 3.6V
0.0001
0.001
0.01
0.1
1
20 200 2000 20000
THD+N(%)
Frequency( HZ)
THD+N vs Frequency
Pout 15mW
Pout 75mW
Pout 200mW
ZL= 8Ω + 68μH
VDD 2.5V
0.0001
0.001
0.01
0.1
1
20 200 2000 20000
THD+N (%)
Frequency (Hz)
THD+N vs Frequency
Pout 100mW
Pout 500mW
Pout 2W
ZL= 4Ω +33μH
VDD 5V
NAU82011WG Datasheet Rev1.0 Page 7 of 16 Dec, 2012
0.0001
0.001
0.01
0.1
1
20 200 2000 20000
THD+N (%)
Frequency (Hz)
THD+N vs Frequency
Pout 50mW
Pout 250mW
Pout 1W
ZL= 4Ω + 33μH
VDD 3.6V
0.001
0.01
0.1
1
20 200 2000 20000
THD+N (%)
Frequency (Hz)
THD+N vs Frequency
Pout 30mW
Pout 150mW
Pout 400mW
ZL = 4Ω +33 μH
VDD 2.5V
0.001
0.01
0.1
1
10
100
0.01 0.1 110
THD+N [%]
Output Power [W]
THD+N vs Output Power
VDD 2.5V
VDD 3.6V
VDD 5V
ZL= 8Ω + 68μH
0.001
0.01
0.1
1
10
100
0.01 0.1 110
THD+N [%]
Output Power [W]
THD+N vs Output Power
VDD 2.5V
VDD 3.6V
VDD 5V
ZL= 4Ω+ 33μH
NAU82011WG Datasheet Rev1.0 Page 8 of 16 Dec, 2012
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.00 0.50 1.00 1.50 2.00
Supply Current [A]
Output Power [W]
Supply Current vs Output Power
Vdd 5V
Vdd 3.6V
Vdd 2.5V
ZL=8Ω + 68μH
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
01234
Supply Current [A]
Output Power [W]
Supply Current vs Output Power
VDD 5V
VDD 3.6V
VDD 2.5V
ZL=4Ω + 33μH
0
10
20
30
40
50
60
70
80
90
100
0.00 0.50 1.00 1.50 2.00
Efficiency [%]
Output Power [W]
Efficiency vs Output Power
VDD 5V
VDD 3.6V
VDD 2.5V
ZL=8Ω + 68μH
0
10
20
30
40
50
60
70
80
90
100
01234
Efficiency [%]
Output Power [W]
Efficiency vs Output Power
VDD 5V
VDD 3.6V
VDD 2.5V
ZL=4Ω + 33μH
NAU82011WG Datasheet Rev1.0 Page 9 of 16 Dec, 2012
Note1: All the above plots are captured with 0.1uF input capacitor. It is re c ommended to use 2.2uF input
capacitor to get a flat low frequency response.
Note2 : The above PSRR plots are c aptured with input c apacitors 2.2 uF
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
20 200 2000 20000
PSRR [dB]
Frequency [Hz]
PSRR vs Frequency
VDD 5V
VDD 3.6V
VDD 2.5V
ZL= 8Ω + 68μH
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
20 200 2000 20000
PSRR [dB]
Frequency [Hz]
PSRR vs Frequency
VDD 5V
VDD 3.6V
VDD 2.5V
ZL = 4Ω + 33μH
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
20 200 2000 20000
CMRR [dB]
Frequency [Hz]
CMRR vs Frequency
VDD 2.5V
VDD 3.6V
VDD 5V
ZL=8Ω+68µH
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
20 200 2000 20000
CMRR [dB]
Frequency [Hz]
CMRR vs Frequency
VDD 2.5V
VDD 3.6V
VDD 5V
ZL=4Ω+33µH
NAU82011WG Datasheet Rev1.0 Page 10 of 16 Dec, 2012
6 Special Feature Des c ription
The NAU82011WG offers excelle nt quantity performa nce as high efficiency, high ou tput power and low quiescent
current. It also provides the following special features.
6.1 Device Prote ct io n
The NAU82011WG includes device protection for three operating scenarios. They are
1. Thermal Overload
2. Short circuit
3. Supply und er vo lta ge
6.1.1 Thermal Overload Protection
When the device internal junction temperature reaches 150°C, the NAU82011WG will disable the output drivers. W hen
the device cools down and a safe operating temperature of 130°C has been reached for at least about 100ms, the output
drivers will be enabled again.
6.1.2 Short Circuit Protection
If a short circuit is detected on any of the pull-up or pull-down devices on the output drivers for at least 16.7µs, the
output drivers will be disabled for 100ms. The output drivers will then be enabled again and check for the short circuit. If
the short circ uit is still present, the output drivers are d isabled after 1 6.7µs. This cycle will continue until the short cir c uit
is removed. The short circuit t hre shold is 2.0A at 3.6V.
6.1.3 Supply under Voltage Protection
If the supply voltage drops under 2.1V, the output drivers will be disabled while the NAU82011WG control circuitry
still operates. This will avoid the battery supply to drag down too low before the host processor can safely shut down the
devices on the system. If the supply drops further below 1.6 V the internal power on reset is activated and puts the entire
device in power down state.
6.2 Power up and Power down Control
When the supply voltage ramps up, the internal power o n re set circuit get s tr iggered. At this time all inter nal c ir c uits will
be set to power down state. The d evice can be enabled by setting the EN p in high. Upon settin g t he EN pin hig h, the
device will go through an internal power up sequence in order to minimize ‘pops’ on the speaker output. The complete
power up sequence will take about 4ms. The device will power down in about 30µs, when t he EN pin is set l ow.
It is important to keep the input signal at zero amplitude in order to minimize the ‘pops’ when the EN pin is toggled.
NAU82011WG Datasheet Rev1.0 Page 11 of 16 Dec, 2012
7 Applicat ion Information
7.1 Application diagram
7.1.1 Single ended input configuration
VDD
VSS
Current / Thermal
Protection
VIN Class D
Modulator Output
Driver
VIP
NAU82011WG
EN
Click / Pop
Suppression
150 kΩ
150 kΩ
0.1µF
0.1µF
VDD
0.1µF 10µF
7.1.2 Differential input configuration
VDD
VSS
Current / Thermal
Protection
VIN Class D
Modulator Output
Driver
VIP
NAU82011WG
EN
Click / Pop
Suppression
150 kΩ
150 kΩ
0.1µF
0.1µF
VDD
0.1µF 10µF
NAU82011WG Datasheet Rev1.0 Page 12 of 16 Dec, 2012
7.2 Component selection
7.2.1 Input resistors for Gain
NAU82011WG has a provi sio n for va riable gain setting by using external input resisto rs. T he gain is expr essed as the
ratio of the internal feedback resistor of 300kΩ and the external input resistor R. The Gain is expressed as
 = 
  󰇡
󰇢  ()= 20 log  
 
7.2.2 Coupling Capacitors
An ac coupling capacitor (Cin) is used to bloc k the dc content from the input source. T he input resistance of the amplifier
(R) t ogether with the Cin will act as a high pass fi lte r. So depending on the requi red cut off frequency the Cin can be
calculated by using the following fo rmula
 = 1/21 Where  is the desired cut off frequency of the High pass filter.
Input
Output
Cin R1
Amplifier
7.2.3 Bypass Capacitors
Bypass capacitors are required to remove the ac ripple on the VDD pins. The value of these capacitors depends on the
length of the VDD trace. In most cases, 10uF and 0.1uF are enough to get the good p erformance.
7.3 Layout considerations
Good PCB layout and grounding techniques are essential to get the good audio performance. It is better to use low
resistance traces as these devices are driving low impedance loads. The resistance of the traces has a significant effect on
the output power delivered to the load. In order to dissipate more heat, use wide traces for the power and ground lines.
NAU82011WG Datasheet Rev1.0 Page 13 of 16 Dec, 2012
7.4 Class D without filter
The NAU82011WG is designed for use without any filter on the ou tput line. That means the outputs can be dire c tly
connected to the spe aker in the simplest co nfiguration. This type of filter le ss d e sign is suitable for po rtable applica tions
where the speaker is very close to the amplifier. In other words, this is pre fer a ble in applications wher e the length of the
traces between the speaker and amplifier is short. The following diagram shows this simp le configuration.
VOUTP
VOUTN
NAU82011WG outputs connected to speaker without filter circuit
7.5 Class D with filter
In some applications, the shorter trace lengths are not possible because of speaker size limitations and other layout
reasons. In these applications, the long traces will cause EMI issues. There are two types of filter circuits available to
reduce the EMI effects. These are ferrite bead and LC filters.
7.5.1 Ferrite Bead filter
The ferrite bead filters are used to red uce the high frequency emissions. The typical circuit diagram is shown in the
figure.
1nF
1 nF
Ferrite Bead
Ferrite Bead
VOUTP
VOUTN
NAU82011WG outputs connected to speaker with Ferrite Bead filter
The characteristic of ferrite bead is such that it offers higher impedance at high frequencies. For better EMI performance
select ferrite bead which o ffers highest impedance at high fr e quencies, so that it will attenuate the signals at higher
frequencies. Usually the ferrite beads have low impedance in the audio range, so it will act as a pass through filter in the
audio fre quency ra nge.
NAU82011WG Datasheet Rev1.0 Page 14 of 16 Dec, 2012
7.5.2 LC filter
The LC filter is used t o suppre s s the l ow frequency emissions. T he foll owing diagram shows the NAU82011WG outputs
connected to the spe aker with LC filter circuit. RL is the resistance of the speaker coil.
VOUTP
VOUTN L
C
C
RL
L
NAU82011WG outputs connected to speaker with LC filter
L
C
Input Output
R
Standar d Low pa ss LCR filte r
The following are the equations for the critically damped (ζ = 0.707) standard low pass LCR filter
2 =
()  is the cutoff frequenc y
= 0.707 =1
2
The L and C values for differential configuration can be calculated by duplicating the single ended configuration values
and subst ituting RL = 2R.
NAU82011WG Datasheet Rev1.0 Page 15 of 16 Dec, 2012
8 Package Dimensions
8.1 8 pin MSOP package
NAU82011WG Datasheet Rev1.0 Page 16 of 16 Dec, 2012
9 Ordering Information
Nuvoton Part Number Description
Version History
VERSION DATE PAGE DESCRIPTION
NAU82011WG
Datasheet Rev1.0 Dec, 2012 NA Revision1.0
Table 1: Version History
Important Notice
Nuvoton Products are neither intended nor warranted for usage in systems or equipment, any
malfunctio n o r failure of which may cause loss of human life, bod ily injury or severe pro p er ty damage.
Such applications are deemed, “Insecure Usage”.
Insecure usage includes, but is not limited to: equipment for surgical implementation, atomic energy
control instruments, airplane or spaceship instruments, the control or operation of dynamic, brake or
safety systems designed for vehicular use, traffic signal instrum ents, all types of safety devices , and
other applications inten ded to support or sustain life.
All Insecure Usage shall be made at customer’s risk, and in the event that third parties lay claims to
Nuvoton as a result of customer’s Insecure Usage, customer shall indemnify the damages and
liabilities thus incurred by Nuvoton.
Package Type:
W = 8-pin MSOP Package
NAU82011WG
Package Material:
G = Green Package