LM4801
1W Stereo Audio Amplifier Plus Adjustable LDO
General Description
The LM4801 combines a bridge-connected (BTL) stereo
audio power amplifier with a low dropout voltage regulator
(LDO). The audio amplifier delivers 1.0W to a 8
load with a
less than 1.0% THD+N while operating on a 5V power
supply.
With the LM4801's adjustable low-dropout (LDO) CMOS
linear regulator delivers an output current of up to 300mA,
has shutdown mode (1nA, typ) low quiescent current (90A,
typ) and LDO voltage (120mV, typ). The regulator is stable
with small ceramic capacitive load (2.2F, typ). The regulator
includes regulation fault detection, a bandgap voltage refer-
ence, and constant current limiting. It is designed for low
power, low current applications that can take advantage of
its 300mA output current capability.
The LM4801 features an externally controlled micropower
shutdown mode and thermal shutdown protection. It also
utilizes circuitry that reduces "clicks and pops" during device
turn-on and return from shutdown.
Boomer audio power amplifiers are designed specifically to
use few external components and provide high quality output
power in a surface mount package.
Key Specifications
n
P
O
(BTL): V
DD
= 5V, THD+N
1%, R
L
= 8
1.0W(typ)
n
Power supply range (amplifier)
3.0V to 5.0V
n
Power supply range (LDO)
2.5V to 6.0V
n
Shutdown current
0.07A (typ)
n
LDO output current
300mA (min)
n
LDO dropout voltage (I
OUT
= 300mA)
120mV (typ)
n
LDO quiescent supply current
90A (typ)
n
LDO shutdown supply current
1nA (typ)
n
LDO PSRR
60dB
n
LDO turn-on time
120ms (typ)
n
LDO ouput noise-voltage
37V
RMS
(typ)
Features
n
Stereo BTL amplifier
n
Adjustable LDO regulator
n
"Click and pop" suppression circuitry
n
LDO is stable with small-value ceramic output capacitors
n
Unity-gain stable audio amplifiers
n
LDO has over-current protection
n
Thermal shutdown protection circuitry
n
TSSOP (MH) package
Applications
n
Multimedia monitors
n
Portable and desktop computers
n
Portable televisions
Connection Diagram
20073629
Top View
Order Number LM4801MH
See NS Package Number MXA28A for TSSOP
Boomer
is a registered trademark of National Semiconductor Corporation.
September 2003
LM4801
1W
Stereo
Audio
Amplifier
Plus
Adjustable
LDO
2003 National Semiconductor Corporation
DS200736
www.national.com
Absolute Maximum Ratings
Stereo Amplifier
(Notes 1, 5)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Amplifier Supply Voltage (pins 5, 24)
6.0V
LDO-V
CC
, LDO-OUT, LDO-SHDN,
ADJ, CC, FAULT (pins 11-15, 17,19)
-0.3V to 6.5V
Fault Sink Current
20mA
Storage Temperature
-65C to +150C
Input Voltage
-0.3V to V
DD
+0.3V
Power Dissipation (Note 2)
Internally limited
ESD Susceptibility(Note 3)
2000V
ESD Susceptibility (Note 4)
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) -- MXA28A
20C/W
JA
(typ) -- MXA28A (Note 2)
41C/W
Operating Ratings
Temperature Range
T
MIN
T
A
T
MAX
-40C
T
A
85C
Supply Voltage
Pins 5, 24
3.0V
V
DD
5.5V
Pin 17
2.5V
V
CC
6.0V
Stereo Amplifier Electrical Characteristics for Entire IC
(Notes 1, 5)
The following specifications apply for V
DD
= 5V unless otherwise noted. Limits apply for T
A
= 25C.
Symbol
Parameter
Conditions
LM4801
Units
(Limits)
Typical
Limit
(Note 6)
(Note 7)
V
DD
Supply Voltage
3
V (min)
5.5
V (max)
I
DD
Quiescent Power Supply Current
V
IN
= 0V, I
O
= 0A (Note 8)
8
20
3.5
mA (max)
mA (min)
I
SD
Shutdown Current
V
DD
applied to the SHUTDOWN pin
0.07
2
A (min)
V
OS
Output Offset Voltage
V
IN
= 0V
5
50
mV (max)
P
O
Output Power (Note 13)
THD+N = 1%, f = 1kHz, R
L
= 8
1.1
1.0
W (min)
THD+N = 10%, f = 1kHz, R
L
= 8
1.5
W
THD+N
Total Harmonic Distortion+Noise
20Hz
f 20kHz, A
VD
= 2
R
L
= 8
, P
O
= 1W
0.13
%
PSRR
Power Supply Rejection Ratio
V
DD
= 5V, V
RIPPLE
= 200mV
RMS
,
R
L
= 8
, C
B
= 1.0F
Inputs Floating
Inputs terminated with 10
67
43
dB
dB
X
TALK
Channel Separation
f = 1kHz, C
B
= 1.0F
90
dB
SNR
Signal To Noise Ratio
V
DD
= 5V, P
O
= 1W, R
L
= 8
98
dB
LDO Electrical Characteristics
Unless otherwise specified, all limits guaranteed for V
IN
= V
O
+0.5V (Note 10), V
SHDN
= V
IN
, C
IN
= C
OUT
= 2.2F, C
CC
= 33nF,
T
J
= 25C. Boldface limits apply for the operating temperature extremes: -40C and 85C.
Symbol
Parameter
Conditions
Min
(Note 7)
Typ
(Note 6)
Max
(Note 7)
Units
V
IN
Input Voltage
2.5
6.0
V
V
O
Output Voltage Tolerance
100A
I
OUT
300mA
V
IN
= V
O
+ 0.5V (Note 7)
SET = OUT
-2
+2
% of
V
OUT (NOM)
-3
+3
V
O
Output Adjust Range
1.25
6
V
I
O
Maximum Output Current
Average DC Current Rating
300
mA
I
LIMIT
Output Current Limit
330
770
mA
LM4801
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3
LDO Electrical Characteristics
(Continued)
Unless otherwise specified, all limits guaranteed for V
IN
= V
O
+0.5V (Note 10), V
SHDN
= V
IN
, C
IN
= C
OUT
= 2.2F, C
CC
= 33nF,
T
J
= 25C. Boldface limits apply for the operating temperature extremes: -40C and 85C.
Symbol
Parameter
Conditions
Min
(Note 7)
Typ
(Note 6)
Max
(Note 7)
Units
I
Q
Supply Current
I
OUT
= 0mA
90
270
A
I
OUT
= 300mA
225
Shutdown Supply Current
V
O
= 0V, SHDN = GND
0.001
1
A
V
DO
Dropout Voltage
(Note 10), (Note 11)
I
OUT
= 1mA
0.4
mV
I
OUT
= 200mA
80
220
I
OUT
= 300mA
120
V
O
Line Regulation
I
OUT
= 1mA, (V
O
+ 0.5V)
V
I
6V
(Note 10)
-0.1
0.01
0.1
%/V
Load Regulation
100A
I
OUT
300mA
0.002
%/mA
e
n
Output Voltage Noise
I
OUT
= 10mA, 10Hz
f 100kHz
37
V
RMS
Output Voltage Noise Density
10Hz
f 100kHz, C
OUT
= 10F
190
nV/
V
SHDN
SHDN Input Threshold
V
IH
, (V
O
+ 0.5V)
V
I
6V
(Note 10)
2
V
V
IL
, (V
O
+ 0.5V)
V
I
6V
0.4
I
SHDN
SHDN Input Bias Current
SHDN = GND or IN
0.1
100
nA
I
SET
SET Input Leakage
SET = 1.3V
0.1
2.5
nA
V
FAULT
FAULTDetection Voltage
V
O
2.5V, I
OUT
= 200mA (Note
12)
120
280
mV
FAULT Output Low Voltage
I
SINK
= 2mA
0.115
0.25
V
I
FAULT
FAULT Off-Leakage Current
FAULT = 3.6V, SHDN = 0V
0.1
100
nA
T
SD
Thermal Shutdown
Temperature
160
C
Thermal Shutdown Hysteresis
10
T
ON
Start-Up Time
C
OUT
= 10F, V
O
at 90% of Final
Value
120
s
Note 1: 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 2: The maximum power dissipation is dictated by T
JMAX
,
JA
, and the ambient temperature T
A
and must be derated at elevated temperatures. The maximum
allowable power dissipation is P
DMAX
= (T
JMAX
- T
A
)/
JA
. For the LM4801, T
JMAX
= 150C. The
JA
for the LM4801 in the 28-pin MXA28A package, when board
mounted and its DAP is soldered to a 2in
2
copper heatsink plane, is 41C/W.
Note 3: Human body model, 100pF discharged through a 1.5k
resistor.
Note 4: Machine model, 220pF240pF discharged through all pins.
Note 5: All voltages are measured with respect to the ground (GND) pins unless otherwise specified.
Note 6: Typicals are measured at 25C and represent the parametric norm.
Note 7: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 8: The quiescent power supply current depends on the offset voltage when a practical load is connected to the amplifier.
Note 9: Output power is measured at the device terminals.
Note 10: Condition does not apply to input voltages below 2.5V since this is the minimum input operating voltage.
Note 11: Dropout voltage is measured by reducing V
IN
until V
O
drops 100mV from its nominal value at V
IN
-V
O
= 0.5V. Dropout Voltage does not apply to the 1.8
version.
Note 12: The FAULT detection voltage is specified for the input to output voltage differential at which the FAULT pin goes active low.
LM4801
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