National Semiconductor LM4904 Technical data
LM4904
1 Watt Audio Power Amplifier
LM4904 1 Watt Audio Power Amplifier
May 2004
General Description
The LM4904 is an audio power amplifier primarily designed
for demanding applications in mobile phones and other portable communication device applications. It is capable of
delivering 1 watt of continuous average power to an 8Ω BTL
load with less than 1% distortion (THD+N) 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. The LM4904 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for mobile phone and other low voltage applications where minimal power consumption is a primary requirement.
The LM4904 features a low-power consumption shutdown
mode, which is achieved by driving the shutdown pin with
logic high. Additionally, the LM4904 features an internal thermal shutdown protection mechanism.
The LM4904 contains advanced pop & click circuitry which
eliminates noise which would otherwise occur during turn-on
and turn-off transitions.
The LM4904 is unity-gain stable and can be configured by
external gain-setting resistors.
DC
Key Specifications
j
Improved PSRR at 217Hz & 1KHz 62dB
j
Power Output at 5.0V, 1% THD, 8Ω 1.07W (typ)
j
Power Output at 3.0V, 1% THD, 4Ω 525mW (typ)
j
Power Output at 3.0V, 1% THD, 8Ω 390mW (typ)
j
Shutdown Current 0.1µA (typ)
Features
n Available in space-saving micro SMD package
n Ultra low current shutdown mode
n BTL output can drive capacitive loads
n Improved pop & click circuitry eliminates noise during
turn-on and turn-off transitions
n 2.0 - 5.5V operation
n No output coupling capacitors, snubber networks or
bootstrap capacitors required
n Unity-gain stable
n External gain configuration capability
Applications
n Mobile Phones
n PDAs
n Portable electronic devices
Typical Application
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer®is a registered trademark of National Semiconductor Corporation.
200437B6
© 2004 National Semiconductor Corporation DS200437 www.national.com
Connection Diagrams
LM4904
8 Bump micro SMD
Top View
200437B4
Order Number LM4904ITL, LM4904ITLX
See NS Package Number TLA08AAA
8 Bump micro SMD Marking
Top View
200437C5
X - Date Code
T - Dice Traceability
G - Boomer Family
A6 - LM4904ITL
www.national.com 2
LM4904
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 11) 6.0V
Thermal Resistance
θ
(micro SMD) (Note 12) 210˚C/W
JA
Soldering Information
See AN-1112 "microSMD Wafers Level Chip Scale
Package."
Storage Temperature −65˚C to +150˚C
Input Voltage −0.3V to V
DD
+0.3V
Operating Ratings
Power Dissipation (Notes 3, 13) Internally Limited
ESD Susceptibility (Note 4) 2000V
ESD Susceptibility (Note 5) 200V
Junction Temperature 150˚C
Temperature Range
T
≤ TA≤ T
MIN
MAX
Supply Voltage 2.0V ≤ V
Electrical Characteristics VDD=5V (Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
LM4904
Symbol Parameter Conditions
= 0V, Io= 0A, No Load 3 7 mA (max)
V
I
DD
I
SD
V
SDIH
V
SDIL
V
OS
R
OUT
P
o
T
WU
Quiescent Power Supply Current
Shutdown Current VSD=VDD(Note 8) 0.1 2.0 µA (max)
Shutdown Voltage Input High 1.5 V (min)
Shutdown Voltage Input Low 1.3 V (max)
Output Offset Voltage 7 50 mV (max)
Resistor Output to GND (Note 10) 8.5
Output Power THD = 1% (max);f=1kHz 1.07 0.9 W
Wake-up time 100 mS (max)
THD+N Total Harmonic Distortion+Noise P
PSRR Power Supply Rejection Ratio
IN
V
= 0V, Io= 0A, 8Ω Load 4 10 mA (max)
IN
= 0.5 Wrms; f = 1kHz 0.2 %
o
V
= 200mV sine p-p
ripple
Input terminated with 10Ω
Typical Limit
(Note 6) (Notes 7, 9)
60 (f =
217Hz)
64 (f = 1kHz)
9.7 kΩ (max)
7.0 kΩ (min)
55 dB (min)
−40˚C ≤ TA≤ 85˚C
≤ 5.5V
DD
= 25˚C.
A
Units
(Limits)
Electrical Characteristics VDD=3V (Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
LM4904
Symbol Parameter Conditions
= 0V, Io= 0A, No Load 2 7 mA (max)
V
I
DD
I
SD
V
SDIH
V
SDIL
V
OS
R
OUT
P
o
T
WU
Quiescent Power Supply Current
Shutdown Current VSD=VDD(Note 8) 0.1 2.0 µA (max)
Shutdown Voltage Input High 1.1 V (min)
Shutdown Voltage Input Low 0.9 V (max)
Output Offset Voltage 7 50 mV (max)
Resistor Output to GND (Note 10) 8.5
Output Power (8Ω) THD = 1% (max);f=1kHz 390 mW
(4Ω) THD = 1% (max);f=1kHz 525
Wake-up time 75 mS (max)
THD+N Total Harmonic Distortion+Noise P
PSRR Power Supply Rejection Ratio
IN
V
= 0V, Io= 0A, 8Ω Load 3 9 mA (max)
IN
= 0.25 Wrms; f = 1kHz 0.1 %
o
V
= 200mV sine p-p
ripple
Input terminated with 10Ω
Typical Limit
(Note 6) (Notes 7, 9)
62 (f =
217Hz)
68 (f = 1kHz)
9.7 kΩ (max)
7.0 kΩ (min)
55 dB (min)
= 25˚C.
A
www.national.com3
Units
(Limits)
Electrical Characteristics VDD= 2.6V (Notes 1, 2)
The following specifications apply for the circuit shown in Figure 1, unless otherwise specified. Limits apply for T
LM4904
LM4904
Symbol Parameter Conditions
= 0V, Io= 0A, No Load 2.0 mA (max)
V
I
DD
I
SD
V
SDIH
V
SDIL
V
OS
R
OUT
P
o
Quiescent Power Supply Current
Shutdown Current VSD=VDD(Note 8) 0.1 µA (max)
Shutdown Voltage Input High 1.0 V (min)
Shutdown Voltage Input Low 0.9 V (max)
Output Offset Voltage 5 50 mV (max)
Resistor Output to GND (Note 10) 8.5
Output Power ( 8Ω ) THD = 1% (max);f=1kHz 275
IN
V
= 0V, Io= 0A, 8Ω Load 3.0 mA (max)
IN
(4Ω ) THD = 1% (max);f=1kHz 340
T
WU
THD+N Total Harmonic Distortion+Noise P
PSRR Power Supply Rejection Ratio
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 andAC 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
allowable power dissipation is P
curves for additional information.
Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 5: Machine Model, 220 pF–240 pF discharged through all pins.
Note 6: Typicals are measured at 25˚C 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
Note 9: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 10: R
Note 11: If the product is in Shutdown mode and V
If the source impedance limits the current to a max of 10mA, then the device will be protected. If the device is enabled when V
6.5V, no damage will occur, although operation life will be reduced. Operation above 6.5V with no current limit will result in permanent damage.
Note 12: All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The LM4904ITL demo board (views featured
in the Application Information section) has two inner layers, one for V
and aid in spreading heat due to power dissipation within the IC.
Note 13: Maximum power dissipation in the device (P
Equation 1 shown in the Application Information section. It may also be obtained from the power dissipation graphs.
Wake-up time 70 mS (max)
= 0.15 Wrms; f = 1kHz 0.1 %
o
V
= 200mV sine p-p
ripple
Input terminated with 10Ω
=(T
DMAX
is measured from the output pin to ground. This value represents the parallel combination of the 10kΩ output resistors and the two 20kΩ resistors.
ROUT
)/θJAor the number given inAbsolute Maximum Ratings, whichever is lower. For the LM4904, see power derating
JMAX–TA
exceeds 6V (to a max of 8V VDD), then most of the excess current will flow through the ESD protection circuits.
DD
and one for GND. The planes each measure 600mils x 600mils (15.24mm x 15.24mm)
DD
) occurs at an output power level significantly below full output power. P
DMAX
Typical Limit
(Note 6) (Notes 7, 9)
9.7 kΩ (max)
7.0 kΩ (min)
51 (f =
217Hz)
51 (f = 1kHz)
, θJA, and the ambient temperature TA. The maximum
JMAX
by a maximum of 2µA.
SD
is greater than 5.5V and less than
DD
can be calculated using
DMAX
= 25˚C.
A
Units
(Limits)
mW
dB (min)
www.national.com 4
External Components Description
(Figure 1)
Components Functional Description
1. R
2. C
3. R
4. C
Inverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a
i
high pass filter with C
Input coupling capacitor which blocks the DC voltage at the amplifiers input terminals. Also creates a
i
highpass filter with R
for an explanation of how to determine the value of C
Feedback resistance which sets the closed-loop gain in conjunction with Ri.
f
Supply bypass capacitor which provides power supply filtering. Refer to the Power Supply Bypassing
S
at fC= 1/(2π RiCi).
i
at fc= 1/(2π RiCi). Refer to the section, Proper Selection of External Components,
i
.
i
section for information concerning proper placement and selection of the supply bypass capacitor.
5. C
Bypass pin capacitor which provides half-supply filtering. Refer to the section, Proper Selection of External
B
Components, for information concerning proper placement and selection of C
Typical Performance Characteristics
LM4904
.
B
THD+N vs Frequency
= 5V, 8Ω RL, and PWR = 500mW
at V
DD
THD+N vs Frequency
= 2.6V, 8Ω RL, and PWR = 150mW
at V
DD
THD+N vs Frequency
at VDD= 3V, 8Ω RL, and PWR = 250mW
20043730 20043731
THD+N vs Frequency
at VDD= 2.6V, 4Ω RL, and PWR = 150mW
20043732 20043733
www.national.com5
Typical Performance Characteristics (Continued)
LM4904
THD+N vs Power Out
at V
= 5V, 8Ω RL, 1kHz
DD
THD+N vs Power Out
= 2.6V, 8Ω RL, 1kHz
at V
DD
THD+N vs Power Out
at VDD= 3V, 8Ω RL, 1kHz
20043734 20043783
THD+N vs Power Out
at VDD= 2.6V, 4Ω RL, 1kHz
20043784 20043785
Power Supply Rejection Ratio (PSRR) vs Frequency
= 5V, 8Ω R
at V
DD
L
20043786
Input terminated with 10Ω
Power Supply Rejection Ratio (PSRR) vs Frequency
= 5V, 8Ω R
at V
DD
L
20043787
Input Floating
www.national.com 6
Loading...