NSC LM4818M Datasheet
LM4818
350mW Audio Power Amplifier with Shutdown Mode
LM4818 350mW Audio Power Amplifier with Shutdown Mode
April 2002
General Description
The LM4818 is a mono bridged power amplifier that is capable of delivering 350mW
or 300mW
THD+N from a 5V power supply.
The LM4818 Boomer audio power amplifier is designed
specifically to provide high quality output power and minimize PCB area with surface mount packaging and a minimal
amount of external components. Since the LM4818 doesnot
require output coupling capacitors, bootstrap capacitors or
snubber networks, it is optimally suited for low-power portable applications.
The closed loop response of the unity-gain stable LM4818
can be configured using external gain-setting resistors. The
device is available in SO package type to suit various applications.
output power into an 8Ω load with 10%
RMS
output power into a 16Ω load
RMS
Typical Application
Key Specifications
n THD+N at 1kHz, 350mW continuous average output
power into 16Ω 10% (max)
n THD+N at 1kHz, 300mW continuous average output
power into 8Ω 10% (max)
n Shutdown Current 0.7µA (typ)
Features
n SOP surface mount packaging.
n Switch on/off click suppression.
n Unity-gain stable.
n Minimum external components.
Applications
n General purpose audio
n Portable electronic devices
n Information Appliances (IA)
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FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer®is a registered trademark of National Semiconductor Corporation.
© 2002 National Semiconductor Corporation DS200389 www.national.com
Connection Diagrams
LM4818
Small Outline (SO) Package
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Top View
Order Number LM4818M
See NS Package Number M08A
SO Marking
DS200389-72
Top View
XY - Date Code
TT - Die Traceability
Bottom 2 lines - Part Number
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LM4818
Absolute Maximum Ratings (Notes 2, 3)
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 −65˚C to +150˚C
Input Voltage −0.3V to V
Power Dissipation (P
) (Note 4) Internally Limited
D
DD
+0.3V
Operating Ratings (Notes 2, 3)
ESD Susceptibility (Note 5) 2.5kV
ESD Susceptibility (Note 6) 200V
Junction Temperature (T
) 150˚C
J
Soldering Information (Note 1)
Electrical Characteristics VDD=5V(Notes 2, 3)
The following specifications apply for V
Symbol Parameter Conditions
I
DD
I
SD
I
SDIH
I
SDIL
V
P
OS
O
Quiescent Power Supply Current VIN= 0V, Io= 0A 1.5 3.0 mA (max)
Shutdown Current V
Shutdown Voltage Input High 4.0 V (min)
Shutdown Voltage Input Low 1.0 V (max)
Output Offset Voltage VIN= 0V 5 50 mV (max)
Output Power
THD+N Total Harmonic Distortion + Noise P
= 5V, RL=16Ωunless otherwise stated. Limits apply for TA= 25˚C.
DD
PIN1=VDD
THD = 10%, f
THD = 10%, f
= 270mW
O
(Note 10) 1.0 5.0 µA (max)
= 1kHz 350 mW
IN
= 1kHz, RL=8Ω 300 mW
IN
RMS,AVD
1kHz
Small Outline Package
Vapor Phase (60 seconds) 215˚C
Infrared (15 seconds) 220˚C
Thermal Resistance
θ
(SOP) 35˚C/W
JC
θ
(SOP) 170˚C/W
JA
Temperature Range
T
MIN
≤ TA≤ T
MAX
−40˚C ≤ TA≤ 85˚C
Supply Voltage 2.0V ≤ V
LM4818
Typical Limit
(Note 7) (Notes 8, 9)
=2,fIN=
1%
≤ 5.5V
CC
Units
(Limits)
Electrical Characteristics VDD=3V(Notes 2, 3)
The following specifications apply for V
Symbol Parameter Conditions
I
DD
I
SD
I
SDIH
I
SDIL
V
P
OS
O
Quiescent Power Supply Current VIN= 0V, Io= 0A 1.0 3.0 mA (max)
Shutdown Current V
Shutdown Voltage Input High 2.4 V (min)
Shutdown Voltage Input Low 0.6 V (max)
Output Offset Voltage VIN= 0V 5 50 mV
Output Power
THD+N Total Harmonic Distortion + Noise P
= 3V and RL=16Ωload unless otherwise stated. Limits apply to TA= 25˚C.
DD
PIN1=VDD
THD = 10%, f
THD = 10%, f
= 80mW
O
(Note 10) 0.7 5.0 µA (max)
= 1kHz 110 mW
IN
= 1kHz, RL=8Ω 90 mW
IN
RMS,AVD
1kHz
=2,fIN=
LM4818
Typical Limit
(Note 7) (Notes 8, 9)
Units
(Limits)
1%
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Electrical Characteristics VDD=3V(Notes 2, 3)
The following specifications apply for V
LM4818
25˚C. (Continued)
Note 1: See AN-450 ’Surface Mounting and their Effects on Product Reliability’ for other methods of soldering surface mount devices.
Note 2: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 3:
Absolute Maximum Ratings
functional, but do not guarantee specific performance limits.
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’s performance.
Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
allowable power dissipation is P
mounted is 170˚C/W for the SOP package.
Note 5: Human body model, 100pF discharged through a 1.5 kΩ resistor.
Note 6: Machine Model, 220pF–240pF capacitor is discharged through all pins.
Note 7: Typical specifications are specified at 25˚C and represent the parametric norm.
Note 8: Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 9: Datasheet min/max specification limits are guaranteed by designs, test, or statistical analysis.
Note 10: The Shutdown pin (pin 1) should be driven as close as possible to V
indicate limits beyond which damage to the device may occur.
=(T
DMAX
JMAX–TA
= 3V and RL=16Ωload unless otherwise stated. Limits apply to TA=
DD
Electrical Characteristics
)/θJA. For the LM4818, T
state DC and AC electrical specifications under particular test conditions which
= 150˚C and the typical junction-to-ambient thermal resistance (θJA) when board
JMAX
for minimum current in Shutdown Mode.
DD
Operating Ratings
, θJA, and the ambient temperature TA. The maximum
JMAX
indicate conditions for which the device is
External Components Description (
Figure 1
)
Components Functional Description
1. R
2. C
3. R
4. C
Combined with Rf, this inverting input resistor sets the closed-loop gain. Rialso forms a high pass filter with
i
i
f
S
at fc= 1/(2πRiCi).
C
i
This input coupling capacitor blocks DC voltage at the amplifier’s terminals. Combined with Ri, it creates a
high pass filter with R
for an explanation of how to determine the value of C
at fc= 1/(2πRiCi). Refer to the section, Proper Selection of External Components
i
.
i
Combined with Ri, this is the feedback resistor that sets the closed-loop gain: Av= 2(RF/Ri).
This is the power supply bypass capacitor that filters the voltage applied to the power supply pin. Refer to
the Application Information section for proper placement and selection of C
5. C
This is the bypass pin capacitor that filters the voltage at the BYPASS pin. Refer to the section, Proper
B
Selection of External Components for information concerning proper placement and selection of C
6. C
This is an optional capacitor that is not needed in the majority of applications. If the capacitor is not used,
B2
pin 3 should be connected directly to pin2. Refer to the section Proper Selection of External Components
for more information concerning C
.
B2
Typical Performance Characteristics
.
s
.
B
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Typical Performance Characteristics (Continued)
LM4818
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DS200389-43 DS200389-44
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