LM4893 Boomer ® Audio Power Amplifier Series 1.1 Watt Audio Power Amplifier
LM4893
1.1 Watt Audio Power Amplifier
General Description
The LM4893 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 1.1 watt of continuous average power to an 8
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 LM4893 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 LM4893 features a low-power consumption global shut-
down mode, which is achieved by driving the shutdown pin
with logic low. Additionally, the LM4893 features an internal
thermal shutdown protection mechanism.
The LM4893 contains advanced pop & click circuitry which
eliminates noises which would otherwise occur during
turn-on and turn-off transitions.
The LM4893 is unity-gain stable and can be configured by
external gain-setting resistors.
Key Specifications
j
Improved PSRR at 5V, 3V, & 217Hz
62dB (typ)
j
Higher Power Output at 5V & 1% THD
1.1W (typ)
j
Higher Power Output at 3V & 1% THD
350mW (typ)
j
Shutdown Current
0.1A (typ)
Features
n
No output coupling capacitors, snubber networks or
bootstrap capacitors required
n
Unity gain stable
n
Ultra low current shutdown mode
n
Instantaneous turn-on time
n
BTL output can drive capacitive loads up to 100pF
n
Advanced pop & click circuitry eliminates noises during
turn-on and turn-off transitions
n
2.2V - 5.5V operation
n
Available in space-saving SMD, SO, and MSOP
packages
Applications
n
Mobile Phones
n
PDAs
n
Portable electronic devices
Typical Application
Boomer
is a registered trademark of National Semiconductor Corporation.
20038001
FIGURE 1. Typical Audio Amplifier Application Circuit
August 2002
LM4893
1.1
W
att
Audio
Power
Amplifier
2002 National Semiconductor Corporation
DS200380
www.national.com
Connection Diagrams
9 Bump micro SMD
20038086
Top View
Order Number LM4893ITL, LM4893ITLX
See NS Package Number TLA09AAA
Small Outline (SO) Package
20038091
Top View
Order Number LM4893M
See NS package Number M08A
Mini Small Outline (MSOP) Package
20038084
Top View
NC = No Connect
Order Number LM4893MM
See NS Package Number MUB10A
9 Bump micro SMD Marking
20038087
Top View
X - Date Code
T - Die Traceability
G - Boomer Family
93 - LM4893ITL
SO Marking
20038092
Top View
XY - Date Code
TT - Die Traceability
Bottom 2 lines - Part Number
MSOP Marking
20038085
Top View
G - Boomer Family
93 - LM4893MM
LM4893
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 9)
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)
2000V
ESD Susceptibility (Note 5)
200V
Junction Temperature
150C
Thermal Resistance
JA
(TLA09AAA)
180C/W (Note 10)
JC
(MUB10A)
56C/W
JA
(MUB10A)
190C/W
JC
(M08A)
35C/W
JA
(M08A)
150C/W
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
LM4893
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 8)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, 8
BTL
5
10
mA (max)
I
SD
Shutdown Current
V
shutdown
= GND
0.1
2.0
A (max)
V
OS
Output Offset Voltage
5
40
mV (max)
P
o
Output Power
THD = 1% (max); f = 1kHz
1.1
0.9
W (min)
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.4Wrms; f = 1kHz
0.1
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mVsine p-p, C
B
=
1.0F
Input terminated with 10
to
ground
68 (f = 1kHz)
62 (f =
217Hz)
55
dB (min)
V
SDIH
Shutdown High Input Voltage
1.4
V (min)
V
SDIL
Shutdown Low Input Voltage
0.4
V (max)
N
OUT
Output Noise
A-Weighted; Measured across 8
BTL
Input terminated with 10
to
ground
26
V
RMS
Electrical Characteristics V
DD
= 3.0V
(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
LM4893
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 8)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, 8
BTL
4.5
9
mA (max)
I
SD
Shutdown Current
V
shutdown
= GND
0.1
2.0
A (max)
V
OS
Output Offset Voltage
5
40
mV (max)
P
o
Output Power
THD = 1% (max); f = 1kHz
350
320
mW
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.15Wrms; f = 1kHz
0.1
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mVsine p-p, C
B
=
1.0F
Input terminated with 10
to
ground
68 (f = 1kHz)
62 (f =
217Hz)
55
dB (min)
V
SDIH
Shutdown High Input Voltage
1.4
V (min)
V
SDIL
Shutdown Low Input Voltage
0.4
V (max)
LM4893
www.national.com
3
Electrical Characteristics V
DD
= 3.0V
(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
LM4893
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 8)
N
OUT
Output Noise
A-Weighted; Measured across 8
BTL
Input terminated with 10
to
ground
26
V
RMS
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
LM4893
Units
(Limits)
Typical
Limit
(Note 6)
(Notes 7, 8)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, 8
BTL
3.5
mA
I
SD
Shutdown Current
V
shutdown
= GND
0.1
A
V
OS
Output Offset Voltage
5
mV
P
o
Output Power
THD = 1% (max); f = 1kHz
R
L
= 8
250
mW
R
L
= 4
350
THD+N
Total Harmonic Distortion+Noise
P
o
= 0.1Wrms; f = 1kHz
0.1
%
PSRR
Power Supply Rejection Ratio
V
ripple
= 200mVsine p-p, C
B
=
1.0F
Input terminated with 10
to
ground
55 (f = 1kHz)
55 (f =
217Hz)
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 LM4893, 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, 220pF240pF 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: 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 part will be protected. If the part is enabled when V
DD
is above 6V, circuit performance will
be curtailed or the part may be permanently damaged.
Note 10: All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance.
Note 11: Maximum power dissipation (P
DMAX
) in the device occurs at an output power level significantly below full output power. P
DMAX
can be calculated using
Equation 1 shown in the Application section. It may also be obtained from the power dissipation graphs.
LM4893
www.national.com
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 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
THD+N vs Frequency
at V
DD
= 5V, 8
R
L
, and PWR = 250mW
THD+N vs Frequency
at V
DD
= 3.0V, 8
R
L
, and PWR = 150mW
20038037
20038038
THD+N vs Frequency
at V
DD
= 2.6V, 8
R
L
, and PWR = 100mW
THD+N vs Frequency
at V
DD
= 2.6V, 4
R
L
, and PWR = 100mW
20038039
20038040
LM4893
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5
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