LM4954
High Voltage 3 Watt Audio Power Amplifier
General Description
The LM4954 is an audio power amplifier primarily designed
for demanding applications in mobile phones and other por-
table communication device applications. It is capable of
delivering 2.4 Watts of continuous average power to an 8
BTL load with less than 1% THD+N from a 7V
DC
power
supply.
Boomer audio power amplifiers are designed specifically to
provide high quality output power with a minimal number of
external components. The LM4954 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for lower-power portable applications where
minimal space and power consumption are primary require-
ments.
The LM4954 features a low-power consumption global shut-
down mode which is achieved by driving the shutdown pin
with logic low. Additionally, the LM4954 features an internal
thermal shutdown protection mechanism.
The LM4954 contains advanced pop & click circuitry which
eliminates noises that would otherwise occur during turn-on
and turn-off transitions.
The LM4954 is unity-gain stable and can be configured by
external gain-setting resistors.
Key Specifications
j
Wide Power Supply
Voltage Range
2.7
V
DD
9V
j
Output Power: V
DD
= 7V, 1% THD+N
2.4W (typ)
j
Quiescent power supply current
3mA (typ)
j
PSRR: V
DD
= 5V and 3V at 217Hz
80dB (typ)
j
Shutdown power supply current
0.01A (typ)
Features
n
No output coupling capacitors, snubber networks or
bootstrap capacitors required
n
Unity gain stable
n
Externally configurable gain
n
Ultra low current active low shutdown mode
n
BTL output can drive capacitive loads up to 100pF
n
"Click and pop" suppression circuitry
n
2.7V - 9.0V operation
n
Available in space-saving microSMD package
Applications
n
Mobile Phones
n
PDAs
Typical Application
Boomer
is a registered trademark of National Semiconductor Corporation.
20129111
FIGURE 1. Typical Audio Amplifier Application Circuit
June 2005
LM4954
High
V
oltage
3
W
att
Audio
Power
Amplifier
2005 National Semiconductor Corporation
DS201291
www.national.com
Connection Diagrams
9 Bump micro SMD
9 Bump micro SMD Marking
20129186
Top View
Order Number LM4954TL, LM4954TLX
See NS package Number TLA0911A
20129191
Top View
X - Date Code
T - Die Traceability
G - Boomer Family
F2 - LM4954TL
LM4954
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2
Absolute Maximum Ratings
(Notes 1, 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (Note 1)
9.5V
Storage Temperature
-65C to +150C
Input Voltage
-0.3V to V
DD
+0.3V
Power Dissipation (Note 3)
Internally Limited
ESD Susceptibility (Note 4)
2000V
ESD Susceptibility (Note 5)
200V
Junction Temperature
150C
Thermal Resistance
JA
(microSMD) (Note 10)
180C/W
Soldering Information
See AN-112 "microSMD Wafers
Level Chip Scale Package."
Operating Ratings
(Notes 1, 2)
Temperature Range
T
MIN
T
A
T
MAX
-40C
T
A
85C
Supply Voltage
2.7V
V
DD
9V
Electrical Characteristics V
DD
= 7V
(Notes 1, 2)
The following specifications apply for V
DD
= 7V, A
V-BTL
= 6dB, and R
L
= 8
unless otherwise specified. Limits apply for T
A
=
25C.
Symbol
Parameter
Conditions
LM4954
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 8)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, R
L
= 8
BTL
3
5
mA (max)
I
SD
Shutdown Current
V
SD
= GND (Note 9)
0.01
1
A (max)
V
OS
Output Offset Voltage
10
25
mV (max)
P
o
Output Power (Note 11)
THD+N = 1% (max); f = 1kHz
2.4
2.2
W (min)
THD+N = 10% (max); f = 1kHz
3.0
W
THD+N
Total Harmonic Distortion + Noise
P
O
= 1Wrms; f = 1kHz
A
V-BTL
= 6dB
0.1
%
P
O
= 1Wrms; f = 1kHz
A
V-BTL
= 26dB
0.4
%
PSRR
Power Supply Rejection Ratio
V
Ripple
= 200mVsine p-p,
C
B
= 2.2F, Input terminated
with 10
to GND
f
Ripple
= 217Hz, Input Referred
71
54
dB (min)
V
Ripple
= 200mVsine p-p,
C
B
= 2.2F, Input terminated
with 10
to ground
f
Ripple
= 1kHz, Input Referred
71
55
dB (min)
V
SDIH
Shutdown High Input Voltage
1.2
V (min)
V
SDIL
Shutdown Low Input Voltage
0.4
V (max)
T
WU
Wake-up Time
C
B
= 2.2F
130
ms
OUT
Output Noise
A-Wtg, A
V-BTL
= 6dB
Input terminated with 10
to GND,
Output Referred
20
V
RMS
A-Wtg, A
V-BTL
= 26dB
Input terminated with 10
to GND,
Output Referred
100
V
RMS
R
PD
Pull Down Resistor on Shutdown
75
k
LM4954
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3
Electrical Characteristics V
DD
= 5V
(Notes 1, 2)
The following specifications apply for V
DD
= 5V, A
V-BTL
= 6dB, and R
L
= 8
unless otherwise specified. Limits apply for T
A
=
25C.
Symbol
Parameter
Conditions
LM4954
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 8)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, R
L
= 8
BTL
2.7
5
mA (max)
I
SD
Shutdown Current
V
SD
= GND (Note 9)
0.01
1
A (max)
V
OS
Output Offset Voltage
8
25
mV (max)
P
o
Output Power
THD+N = 1% (max); f = 1kHz
1.2
1.1
W (min)
THD+N
Total Harmonic Distortion + Noise
P
O
= 600mWrms; f = 1kHz
0.1
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mVsine p-p,
C
B
= 2.2F, Input terminated
with 10
to GND
f
Ripple
= 217Hz, Input Referred
80
63
dB (min)
V
ripple
= 200mVsine p-p,
C
B
= 2.2F, Input terminated
with 10
to GND
f
Ripple
= 1kHz, Input Referred
80
dB
V
SDIH
Shutdown High Input Voltage
1.2
V (min)
V
SDIL
Shutdown Low Input Voltage
0.4
V (max)
T
WU
Wake-up Time
C
B
= 2.2F
130
ms
OUT
Output Noise
A-Wtg, Input terminated with 10
to GND,
Output referred
20
V
RMS
R
PD
Pul Down Resistor on Shutdown
75
k
Electrical Characteristics V
DD
= 3V
(Notes 1, 2)
The following specifications apply for V
DD
= 3V, A
V-BTL
= 6dB, and R
L
= 8
unless otherwise specified. Limits apply for T
A
=
25C.
Symbol
Parameter
Conditions
LM4954
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 8)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, R
L
= 8
BTL
2.5
5
mA (max)
I
SD
Shutdown Current
V
SD
= GND (Note 9)
0.01
1
A (max)
V
OS
Output Offset Voltage
5
25
mV (max)
P
o
Output Power
THD+N = 1% (max); f = 1kHz
380
360
mW (min)
THD+N
Total Harmonic Distortion + Noise
P
o
= 100mWrms; f = 1kHz
0.18
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mVsine p-p,
C
B
= 2.2F, Input teiminated
with 10
to GND,
f
Ripple
= 217Hz, Input referred
80
63
dB (min)
V
ripple
= 200mVsine p-p,
C
B
= 2.2F, Input teiminated
with 10
to GND,
f
Ripple
= 1kHz, Input referred
80
dB
V
SDIH
Shutdown High Input Voltage
1.2
V (min)
V
SDIL
Shutdown Low Input Voltage
0.4
V (max)
T
WU
Wake-Up Time
C
B
= 2.2F
130
ms
OUT
Output Noise
A-Wtg, Input terminated with 10
to GND,
Output referred
20
V
RMS
R
PD
Pull Down Resistor on Shutdown
75
k
LM4954
www.national.com
4
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
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 3: 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 LM4954, see power
derating curves for additional information.
Note 4: Human body model, 100pF discharged through a 1.5k
resistor.
Note 5: Machine Model, 220pF 240pF discharged through all pins.
Note 6: Typical specifications are specified at 25C and represent the parametric norm.
Note 7: Tested limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 8: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 9: Shutdown current is measured in a normal room environment. Exposure to direct sunlight in the TL package will increase I
SD
by a minimum of 2A.
Note 10: All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The
JA
in the Thermal Resistance section
is for the ITL package without any heat spreading planes on the PCB.
Note 11: The demo board shown has 1.1in
2
(710mm
2
) heat spreading planes on the two internal layers and the bottom layer. The bottom internal layer is electrically
V
DD
while the top internal and bottom layers are electrically GND. Thermal performance for the demo board is found on the Power Derating graph in the Typical
Performance Characteristics section. 7V operation requires heat spreading planes for the thermal stability.
External Components Description
(Figure 1)
Components
Functional Description
1.
R
i
Inverting input resistance which sets the closed-loop gain in conjunction with R
f
. This resistor also forms a
high pass filter with C
i
at f
C
= 1/(2
R
i
C
i
).
2.
C
i
Input coupling capacitor which blocks the DC voltage at the amplifiers input terminals. Also creates a
highpass filter with R
i
at f
c
= 1/(2
R
i
C
i
). Refer to the section, Proper Selection of External Components,
for an explanation of how to determine the value of C
i
.
3.
R
f
Feedback resistance which sets the closed-loop gain in conjunction with R
i
. A
VD
= 2 * (R
f
/R
i
).
4.
C
S
Supply bypass capacitor which provides power supply filtering. Refer to the Power Supply Bypassing
section for information concerning proper placement and selection of the supply bypass capacitor.
5.
C
B
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 C
B
.
LM4954
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