LM4913
2W Monaural, 90mW Stereo Headphone Audio Amplifier
General Description
The unity-gain stable LM4913 is both a mono differential
output (for bridge-tied loads, or BTL) audio power amplifier
and a single-ended (SE) stereo headphone amplifier. Oper-
ating on a single 5V supply, the mono BTL mode delivers 2W
(typ) to a 4
load (Note 1) at 0.3% THD+N. In SE stereo
mode, the amplifier will deliver 90mW to 32
loads. The
LM4913 features circuitry that suppresses output transients
("clicks and pops").
The LM4913 is designed for notebook and other handheld
portable applications. It delivers high quality output power
from a surface-mount package and requires few external
components. The LM4913 is pin and functionally compatible
with the TPA0213.
Other features include an active-low micro-power shutdown
mode and thermal shutdown protection.
The LM4913 is available a space efficient 10-lead exposed-
DAP TSSOP package.
Note 1: When operating on a 5VDC supply, an LM4913MH that has been
properly mounted to a circuit board will deliver 2W into 4
. See the Applica-
tion Information sections for further information concerning PCB layout sug-
gestions to maximize the LM4913MH's output power with a 4
load.
Key Specifications
j
BTL output power (R
L
= 4
)
V
DD
= at 3.0V, THD = 1%
V
DD
= at 5.0V, THD = 0.3%
660mW (typ)
2W (typ)
j
SE output power (R
L
= 32
and THD = 0.1%)
V
DD
= at 3.0V
V
DD
= at 5.0V
33mW (typ)
90mW (typ)
j
Micro-power shutdown supply current
1A (typ)
j
PSRR (
@
1kHz, 2.9V
VDD
5.1V, (Fig. 1))
BTL
SE
52dB (typ)
62dB (typ)
Features
n
Advanced "click and pop" suppression circuitry
n
Stereo headphone amplifier mode
n
Low current micro-power shutdown mode
n
Thermal shutdown protection circuitry
n
2.5V to 5.5V operation
n
Unity-gain stable
n
Gain set with external resistors
n
Space-saving exposed-DAP TSSOP package
Applications
n
PDAs
n
Cellular phones
n
Handheld portable electronic devices
Connection Diagram
200617A0
Top View
Order Number LM4913MH
See NS package Number MXF10A
Boomer
is a registered trademark of National Semiconductor Corporation.
December 2002
LM4913
2W
Monaural,
90mW
Stereo
Headphone
Audio
Amplifier
2002 National Semiconductor Corporation
DS200617
www.national.com
Typical Application
20061799
FIGURE 1. Typical Audio Amplifier Application Circuit
LM4913
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2
Absolute Maximum Ratings
(Notes 3,
4)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
6.0V
Storage Temperature
-65C to +150C
Input Voltage
-0.3V to V
DD
+0.3V
Power Dissipation (Note 5)
Internally Limited
ESD Susceptibility (Note 6)
2000V
ESD Susceptibility (Note 7)
200V
Junction Temperature
150C
Solder Information
Small Outline Package
Vapor Phase (60sec)
215C
Infrared (15sec)
220C
Thermal Resistance
JA
(MXF10A)
46C/W (Note 8)
Operating Ratings
Temperature Range
T
MIN
T
A
T
MAX
-40C
T
A
85C
Supply Voltage
2.5V
V
DD
5.5V
Electrical Characteristics for Entire Amplifier (V
DD
= 5V)
(Notes 4, 9)
The following specifications apply for the circuit shown in Figure 1 unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4913
Units
(Limits)
Typical
Limit
(Note 9)
(Notes 10,
11)
V
DD
Supply Voltage
2.5
5.5
V (min)
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
O
= 0A, No Load
4
8
mA (max)
I
SD
Shutdown Quiescent Power Supply
Current
V
SHUTDOWN
= GND
1
6
A (max)
R
IN
Input Resistance
50
k
V
OS
Output Offset Voltage
5
30
mV (max)
PSRR
Power Supply Rejection Ratio
V
DD
= 3V, C
BYPASS
= 0.47F,
V
ripple
= 200mVp-p 1kHz sine wave
BTL, R
L
= 4
BTL, SE, R
L
= 32
58
60
dB
dB
HP-S
VIH
HP-SENSE Logic-High Threshold
Voltage
4.5
V (min)
HP-S
VIL
HP-SENSE Logic-Low Threshold
Voltage
2.75
V (max)
SD
VIH
Shutdown Logic High Threshold
2.0
V (min)
SD
VIL
Shutdown Logic LowThreshold
0.8
V (max)
LM4913
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3
Electrical Characteristics: Bridged-Mode Operation (V
DD
= 5V)
(Notes 4, 9)
The following specifications apply for the circuit shown in Figure 1, R
L
= 4
, and a measurement bandwidth of 20Hz to
80kHz, unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4913
Units
(Limits)
Typical
Limit
(Note 9)
(Notes 10,
11)
P
O
Output Power (Note 11)
THD = 0.3% (max); f = 1kHz
R
L
= 4
(Note 12)
2
W
THD+N
Total Harmonic Distortion + Noise
R
L
= 4
, P
O
= 1.5W, f = 1kHz
0.2
%
V
ON
Output Voltage Noise
C
B
= 0.47F, 20Hz
<
f
<
20kHz
21
V
RMS
Electrical Characteristics: SE Operation (V
DD
= 5V)
(Notes 4, 9)
The following specifications apply for the circuit shown in Figure 1, R
L
= 4
, and a measurement bandwidth of 20Hz to
80kHz, unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4913
Units
(Limits)
Typical
Limit
(Note 9)
(Notes 10,
11)
P
O
Output Power (Note 11)
THD+N = 0.1%, f = 1kHz, R
L
=
32
90
mW
THD+N
Total Harmonic Distortion + Noise
f = 1kHz
R
L
=32
, P
O
= 70mW
0.2
%
%
V
ON
Output Voltage Noise
C
B
= 0.47F, 20Hz
<
f
<
20kHz
12
V
RMS
Electrical Characteristics for Entire Amplifier (V
DD
= 3V)
(Notes 4, 9)
The following specifications apply for the circuit shown in Figure 1 unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4913
Units
(Limits)
Typical
Limit
(Note 9)
(Notes 10,
11)
V
DD
Supply Voltage
2.7
5.5
V (min)
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
O
= 0A, No Load
3
7
mA (max)
I
SD
Shutdown Quiescent Power Supply
Current
V
SHUTDOWN
= GND
1
4
A (max)
V
OS
Output Offset Voltage
7
30
mV (max)
PSRR
Power Supply Rejection Ratio
V
DD
= 3V, C
BYPASS
= 0.47F,
V
ripple
= 200mVp-p 1kHz sine wave
BTL, R
L
= 8
BTL, SE, R
L
= 32
58
60
dB
dB
HP-S
VIH
HP-SENSE Logic-High Threshold
Voltage
2.7
V (min)
HP-S
VIL
HP-SENSE Logic-Low Threshold
Voltage
1.65
V (max)
SD
VIH
Shutdown Logic High Threshold
2
V (min)
SD
VIL
Shutdown Logic LowThreshold
0.8
V (max)
LM4913
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4
Electrical Characteristics: Bridged-Mode Operation (V
DD
= 3V)
(Notes 4, 9)
The following specifications apply for the circuit shown in Figure 1, R
L
= 4
, and a measurement bandwidth of 20Hz to
80kHz, unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4913
Units
(Limits)
Typical
Limit
(Note 9)
(Notes 10,
11)
P
O
Output Power (Note 11)
THD = 1% (max); f = 1kHz (Note
12)
R
L
= 4
(THD = 0.1%)
660
W
THD+N
Total Harmonic Distortion + Noise
f = 1kHz
R
L
= 4
, P
O
= 500mW
0.2
%
V
ON
Output Voltage Noise
C
B
= 0.47F, 20Hz
<
f
<
20kHz
21
V
RMS
Electrical Characteristics: SE Operation (V
DD
= 3V)
(Notes 4, 9)
The following specifications apply for the circuit shown in Figure 1, R
L
= 4
, and a measurement bandwidth of 20Hz to
80kHz, unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4913
Units
(Limits)
Typical
Limit
(Note 9)
(Notes 10,
11)
P
O
Output Power (Note 11)
THD+N = 0.1%, f = 1kHz, R
L
=
32
33
30
mW
THD+N
Total Harmonic Distortion + Noise
f = 1kHz
R
L
=32
, P
O
= 30mW
0.1
%
V
ON
Output Voltage Noise
C
B
= 0.47F, 20Hz
<
f
<
20kHz
12
V
RMS
Note 2: An LM4913MH that has been properly mounted to a circuit board with a copper heatsink area of at least 2in
2
will deliver 2.1W into 4
.
Note 3: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 4: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which
guarantee 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 5: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
JMAX
,
JA
, and the ambient temperature T
A
. The maximum
allowable power dissipation is P
DMAX
= (T
JMAX
T
A
)/
JA
or the number given in Absolute Maximum Ratings, whichever is lower. For the LM4913, see power derating
curves for additional information.
Note 6: Human body model, 100pF discharged through a 1.5k
resistor.
Note 7: Machine Model, 220pF240pF discharged through all pins.
Note 8: The given
JA
is for an LM4913 packaged in an MXF10A with the Exposed-DAP soldered to an exposed 2in
2
area of 1oz printed circuit board copper.
Note 9: Typicals are measured at 25C and represent the parametric norm.
Note 10: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 11: Datasheet minimum and maximum specification limits are guaranteed by design, test, or statistical analysis.
Note 12: Output power is measured at the amplifier's package pins.
Note 13: When driving 4
loads and operating on a 5V supply, the LM4913MH must be mounted to a circuit board that has a minimum of 2.5in
2
of exposed,
uninterrupted copper area connected to the MH package's exposed DAP.
Note 14: See Application Information section "Single-Ended Output Power Performance and Measurement Considerations" for more information.
LM4913
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5
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