LM4863
Dual 2.2W Audio Amplifier Plus Stereo Headphone
Function
General Description
The LM4863 is a dual bridge-connected audio power ampli-
fier which, when connected to a 5V supply, will deliver 2.2W
to a 4
load (Note 1) or 2.5W to a 3
load (Note 2)with less
than 1.0% THD+N. In addition, the headphone input pin al-
lows the amplifiers to operate in single-ended mode to drive
stereo headphones.
Boomer audio power amplifiers were designed specifically to
provide high quality output power from a surface mount
package while requiring few external components. To sim-
plify audio system design, the LM4863 combines dual bridge
speaker amplifiers and stereo headphone amplifiers on one
chip.
The LM4863 features an externally controlled, low-power
consumption shutdown mode, a stereo headphone amplifier
mode, and thermal shutdown protection. It also utilizes cir-
cuitry to reduce "clicks and pops" during device turn-on.
Note 1:
An LM4863MTE which has been properly mounted to the circuit
board will deliver 2.2W into 4
. The other package options for the LM4863
will deliver 1.1W into 8
. See the Application Information section for
LM4863MTE usage information.
Note 2: An LM4863MTE which has been properly mounted to the circuit
board and forced-air cooled will deliver 2.5W into 3
.
Key Specifications
n
P
O
at 1% THD+N
into 3
(LM4863MTE)
2.5W(typ)
into 4
(LM4863MTE)
2.2W(typ)
into 8
(LM4863)
1.1W(typ)
n
Single-ended mode - THD+N
at 75mW into 32
0.5%(max)
n
Shutdown current
0.7A(typ)
Features
n
Stereo headphone amplifier mode
n
"Click and pop" suppression circuitry
n
Unity-gain stable
n
Thermal shutdown protection circuitry
n
Exposed-DAP TSSOP, TSSOP, SOIC and DIP
packaging available
Applications
n
Multimedia monitors
n
Portable and desktop computers
n
Portable televisions
Typical Application
Boomer
is a registered trademark of National Semiconductor Corporation.
DS012881-1
*
Refer to the section Proper Selection of External Components, for a detailed discussion of C
B
size.
FIGURE 1. Typical Audio Amplifier Application Circuit
October 1999
LM4863
Dual
2.2W
Audio
Amplifier
Plus
Stereo
Headphone
Function
1999 National Semiconductor Corporation
DS012881
www.national.com
Connection Diagrams
DS012881-28
Top View
Order Number LM4863M, LM4863N
See NS Package Number M16B for SO
See NS Package Number N16A for DIP
DS012881-29
Top View
Order Number LM4863MT
See NS Package Number MTC20 for TSSOP
DS012881-2
Top View
Order Number LM4863MTE
See NS Package Number MXA20A for Exposed-DAP TSSOP
LM4863
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2
Absolute Maximum Ratings
(Note 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 10)
Internally limited
ESD Susceptibility (Note 11)
2000V
ESD Susceptibility (Note 12)
200V
Junction Temperature
150C
Solder Information
Small Outline Package
Vapor Phase (60 sec.)
215C
Infrared (15 sec.)
220C
See AN-450 "Surface Mounting and their Effects on
Product Reliablilty" for other methods of soldering surface
mount devices.
Thermal Resistance
JC
(typ) -- M16B
20C/W
JA
(typ) -- M16B
80C/W
JC
(typ) -- N16A
20C/W
JA
(typ) -- N16A
63C/W
JC
(typ) -- MTC20
20C/W
JA
(typ) -- MTC20
80C/W
JC
(typ) -- MXA20A
2C/W
JA
(typ) -- MXA20A
41C/W (Note 7)
JA
(typ) -- MXA20A
51C/W (Note 5)
JA
(typ) -- MXA20A
90C/W (Note 6)
Operating Ratings
Temperature Range
T
MIN
T
A
T
MAX
-40C
T
A
85C
Supply Voltage
2.0V
V
DD
5.5V
Electrical Characteristics for Entire IC
(Notes 3, 4)
The following specifications apply for V
DD
= 5V unless otherwise noted. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4863
Units
(Limits)
Typical
Limit
(Note 13)
(Note 14)
V
DD
Supply Voltage
2
V (min)
5.5
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
O
= 0A (Note 15) , HP-IN = 0V
11.5
20
mA (max)
6
mA (min)
V
IN
= 0V, I
O
= 0A (Note 15) , HP-IN = 4V
5.8
mA
I
SD
Shutdown Current
V
PIN1
= V
DD
0.7
2
A (min)
V
IH
Headphone High Input Voltage
4
V (min)
V
IL
Headphone Low Input Voltage
0.8
V (max)
Electrical Characteristics for Bridged-Mode Operation
(Notes 3, 4)
The following specifications apply for V
DD
= 5V unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4863
Units
(Limits)
Typical
Limit
(Note
13)
(Note
14)
V
OS
Output Offset Voltage
V
IN
= 0V
5
50
mV (max)
P
O
Output Power (Note 9)
THD = 1%, f = 1 kHz
LM4863MTE, R
L
= 3
(Note 7)
2.5
W
LM4863MTE, R
L
= 4
(Note 8)
2.2
W
LM4863, R
L
= 8
1.1
1.0
W (min)
THD+N = 10%, f = 1 kHz
LM4863MTE, R
L
= 3
(Note 7)
3.2
W
LM4863MTE, R
L
= 4
(Note 8)
2.7
LM4863, R
L
= 8
1.5
W
THD+N = 1%, f = 1 kHz, R
L
= 32
0.34
W
THD+N
Total Harmonic Distortion+Noise
20 Hz
f
20 kHz, A
VD
= 2
LM4863MTE, R
L
= 4
, P
O
= 2W
0.3
LM4863, R
L
= 8
, P
O
= 1W
0.3
%
PSRR
Power Supply Rejection Ratio
V
DD
= 5V, V
RIPPLE
= 200 mV
RMS
, R
L
= 8
,
C
B
= 1.0 F
67
dB
LM4863
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3
Electrical Characteristics for Bridged-Mode Operation
(Notes 3, 4) (Continued)
The following specifications apply for V
DD
= 5V unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4863
Units
(Limits)
Typical
Limit
(Note
13)
(Note
14)
X
TALK
Channel Separation
f = 1 kHz, C
B
= 1.0 F
90
dB
SNR
Signal To Noise Ratio
V
DD
= 5V, P
O
= 1.1W, R
L
= 8
98
dB
Electrical Characteristics for Single-Ended Operation
(Notes 3, 4)
The following specifications apply for V
DD
= 5V unless otherwise specified. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4863
Units
(Limits)
Typical
Limit
(Note
13)
(Note
14)
V
OS
Output Offset Voltage
V
IN
= 0V
5
50
mV (max)
P
O
Output Power
THD = 0.5%, f = 1 kHz, R
L
= 32
85
75
mW (min)
THD+N = 1%, f = 1 kHz, R
L
= 8
340
mW
THD+N = 10%, f = 1 kHz, R
L
= 8
440
mW
THD+N
Total Harmonic Distortion+Noise
A
V
= -1, P
O
= 75 mW, 20 Hz
f
20 kHz,
R
L
= 32
0.2
%
PSRR
Power Supply Rejection Ratio
C
B
= 1.0 F, V
RIPPLE
= 200 mV
RMS
,
f = 1 kHz
52
dB
X
TALK
Channel Separation
f = 1 kHz, C
B
= 1.0 F
60
dB
SNR
Signal To Noise Ratio
V
DD
= 5V, P
O
= 340mW, R
L
= 8
95
dB
Note 3: All voltages are measured with respect to the ground pins, 2, 7, and 15, 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 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 5: The
JA
given is for an MXA20A package whose exposed-DAP is soldered to an exposed 2in
2
piece of 1 ounce printed circuit board copper.
Note 6: The
JA
given is for an MXA20A package whose exposed-DAP is not soldered to any copper.
Note 7: When driving 3
loads from a 5V supply, the LM4863MTE must be mounted to the circuit board and forced-air cooled (450 linear-feet per minute).
Note 8: When driving 4
loads from a 5V supply, the LM4863MTE must be mounted to the circuit board.
Note 9: Output power is measured at the device terminals.
Note 10: 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
. For the LM4863, T
JMAX
= 150C. For the
JA
s for different packages, please see the Application Informa-
tion section or the Absolute Maximum Ratings section.
Note 11: Human body model, 100 pF discharged through a 1.5 k
resistor.
Note 12: Machine model, 220 pF240 pF discharged through all pins.
Note 13: Typicals are measured at 25C and represent the parametric norm.
Note 14: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
Note 15: The quiescent power supply current depends on the offset voltage when a practical load is connected to the amplifier.
Truth Table for Logic Inputs
SHUTDOWN
HP-IN
LM4863 MODE
Low
Low
Bridged
Low
High
Single-Ended
High
Low
LM4863 Shutdown
High
High
LM4863 Shutdown
LM4863
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4
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 amplifier's 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
MTE Specific Characteristics
Note 16: These curves show the thermal dissipation ability of the LM4863MTE at different ambient temperatures given these conditions:
500LFPM + JEDEC board: The part is soldered to a 1S2P 20-lead exposed-DAP TSSOP test board with 500 linear feet per minute of forced-air flow across
it. Board information - copper dimensions: 74x74mm, copper coverage: 100% (buried layer) and 12% (top/bottom layers), 16 vias under the exposed-DAP.
500LFPM + 2.5in
2
: The part is soldered to a 2.5in
2
, 1 oz. copper plane with 500 linear feet per minute of forced-air flow across it.
2.5in
2
: The part is soldered to a 2.5in
2
, 1oz. copper plane.
Not Attached: The part is not soldered down and is not forced-air cooled.
LM4863MTE
THD+N vs Output Power
DS012881-97
LM4863MTE
THD+N vs Frequency
DS012881-99
LM4863MTE
THD+N vs Output Power
DS012881-96
LM4863MTE
THD+N vs Frequency
DS012881-98
LM4863MTE
Power Dissipation vs Power Output
DS012881-90
LM4863MTE(Note 16)
Power Derating Curve
DS012881-95
LM4863
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