LM4877
1 Watt Audio Power Amplifier in micro SMD package
with Shutdown Logic Low
General Description
The LM4877 is a bridge-connected audio power amplifier ca-
pable of delivering 1 W of continuous average power to an
8
load with less than .2% (THD) from a 5V power supply.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. Since the LM4877 does not require
output coupling capacitors or bootstrap capacitors. It is opti-
mally suited for low-power portable applications.
The LM4877 features an externally controlled, low-power
consumption shutdown mode, as well as an internal thermal
shutdown protection mechanism.
The unity-gain stable LM4877 can be configured by external
gain-setting resistors.
Key Specifications
n
Power Output at 0.2% THD
1 W (typ)
n
Shutdown Current
0.01 A (typ)
Features
n
micro SMD package (see App. note AN-1112)
n
5V - 2V operation
n
No output coupling capacitors or bootstrap capacitors.
n
Unity-gain stable
n
External gain configuration capability
Applications
n
Cellular Phones
n
Portable Computers
n
Low Voltage Audio Systems
Typical Application
Connection Diagram
Boomer
is a registered trademark of National Semiconductor Corporation.
DS101290-1
FIGURE 1. Typical Audio Amplifier Application Circuit
8 Bump micro SMD
DS101290-23
Top View
Order Number LM4877IBP, LM4877IBPX
See NS Package Number BPA08B6B
February 2000
LM4877
1
W
att
Audio
Power
Amplifier
micro
SMD
package
with
Shutdown
Logic
Low
2000 National Semiconductor Corporation
DS101290
www.national.com
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
6.0V
Storage Temperature
-65C to +150C
Input Voltage
-0.3V to V
DD
+0.3V
Power Dissipation (Note 3)
Internally Limited
ESD Susceptibility (Note 4)
2500V
ESD Susceptibility (Note 5)
250V
Junction Temperature
150C
Soldering Information
See AN-1112
Micro-SMD Wafers Level Chip Scale
Package
.
Operating Ratings
Temperature Range
T
MIN
T
A
T
MAX
-40C
T
A
85C
Supply Voltage
2.0V
V
DD
5.5V
Electrical Characteristics V
DD
= 5V
(Notes 1, 2, 9)
The following specifications apply for V
DD
= 5V and 8
Load unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4877
Units
(Limits)
Typical
Limit
(Note 6)
(Note 7)
V
DD
Supply Voltage
2.0
V (min)
5.5
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
o
= 0A
5.3
7
mA (max)
I
SD
Shutdown Current
V
PIN5
= 0V
0.01
2
A (max)
V
OS
Output Offset Voltage
V
IN
= 0V
5
50
mV (max)
P
o
Output Power
THD = 0.2% (max); f = 1 kHz
1
W
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.25 Wrms; A
VD
= 2; 20 Hz
f
20 kHz
0.1
%
PSRR
Power Supply Rejection Ratio
V
DD
= 4.9V to 5.1V
65
dB
Electrical Characteristics V
DD
= 3.3V
(Notes 1, 2, 9)
The following specifications apply for V
DD
= 3.3V and 8
Load unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4877
Units
(Limits)
Typical
Limit
(Note 6)
(Note 7)
V
DD
Supply Voltage
2.0
V (min)
5.5
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
o
= 0A
4
mA (max)
I
SD
Shutdown Current
V
PIN5
= 0V
0.01
A (max)
V
OS
Output Offset Voltage
V
IN
= 0V
5
mV (max)
P
o
Output Power
THD = 1% (max); f = 1 kHz
.5
.45
W
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.25 Wrms; A
VD
= 2; 20 Hz
f
20 kHz
0.15
%
PSRR
Power Supply Rejection Ratio
V
DD
= 3.2V to 3.4V
65
dB
Electrical Characteristics V
DD
= 2.6V
(Notes 1, 2, 8, 9)
The following specifications apply for V
DD
= 2.6V and 8
Load unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4877
Units
(Limits)
Typical
Limit
(Note 6)
(Note 7)
V
DD
Supply Voltage
2.0
V (min)
5.5
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
o
= 0A
3.4
mA (max)
LM4877
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2
Electrical Characteristics V
DD
= 2.6V
(Notes 1, 2, 8, 9)
The following specifications apply for V
DD
= 2.6V and 8
Load unless otherwise specified. Limits apply for T
A
=
25C. (Continued)
Symbol
Parameter
Conditions
LM4877
Units
(Limits)
Typical
Limit
(Note 6)
(Note 7)
I
SD
Shutdown Current
V
PIN5
= 0V
0.01
A (max)
V
OS
Output Offset Voltage
V
IN
= 0V
5
mV (max)
P
0
Output Power ( 8
)
Output Power ( 4
)
THD = 0.3% (max); f = 1 kHz
THD = 0.5% (max); f = 1 kHz
0.25
0.5
W
W
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.25 Wrms; A
VD
= 2; 20 Hz
f
20 kHz
0.25
%
PSRR
Power Supply Rejection Ratio
V
DD
= 2.5V to 2.7V
65
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 func-
tional, but do not guarantee specific performance limits.
Electrical Characteristics
state DC and AC electrical specifications under particular test conditions which guar-
antee 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 LM4877, T
JMAX
= 150C. The
typical junction-to-ambient thermal resistance is 150C/W.
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: Low Voltage Circuit - See Fig. 4
Note 9: Shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase I
SD
by a maximum of 2A.
Electrical Characteristics V
DD
= 5/3.3/2.6V Shutdown Input
Symbol
Parameter
Conditions
LM4877
Units
(Limits)
Typical
Limit
V
IH
Shutdown Input Voltage High
1.2
V(min)
V
IL
Shutdown Input Voltage Low
0.4
V(max)
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
.
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
.
LM4877
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3
Typical Performance Characteristics
THD+N vs Frequency
at 5V and 8
DS101290-3
THD+N vs Frequency
at 3.3V and 8
DS101290-6
THD+N vs Frequency
at 2.6V and 8
DS101290-5
THD+N vs Frequency
at 2.6V and 4
DS101290-4
THD+N vs Output Power
V
DD
= 5V
DS101290-7
THD+N vs Output Power
V
DD
= 3.3V
DS101290-8
LM4877
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4
Typical Performance Characteristics
(Continued)
THD+N vs
Output Power
2.6V at 8
DS101290-9
THD+N vs
Output Power
2.6V at 4
DS101290-10
Output Power vs
Supply Voltage
DS101290-11
Output Power vs
Load Resistance
DS101290-12
Power Derating Curve
DS101290-14
Power Dissipation vs
Output Power
V
DD
= 5V
DS101290-26
LM4877
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