|
|
PDF LM4898ITL Data sheet ( Hoja de datos )
| Número de pieza | LM4898ITL | |
| Descripción | 1 Watt Fully Differential Audio Power Amplifier With Shutdown Select | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LM4898ITL (archivo pdf) en la parte inferior de esta página. Total 17 Páginas | ||
|
No Preview Available !
July 2003
LM4898
1 Watt Fully Differential Audio Power Amplifier With
Shutdown Select
General Description
The LM4898 is a fully differential audio power amplifier
primarily designed for demanding applications in mobile
phones and other portable communication device applica-
tions. 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 5VDC power supply.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4898 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for mobile phone and other low voltage appli-
cations where minimal power consumption is a primary re-
quirement.
The LM4898 features a low-power consumption shutdown
mode. To facilitate this, Shutdown may be enabled by either
logic high or low depending on mode selection. Driving the
shutdown mode pin either high or low enables the shutdown
select pin to be driven in a likewise manner to enable Shut-
down. Additionally, the LM4898 features an internal thermal
shutdown protection mechanism.
The LM4898 contains advanced pop & click circuitry which
virtually eliminates noises which would otherwise occur dur-
ing turn-on and turn-off transitions.
Key Specifications
j Improved PSRR at 217Hz
j Power Output at 5.0V & 1% THD
j Power Output at 3.3V & 1% THD
j Shutdown Current
83dB(typ)
1.0W(typ)
400mW(typ)
0.1µA(typ)
Features
n Fully differential amplification
n Available in space-saving packages micro SMD, MSOP,
and LLP
n Ultra low current shutdown mode
n Can drive capacitive loads up to 500pF
n Improved pop & click circuitry eliminates noises during
turn-on and turn-off transitions
n 2.4 - 5.5V operation
n No output coupling capacitors, snubber networks or
bootstrap capacitors required
n Shutdown high or low selectivity
Applications
n Mobile phones
n PDAs
n Portable electronic devices
Connection Diagrams
Mini Small Outline (MSOP) Package
MSOP Marking
20073723
Top View
Order Number LM4898MM
See NS Package Number MUB10A
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2003 National Semiconductor Corporation DS200737
20073774
Z -Assembly Code
X - Date Code
TT - Die Run Traceability
G - Boomer Family
B3 - LM4898MM
www.national.com
1 page  
Electrical Characteristics VDD = 3V (Notes 1, 2, 8)
The following specifications apply for VDD = 3V, 8Ω load and AV = 1V/V, unless otherwise specified. Limits apply for TA =
25˚C.
Symbol
Parameter
Conditions
IDD Quiescent Power Supply Current
ISD Shutdown Current
Po Output Power
THD+N Total Harmonic Distortion+Noise
PSRR Power Supply Rejection Ratio
CMRR Common-Mode Rejection Ratio
VOS
VSDIH
VSDIL
VSDIH
VSDIL
Output Offset
Shutdown Voltage Input High
Shutdown Voltage Input Low
Shutdown Voltage Input High
Shutdown Voltage Input Low
VIN = 0V, no load
VIN = 0V, RL = 8 Ω
VSDMODE = VSHUTDOWN = GND
THD = 1% (max); f = 1kHz
LM4898, RL = 8Ω
Po = 0.25Wrms; f = 1kHz
Vripple = 200mV sine p-p
f = 217Hz (Note 9)
f = 1kHz (Note 9)
f = 217Hz (Note 10)
f = 1kHz (Note 10)
f = 217Hz
VCM = 200mVPP
VIN = 0V
SD Mode = GND
SD Mode = GND
SD Mode = VDD
SD Mode = VDD
LM4898
Typical
Limit
(Note 6)
(Note 7)
2.5 5 .5
49
0.1 1
0.35
0.03
83
84
83
83
50
2
0.8
0.6
0.8
0.6
Units
(Limits)
mA (max)
µA (max)
W
%
dB
dB
mV
V
V
V
V
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 TJMAX, θJA, and the ambient temperature TA. The maximum
allowable power dissipation is PDMAX = (TJMAX–TA)/θJA or the number given in Absolute Maximum Ratings, whichever is lower.
Note 4: Human body model, 100pF discharged through a 1.5kΩ resistor.
Note 5: Machine Model, 220pF–240pF discharged through all pins.
Note 6: Typicals are measured at 25˚C and represent the parametric norm.
Note 7: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 8: For micro SMD only, shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase ISD by a maximum of 2µA.
Note 9: Unterminated input.
Note 10: 10Ω terminated input.
Note 11: When driving 4Ω loads from a 5V supply, the LM4898LD must be mounted to a circuit board with the exposed-DAP area soldered down to a 1sq. in plane
of 1oz. copper..
External Components Description
(Figure 1)
Components
1. CS
2. CB
3. Ri
4. Rf
Functional Description
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.
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 CB.
Inverting input resistance which sets the closed-loop gain in conjunction with Rf.
Feedback resistance which sets the closed-loop gain in conjunction with Ri.
5 www.national.com
5 Page 
Typical Performance Characteristics
Non-LD Specific Characteristics (Continued)
CMRR vs Frequency
VDD = 5V, RL = 8Ω, 200mVpp
CMRR vs Frequency
VDD = 3V, RL = 8Ω, 200mVpp
200737E8
PSRR vs Common Mode Voltage
VDD = 5V
200737F0
PSRR vs Common Mode Voltage
VDD = 3V, RL = 8Ω, 217Hz, 200mVpp
200737F2
200737F4
Application Information
DIFFERENTIAL AMPLIFIER EXPLANATION
The LM4898 is a fully differential audio amplifier that fea-
tures differential input and output stages. Internally this is
accomplished by two circuits: a differential amplifier and a
common mode feedback amplifier that adjusts the output
voltages so that the average value remains VDD/2. When
setting the differential gain, the amplifier can be considered
to have two "halves". Each half uses an input and feedback
resistor (Ri1 and Rf1) to set its respective closed-loop gain
(see Figure 1). With Ri1 = Ri2 and Rf1 = Rf2, the gain is set
at -Rf/Ri for each half. This results in a differential gain of
AVD = -Rf/Ri
(1)
It is extremely important to match the input resistors to each
other, as well as the feedback resistors to each other for best
amplifier performance. See the Proper Selection of External
Components section for more information. A differential am-
plifier works in a manner where the difference between the
two input signals is amplified. In most applications, this
would require input signals that are 180˚ out of phase with
each other. The LM4898 can be used, however, as a single
ended input amplifier while still retaining its fully differential
benefits. In fact, completely unrelated signals may be placed
on the input pins. The LM4898 simply amplifies the differ-
ence between them.
All of these applications, either single-ended or fully differ-
ential, provide what is known as a "bridged mode" output
(bridge-tied-load, BTL). This results in output signals at Vo1
and Vo2 that are 180˚ out of phase with respect to each
other. Bridged mode operation is different from the single-
ended amplifier configuration that connects the load be-
tween the amplifier output and ground. A bridged amplifier
design has distinct advantages over the single-ended con-
figuration: it provides differential drive to the load, thus dou-
bling maximum possible output swing for a specific supply
voltage. Four times the output power is possible compared
with a single-ended amplifier under the same conditions.
This increase in attainable output power assumes that the
11 www.national.com
11 Page | ||
| Páginas | Total 17 Páginas | |
| PDF Descargar | [ Datasheet LM4898ITL.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LM4898ITL | 1 Watt Fully Differential Audio Power Amplifier With Shutdown Select | National Semiconductor |
| LM4898ITLX | 1 Watt Fully Differential Audio Power Amplifier With Shutdown Select | National Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |