LM4990 Boomer ® Audio Power Amplifier Series 2 Watt Audio Power Amplifier with Selectable Shutdown Logic Level
LM4990
2 Watt Audio Power Amplifier with Selectable Shutdown
Logic Level
General Description
The LM4990 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 1.25 watts of continuous average power to an 8
BTL load and 2 watts of continuous average power (LD and
MH only) to a 4
BTL load with less than 1% distortion
(THD+N) from a 5V
DC
power supply.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4990 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for mobile phone and other low voltage appli-
cations where minimal power consumption is a primary re-
quirement.
The LM4990 features a low-power consumption shutdown
mode. To facilitate this, Shutdown may be enabled by either
logic high or low depending on mode selection. Driving the
shutdown mode pin either high or low enables the shutdown
pin to be driven in a likewise manner to enable shutdown.
The LM4990 contains advanced pop & click circuitry which
eliminates noise which would otherwise occur during turn-on
and turn-off transitions.
The LM4990 is unity-gain stable and can be configured by
external gain-setting resistors.
Key Specifications
j
Improved PSRR at 217Hz & 1KHz
62dB
j
Power Output at 5.0V, 1% THD,
4
(LD and MH only)
2W (typ)
j
Power Output at 5.0V, 1% THD, 8
1.25W (typ)
j
Power Output at 3.0V, 1% THD, 4
600mW (typ)
j
Power Output at 3.0V, 1% THD, 8
425mW (typ)
j
Shutdown Current
0.1A (typ)
Features
n
Available in space-saving packages: LLP, Exposed-DAP
TSSOP, and MSOP
n
Ultra low current shutdown mode
n
Improved pop & click circuitry eliminates noise during
turn-on and turn-off transitions
n
2.2 - 5.5V operation
n
No output coupling capacitors, snubber networks or
bootstrap capacitors required
n
Unity-gain stable
n
External gain configuration capability
n
User selectable shutdown High or Low logic Level
Applications
n
Mobile Phones
n
PDAs
n
Portable electronic devices
Connection Diagrams
Mini Small Outline (MSOP) Package
LLP Package
200510B9
Top View
Order Number LM4990MM
See NS Package Number MUA08A
200510B3
Top View
Order Number LM4990LD
See NS Package Number LDA10B
Boomer
is a registered trademark of National Semiconductor Corporation.
January 2003
LM4990
2
W
att
Audio
Power
Amplifier
with
Selectable
Shutdown
Logic
Level
2003 National Semiconductor Corporation
DS200510
www.national.com
Connection Diagrams
(Continued)
MSOP Marking
LLP Marking
20051071
Top View
Z - Plant Code
X - Date Code
TT - Die Traceability
G - Boomer Family
A5 - LM4990MM
200510B4
Top View
Z - Plant Code
XY - Date Code
TT - Die Traceability
Bottom Line - Part Number
Exposed-DAP TSSOP Package
20051096
Top View
Order Number LM4990MH
See NS Package Number MXF10A
Typical Application
20051001
FIGURE 1. Typical Audio Amplifier Application Circuit (LD and MH)
LM4990
www.national.com
2
Absolute Maximum Ratings
(Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (Note 11)
6.0V
Storage Temperature
-65C to +150C
Input Voltage
-0.3V to V
DD
+0.3V
Power Dissipation (Notes 3, 12)
Internally Limited
ESD Susceptibility (Note 4)
2000V
ESD Susceptibility (Note 5)
200V
Junction Temperature
150C
Thermal Resistance
JC
(MSOP)
56C/W
JA
(MSOP)
190C/W
JA
(LLP)
63C/W (Note 13)
JC
(LLP)
12C/W (Note 13)
Soldering Information
See AN-1187 "Leadless
Leadframe Package (LLP)."
Operating Ratings
Temperature Range
T
MIN
T
A
T
MAX
-40C
T
A
85C
Supply Voltage
2.2V
V
DD
5.5V
Electrical Characteristics V
DD
= 5V
(Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4990
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 9)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
o
= 0A, No Load
3
7
mA (max)
V
IN
= 0V, I
o
= 0A, 8
Load
4
10
mA (max)
I
SD
Shutdown Current
V
SD
= V
SD Mode
(Note 8)
0.1
2.0
A (max)
V
SDIH
Shutdown Voltage Input High
V
SD MODE
= V
DD
1.5
V
V
SDIL
Shutdown Voltage Input Low
V
SD MODE
= V
DD
1.3
V
V
SDIH
Shutdown Voltage Input High
V
SD MODE
= GND
1.5
V
V
SDIL
Shutdown Voltage Input Low
V
SD MODE
= GND
1.3
V
V
OS
Output Offset Voltage
7
50
mV (max)
R
OUT
Resistor Output to GND (Note 10)
8.5
9.7
k
(max)
7.0
k
(min)
P
o
Output Power (8
)
THD = 1% (max); f = 1kHz
1.25
0.9
W (min)
(4
) (Notes 13, 14)
THD = 1% (max); f = 1kHz
2
W
T
WU
Wake-up time
100
mS
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.5Wrms; f = 1kHz
0.2
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mV sine p-p
Input terminated with 10
60 (f =
217Hz)
64 (f = 1kHz)
55
dB (min)
Electrical Characteristics V
DD
= 3V
(Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4990
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 9)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
o
= 0A, No Load
2
7
mA (max)
V
IN
= 0V, I
o
= 0A, 8
Load
3
9
mA (max)
I
SD
Shutdown Current
V
SD
= V
SD Mode
(Note 8)
0.1
2.0
A (max)
V
SDIH
Shutdown Voltage Input High
V
SD MODE
= V
DD
1.1
V
V
SDIL
Shutdown Voltage Input Low
V
SD MODE
= V
DD
0.9
V
V
SDIH
Shutdown Voltage Input High
V
SD MODE
= GND
1.3
V
V
SDIL
Shutdown Voltage Input Low
V
SD MODE
= GND
1.0
V
V
OS
Output Offset Voltage
7
50
mV (max)
R
OUT
Resistor Output to GND (Note 10)
8.5
9.7
k
(max)
7.0
k
(min)
LM4990
www.national.com
3
Electrical Characteristics V
DD
= 3V
(Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
=
25C. (Continued)
Symbol
Parameter
Conditions
LM4990
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 9)
P
o
Output Power (8
)
THD = 1% (max); f = 1kHz
425
mW
(4
)
THD = 1% (max); f = 1kHz
600
mW
T
WU
Wake-up time
75
mS
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.25Wrms; f = 1kHz
0.1
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mV sine p-p
Input terminated with 10
62 (f =
217Hz)
68 (f = 1kHz)
55
dB (min)
Electrical Characteristics V
DD
= 2.6V
(Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4990
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 9)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
o
= 0A, No Load
2.0
mA
V
IN
= 0V, I
o
= 0A, 8
Load
3.0
mA
I
SD
Shutdown Current
V
SD
= V
SD Mode
(Note 8)
0.1
A
V
SDIH
Shutdown Voltage Input High
V
SD MODE
= V
DD
1.0
V
V
SDIL
Shutdown Voltage Input Low
V
SD MODE
= V
DD
0.9
V
V
SDIH
Shutdown Voltage Input High
V
SD MODE
= GND
1.2
V
V
SDIL
Shutdown Voltage Input Low
V
SD MODE
= GND
1.0
V
V
OS
Output Offset Voltage
5
50
mV (max)
R
OUT
Resistor Output to GND (Note 10)
8.5
9.7
k
(max)
7.0
k
(min)
P
o
Output Power ( 8
)
THD = 1% (max); f = 1kHz
300
mW
( 4
)
THD = 1% (max); f = 1kHz
400
T
WU
Wake-up time
70
mS
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.15Wrms; f = 1kHz
0.1
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mV sine p-p
Input terminated with 10
51 (f =
217Hz)
51 (f = 1kHz)
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
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 LM4990, see power derating
curves for additional information.
Note 4: Human body model, 100 pF discharged through a 1.5 k
resistor.
Note 5: Machine Model, 220 pF240 pF discharged through all pins.
Note 6: Typicals are measured at 25C and represent the parametric norm.
Note 7: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 8: For micro SMD only, shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase I
SD
by a maximum of 2A.
Note 9: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 10: R
ROUT
is measured from the output pin to ground. This value represents the parallel combination of the 10k
output resistors and the two 20k resistors.
Note 11: If the product is in Shutdown mode and V
DD
exceeds 6V (to a max of 8V V
DD
), then most of the excess current will flow through the ESD protection circuits.
If the source impedance limits the current to a max of 10mA, then the device will be protected. If the device is enabled when V
DD
is greater than 5.5V and less than
6.5V, no damage will occur, although operation life will be reduced. Operation above 6.5V with no current limit will result in permanent damage.
Note 12: Maximum power dissipation in the device (P
DMAX
) occurs at an output power level significantly below full output power. P
DMAX
can be calculated using
Equation 1 shown in the Application Information section. It may also be obtained from the power dissipation graphs.
LM4990
www.national.com
4
Electrical Characteristics V
DD
= 2.6V
(Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
A
=
25C. (Continued)
Note 13: The Exposed-DAP of the LDA10B package should be electrically connected to GND or an electrically isolated copper area. the LM4990LD demo board
has the Exposed-DAP connected to GND with a PCB area of 86.7mils x 585mils (2.02mm x 14.86mm) on the copper top layer and 550mils x 710mils (13.97mm
x 18.03mm) on the copper bottom layer.
Note 14: The thermal performance of the LLP and exposed-DAP TSSOP packages when used with the exposed-DAP connected to a thermal plane is sufficient for
driving 4
loads. The MSOP package does not have the thermal performance necessary for driving 4 loads with a 5V supply and is not recommended for this
application.
External Components Description
See (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
.
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
.
Typical Performance Characteristics
LD and MH Specific Characteristics
THD+N vs Frequency
V
DD
= 5V, R
L
= 4
, and P
O
= 1W
THD+N vs Output Power
V
DD
= 5V, R
L
= 4
, and f = 1 kHz
20051030
20051031
LM4990
www.national.com
5
Document Outline
PDF 
ZIP