LM4910MA National Semiconductor, LM4910MA Datasheet

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LM4910MA

Manufacturer Part Number
LM4910MA
Description
Output Capacitor-less Stereo 35mW Headphone Amplifier
Manufacturer
National Semiconductor
Datasheet
© 2003 National Semiconductor Corporation
LM4910
Output Capacitor-less Stereo 35mW Headphone
Amplifier
General Description
The LM4910 is an audio power amplifier primarily designed
for headphone applications in portable device applications. It
is capable of delivering 35mW of continuous average power
to a 32Ω load with less than 1% distortion (THD+N) from a
3.3V
The LM4910 utilizes a new circuit topology that eliminates
output coupling capacitors and half-supply bypass capaci-
tors (patent pending). The LM4910 contains advanced pop &
click circuitry which eliminates noises caused by transients
that would otherwise occur during turn-on and turn-off.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. Since the LM4910 does not require
any output coupling capacitors, half-supply bypass capaci-
tors, or bootstrap capacitors, it is ideally suited for low-power
portable applications where minimal space and power con-
sumption are primary requirements.
The LM4910 features a low-power consumption shutdown
mode, activated by driving the shutdown pin with logic low.
Additionally, the LM4910 features an internal thermal shut-
down protection mechanism. The LM4910 is also unity-gain
stable and can be configured by external gain-setting resis-
tors.
Typical Application
Boomer
DC
®
is a registered trademark of National Semiconductor Corporation.
power supply.
FIGURE 1. Typical Audio Amplifier Application Circuit
DS200305
Key Specifications
n PSRR at f = 217Hz
n Power Output at V
n Shutdown Current
Features
n Eliminates headphone amplifier output coupling
n Eliminates half-supply bypass capacitor (patent pending)
n Advanced pop & click circuitry eliminates noises during
n Ultra-low current shutdown mode
n Unity-gain stable
n 2.2V - 5.5V operation
n Available in space-saving MSOP, LLP, and SOIC
Applications
n Mobile Phones
n PDAs
n Portable eletronics devices
n Portable MP3 players
1%
capacitors (patent pending)
turn-on and turn-off
packages
DD
20030565
= 3.3V, R
L
= 32Ω, and THD ≤
February 2003
www.national.com
35mW (typ)
0.1µA (typ)
65dB (typ)

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LM4910MA Summary of contents

Page 1

... The LM4910 is also unity-gain stable and can be configured by external gain-setting resis- tors. Typical Application FIGURE 1. Typical Audio Amplifier Application Circuit Boomer ® registered trademark of National Semiconductor Corporation. © 2003 National Semiconductor Corporation Key Specifications n PSRR 217Hz n Power Output Shutdown Current ...

Page 2

... Connection Diagrams www.national.com MSOP/SO Package 20030502 Top View Order Number LM4910MM or LM4910MA See NS Package Number MUA08A or M08A MSOP Marking 20030566 Top View G - Boomer Family C2 - LM4910MM SO Marking 20030567 Top View TT - Die Traceability Bottom 2 lines - Part Number LLP Package 20030595 Top View Order Number LM4910LQ ...

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 (Note 9) Storage Temperature Input Voltage Power Dissipation (Note 3) ESD Susceptibility Pin 6 (Note 10) ESD Susceptibility (Note 4) ESD Susceptibility (Note 5) Junction Temperature ...

Page 4

Electrical Characteristics V The following specifications apply for V Symbol Parameter I Quiescent Power Supply Current DD I Standby Current SD V Output Offset Voltage OS P Output Power O THD+N Total Harmonic Distortion + Noise P PSRR Power Supply ...

Page 5

Typical Performance Characteristics THD+N vs Frequency THD+N vs Frequency THD+N vs Frequency THD+N vs Frequency 20030506 THD+N vs Frequency 20030508 THD+N vs Frequency 20030510 5 20030507 20030509 20030511 www.national.com ...

Page 6

Typical Performance Characteristics THD+N vs Output Power THD+N vs Output Power THD+N vs Output Power www.national.com (Continued) THD+N vs Output Power 20030516 THD+N vs Output Power 20030515 THD+N vs Output Power 20030519 6 20030517 20030518 20030520 ...

Page 7

Typical Performance Characteristics Output Power vs Load Resistance Output Power vs Supply Voltage Output Power vs Supply Voltage (Continued) 20030523 20030579 Power Dissipation vs 20030581 7 Output Power vs Load Resistance 20030578 Output Power vs Supply Voltage 20030580 Output Power ...

Page 8

Typical Performance Characteristics Power Dissipation vs Output Power Channel Separation Power Supply Rejection Ratio www.national.com (Continued) Power Dissipation vs 20030582 Power Supply Rejection Ratio 20030583 Power Supply Rejection Ratio 20030584 8 Output Power 20030529 20030535 20030585 ...

Page 9

Typical Performance Characteristics Open Loop Frequency Response Frequency Response vs Input Capacitor Size (Continued) 20030586 Supply Current vs Supply Voltage 20030588 9 Noise Floor 20030587 20030589 www.national.com ...

Page 10

Application Information ELIMINATING OUTPUT COUPLING CAPACITORS Typical single-supply audio amplifiers that drive single- ended (SE) headphones use a coupling capacitor on each SE output. This output coupling capacitor blocks the half- supply voltage to which the output amplifiers are typically ...

Page 11

Application Information headphone operation (32Ω impedance) using a 3.3V supply the maximum power dissipation is only 138mW. Therefore, power dissipation is not a major concern. POWER SUPPLY BYPASSING As with any amplifier, proper supply bypassing is important for low noise ...

Page 12

Application Information From Equation 2, the minimum A is 0.98; use A V the desired input impedance is 20kΩ, and with A a ratio of 1:1 results from Equation 1 for R are chosen with R = 20kΩ and R ...

Page 13

Application Information ESD PROTECTION As stated in the Absolute Maximum Ratings, pin 6 (V the LM4910 has a maximum ESD susceptibility rating of 10kV. For higher ESD voltages, the addition of a PCDN042 FIGURE 4. The PCDN042 provides additional ESD ...

Page 14

Application Information HIGHER GAIN AUDIO AMPLIFIER www.national.com (Continued) Output Power vs R SERIES FIGURE 6. FIGURE 7. 14 20030591 20030593 ...

Page 15

Application Information The LM4910 is unity-gain stable and requires no external components besides gain-setting resistors, input coupling capacitors, and proper supply bypassing in the typical appli- cation. However very large closed-loop differential gain is required, a feedback capacitor ...

Page 16

Application Information LM4910 SO DEMO BOARD ARTWORK Composite View Top Layer www.national.com (Continued) 20030570 20030572 16 Silk Screen 20030571 Bottom Layer 20030573 ...

Page 17

Application Information LM4910 MSOP DEMO BOARD ARTWORK Composite View Top Layer (Continued) 20030574 20030576 17 Silk Screen 20030575 Bottom Layer 20030577 www.national.com ...

Page 18

Application Information LM4910 LLP DEMO BOARD ARTWORK Composite View Top Layer www.national.com (Continued) 20030597 20030599 18 Silk Screen 20030598 Bottom Layer 20030596 ...

Page 19

Application Information LM4910 Reference Design Boards Bill of Materials Part Description LM4910 Mono Reference Design Board LM4910 Audio AMP Tantalum Cap 1µF 16V 10 Ceramic Cap 0.39µF 50V Z50 20 Resistor 20kΩ 1/10W 5 Resistor 100kΩ 1/10W 5 Jumper Header ...

Page 20

Physical Dimensions www.national.com inches (millimeters) unless otherwise noted MSOP Order Number LM4910MM NS Package Number MUA08A 20 ...

Page 21

... Physical Dimensions inches (millimeters) unless otherwise noted (Continued) SO Order Number LM4910MA NS Package Number M08A LQ Order Number LM4910LQ NS Package Number LQB08A 21 www.national.com ...

Page 22

... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...

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