LM4835
Stereo 2W Audio Power Amplifiers
with DC Volume Control and Selectable Gain
General Description
The LM4835 is a monolithic integrated circuit that provides
DC volume control, and stereo bridged audio power amplifi-
ers capable of producing 2W into 4
(Note 1) with less than
1.0% THD or 2.2W into 3
(Note 2) with less than 1.0%
THD.
Boomer
audio integrated circuits were designed specifically
to provide high quality audio while requiring a minimum
amount of external components. The LM4835 incorporates a
DC volume control, stereo bridged audio power amplifiers
and a selectable gain or bass boost, making it optimally
suited for multimedia monitors, portable radios, desktop, and
portable computer applications.
The LM4835 features an externally controlled, low-power
consumption shutdown mode, and both a power amplifier
and headphone mute for maximum system flexibility and
performance.
Note 1: When properly mounted to the circuit board, the LM4835LQ and
LM4835MTE will deliver 2W into 4
. The LM4835MT will deliver 1.1W into
8
. See the Application Information section LM4835LQ and for LM4835MTE
usage information.
Note 2: An LM4835LQ and LM4835MTE that have been properly mounted
to the circuit board and forced-air cooled will deliver 2.2W into 3
.
Key Specifications
n
P
O
at 1% THD+N
n
into 3
(LM4835LQ, LM4835MTE)
2.2W (typ)
n
into 4
(LM4835LQ, LM4835MTE)
2.0W (typ)
n
into 8
(LM4835)
1.1W (typ)
n
Single-ended mode - THD+N at 85mW into 32
1.0%
(typ)
n
Shutdown current
0.7A (typ)
Features
n
PC98 Compliant
n
DC Volume Control Interface
n
System Beep Detect
n
Stereo switchable bridged/single-ended power amplifiers
n
Selectable internal/external gain and bass boost
configurable
n
"Click and pop" suppression circuitry
n
Thermal shutdown protection circuitry
Applications
n
Portable and Desktop Computers
n
Multimedia Monitors
n
Portable Radios, PDAs, and Portable TVs
Connection Diagrams
LLP Package
TSSOP Package
10013935
Top View
Order Number LM4835LQ
See NS Package LQA028AA for Exposed-DAP LLP
10013902
Top View
Order Number LM4835MT or LM4835MTE
See NS Package MTC28 for TSSOP
or See NS Package MXA28A for Exposed-DAP TSSOP
Boomer
is a registered trademark of NationalSemiconductor Corporation.
February 2003
LM4835
Stereo
2W
Audio
Power
Amplifiers
with
DC
V
olume
Control
and
Selectable
Gain
2003 National Semiconductor Corporation
DS100139
www.national.com
Absolute Maximum Ratings
(Note 12)
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
Internally limited
ESD Susceptibility (Note 14)
2000V
ESD Susceptibility (Note 15)
200V
Junction Temperature
150C
Soldering Information
Small Outline Package
Vapor Phase (60 sec.)
215C
Infrared (15 sec.)
220C
See AN-450 "Surface Mounting and their Effects on
Product Reliability" for other methods of soldering surface
mount devices.
JC
(typ) -- LQA028AA
3.0C/W
JA
(typ) -- LQA028AA (Note 7)
42C/W
JC
(typ) -- MTC28
20C/W
JA
(typ) -- MTC28
80C/W
JC
(typ) -- MXA28A
2C/W
JA
(typ) -- MXA28A (Note 4)
41C/W
JA
(typ) -- MXA28A (Note 3)
54C/W
JA
(typ) -- MXA28A (Note 5)
59C/W
JA
(typ) -- MXA28A (Note 6)
93C/W
Operating Ratings
Temperature Range
T
MIN
T
A
T
MAX
-40C
TA 85C
Supply Voltage
2.7V
V
DD
5.5V
Electrical Characteristics for Entire IC
(Notes 8, 12) The following specifications apply for V
DD
= 5V unless otherwise noted. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4835
Units
(Limits)
Typical
(Note 16)
Limit
(Note 17)
V
DD
Supply Voltage
2.7
V (min)
5.5
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
O
= 0A
15
30
mA (max)
I
SD
Shutdown Current
V
pin 2
= V
DD
0.7
2.0
A (max)
V
IH
Headphone Sense High Input Voltage
4
V (min)
V
IL
Headphone Sense Low Input Voltage
0.8
V (max)
Electrical Characteristics for Volume Attenuators
(Notes 8, 12) The following specifications apply for V
DD
= 5V. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4835
Units
(Limits)
Typical
(Note 16)
Limit
(Note 17)
C
RANGE
Attenuator Range
Gain with V
pin 7
= 5V
0
0.5
dB (max)
Attenuation with V
pin 7
= 0V
-81
-80
dB (min)
A
M
Mute Attenuation
V
pin 5
= 5V, Bridged Mode
-88
-80
dB (min)
V
pin 5
= 5V, Single-Ended Mode
-88
-80
dB (min)
Electrical Characteristics for Single-Ended Mode Operation
(Notes 8, 12) The following specifications apply for V
DD
= 5V. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4835
Units
(Limits)
Typical
(Note 16)
Limit
(Note 17)
P
O
Output Power
THD = 1.0%; f = 1kHz; R
L
= 32
85
mW
THD = 10%; f = 1 kHz; R
L
= 32
95
mW
THD+N
Total Harmonic Distortion+Noise
V
OUT
= 1V
RMS
, f=1kHz, R
L
= 10k
,
A
VD
= 1
0.065
%
PSRR
Power Supply Rejection Ratio
C
B
= 1.0 F, f =120 Hz,
V
RIPPLE
= 200 mVrms
58
dB
LM4835
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3
Electrical Characteristics for Single-Ended Mode Operation
(Continued)
(Notes 8, 12) The following specifications apply for V
DD
= 5V. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4835
Units
(Limits)
Typical
(Note 16)
Limit
(Note 17)
SNR
Signal to Noise Ratio
P
OUT
=75 mW, R
L
= 32
, A-Wtd
Filter
102
dB
X
talk
Channel Separation
f=1kHz, C
B
= 1.0 F
65
dB
Electrical Characteristics for Bridged Mode Operation
(Notes 8, 12) The following specifications apply for V
DD
= 5V, unless otherwise noted. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4835
Units
(Limits)
Typical
(Note 16)
Limit
(Note 17)
V
OS
Output Offset Voltage
V
IN
= 0V
5
30
mV (max)
P
O
Output Power
THD + N = 1.0%; f=1kHz; R
L
= 3
(Notes 9, 11)
2.2
W
THD + N = 1.0%; f=1kHz; R
L
= 4
(Notes 10, 11)
2
W
THD = 0.5% (max);f = 1 kHz;
R
L
= 8
1.1
1.0
W (min)
THD+N = 10%;f = 1 kHz; R
L
= 8
1.5
W
THD+N
Total Harmonic Distortion+Noise
P
O
= 1W, 20 Hz
<
f
<
20 kHz,
R
L
= 8
, A
VD
= 2
0.3
%
P
O
= 340 mW, R
L
= 32
1.0
%
PSRR
Power Supply Rejection Ratio
C
B
= 1.0 F, f = 120 Hz,
V
RIPPLE
= 200 mVrms; R
L
= 8
74
dB
SNR
Signal to Noise Ratio
V
DD
= 5V, P
OUT
= 1.1W, R
L
= 8
,
A-Wtd Filter
93
dB
X
talk
Channel Separation
f=1kHz, C
B
= 1.0 F
70
dB
Note 3: The
JA
given is for an MXA28A package whose exposed-DAP is soldered to an exposed 2in
2
piece of 1 ounce printed circuit board copper.
Note 4: The
JA
given is for an MXA28A package whose exposed-DAP is soldered to a 2in
2
piece of 1 ounce printed circuit board copper on a bottom side layer
through 21 8mil vias.
Note 5: The
JA
given is for an MXA28A package whose exposed-DAP is soldered to an exposed 1in
2
piece of 1 ounce printed circuit board copper.
Note 6: The
JA
given is for an MXA28A package whose exposed-DAP is not soldered to any copper.
Note 7: The given
JA
is for an LM4835 packaged in an LQA24A with the exposed-DAP soldered to an exposed 2in
2
area of 1oz printed circuit board copper.
Note 8: All voltages are measured with respect to the ground pins, unless otherwise specified. All specifications are tested using the typical application as shown
in Figure 1.
Note 9: When driving 3
loads and operating on a 5V supply, the LM4835MTE must be mounted to the circuit board and forced-air cooled.
Note 10: When driving 4
loads and operating on a 5V supply, the LM4835MTE must be mounted to the circuit board.
Note 11: When driving a 3
or 4 loads and operating on a 5V supply, the LM4835LQ must be mounted to the circuit board that has a minimum of 2.5in
2
of
exposed, uninterrupted copper area connected to the LLP package's exposed DAP.
Note 12: 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 13: 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 LM4835LQ and LM4835MT, T
JMAX
= 150C, and the typical junction-to-ambient thermal
resistance, when board mounted, is 80C/W for the MTC28 package and 42C/W for the LM4835LQ package.
Note 14: Human body model, 100pF discharged through a 1.5k
resistor.
Note 15: Machine Model, 220pF240pF discharged through all pins.
Note 16: Typicals are measured at 25C and represent the parametric norm.
Note 17: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
LM4835
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