lm4668mhx National Semiconductor Corporation, lm4668mhx Datasheet

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lm4668mhx

Manufacturer Part Number
lm4668mhx
Description
10w High-efficiency Mono Btl Audio Power Amplifier
Manufacturer
National Semiconductor Corporation
Datasheet
© 2004 National Semiconductor Corporation
LM4668
10W High-Efficiency Mono BTL Audio Power Amplifier
General Description
The LM4668 is a high efficiency switching audio power
amplifier primarily designed for demanding applications in
flat panel monitors and TV’s. It is capable of delivering 6W to
an 8Ω mono BTL load with less than 1% distortion (THD+N)
from a 12V
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4668 features a micro-power,
active-low shutdown mode, an internal thermal shutdown
protection mechanism, and short circuit protection.
The LM4668 contains advanced transient (“pop and click”)
suppression circuitry that eliminates noises that would oth-
erwise occur during turn-on and turn-off transitions.
Connection Diagrams
Boomer
®
is a registered trademark of National Semiconductor Corporation.
DC
See NS Package Number LDC14A
power supply.
Order Number LM4668LD
LD Package
Top View
DS200891
20089102
Key Specifications
Features
n Soft-start circuitry eliminates noise during turn-on
n Low current shutdown mode
n Low quiescent current
n 6W BTL output, R
n Short circuit protection
n Fixed, internally set gain of 30dB
Applications
n Flat Panel Monitors
n Flat Panel TVs
n Computer Sound Cards
j
j
j
j
j
transition
f
R
IN
Power Output BTL (V
Quiescent Power Supply Current
Efficiency (V
Shutdown Current
Fixed Gain
L
= 1kHz, THD+N = 10%, R
= 8Ω, P
See NS Package Number MXA20A
OUT
Order Number LM4668MH
DD
= 6W)
= 12V, f
L
= 8Ω
MH Package
Top View
DD
IN
= 14V,
= 1kHz,
L
= 8Ω)
200891G3
October 2004
0.15mA (typ)
www.national.com
30mA (typ)
30dB (typ)
10W (typ)
79% (typ)

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lm4668mhx Summary of contents

Page 1

... Connection Diagrams LD Package Top View Order Number LM4668LD See NS Package Number LDC14A Boomer ® registered trademark of National Semiconductor Corporation. © 2004 National Semiconductor Corporation Key Specifications j Power Output BTL ( 1kHz, THD ...

Page 2

Typical Application FIGURE 1. Typical Audio Amplifier Application Circuit (* Zetex ZHCS506) www.national.com 2 20089101 ...

Page 3

Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Storage Temperature Input Voltage Power Dissipation (Note 3) ESD Susceptibility (Note 4) ESD Susceptibility (Note 5) Electrical ...

Page 4

... Electrical Characteristics for the LM4668 Note 8: Datasheets min/max specification limits are guaranteed by design, test, or statistical analysis. Note 9: Shutdown current is measured in a normal room environment. The SHUTDOWN pin should be driven as close as possible to GND for minimum shutdown current. Note 10: Please refer to “Under Voltage Protection” on page 8 under “General Features.” ...

Page 5

Typical Performance Characteristics Amplifier Output Power vs Power Supply Voltage R = 8Ω 1kHz L Power Rejection Ratio vs Frequency 8Ω, Input Referred DD L Power Rejection Ratio vs Frequency V = 14V, ...

Page 6

Typical Performance Characteristics Amplifier Power Dissipation vs Load Power Dissipation V = 12V 8Ω 1kHz DD L Output Power vs Load Resistance V = 14V 1kHz DD Output Power vs Load Resistance V = ...

Page 7

Typical Performance Characteristics Power Dissipation vs Ambient Temperature (Continued) 20089124 7 www.national.com ...

Page 8

General Features SYSTEM FUNCTIONAL INFORMATION Modulation Technique Unlike typical Class D amplifiers that use single-ended com- parators to generate a pulse-width modulated switching waveform and RC timing circuits to set the switching fre- quency, the LM4668 uses a balanced differential ...

Page 9

Application Hints (Continued) nominal cutoff frequency of 47kHz. This cutoff frequency ensures that the attenuation is much less than 3dB at 20kHz. The output filter cutoff frequency and topology are also optimized for operational efficiency. A higher cutoff frequency compromises ...

Page 10

Demonstration Board Layout www.national.com FIGURE 2. Recommended MH PCB Layout Top Silkscreen FIGURE 3. Recommended MH PCB Layout Top Layer 10 20089103 20089104 ...

Page 11

Demonstration Board Layout (Continued) FIGURE 4. Recommended MH PCB Layout Bottom Layer FIGURE 5. Recommended LD PCB Layout Top Silkscreen Layer 11 20089105 20089125 www.national.com ...

Page 12

Demonstration Board Layout www.national.com (Continued) FIGURE 6. Recommended LD PCB Layout Top Layer FIGURE 7. Recommended LD PCB Layout Bottom Layer 12 20089126 20089127 ...

Page 13

Physical Dimensions inches (millimeters) unless otherwise noted LD Package Order Number LM4668LD NS Package Number LDC14A 13 www.national.com ...

Page 14

Physical Dimensions inches (millimeters) unless otherwise noted (Continued) National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry ...

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