LM4924SDBD National Semiconductor, LM4924SDBD Datasheet

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LM4924SDBD

Manufacturer Part Number
LM4924SDBD
Description
BOARD EVALUATION LM4924SD
Manufacturer
National Semiconductor
Series
Boomer®r
Datasheet

Specifications of LM4924SDBD

Amplifier Type
Class AB
Output Type
Headphones, 2-Channel (Stereo)
Max Output Power X Channels @ Load
40mW x 2 @ 16 Ohm
Voltage - Supply
1.5 V ~ 3.6 V
Operating Temperature
-40°C ~ 85°C
Board Type
Fully Populated
Utilized Ic / Part
LM4924
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
© 2009 National Semiconductor Corporation
2 Cell Battery, 40mW Per Channel Output Capacitor-Less
(OCL) Stereo Headphone Audio Amplifier
General Description
The LM4924 is a Output Capacitor-Less (OCL) stereo head-
phone amplifier, which when connected to a 3.0V supply,
delivers 40mW per channel to a 16Ω load with less than 1%
THD+N.
With the LM4924 packaged in the MM and SD packages, the
customer benefits include low profile and small size. These
packages minimizes PCB area and maximizes output power.
The LM4924 features circuitry that reduces output transients
(“clicks” and “pops”) during device turn-on and turn-off, and
Mute On and Off. An externally controlled, low-power con-
sumption, active-low shutdown mode is also included in the
LM4924. Boomer audio power amplifiers are designed specif-
ically to use few external components and provide high quality
output power in a surface mount packages.
Typical Application
Boomer® is a registered trademark of National Semiconductor Corporation.
201210
FIGURE 1. Block Diagram
LM4924
Key Specifications
Features
Applications
OCL output power
Micropower shutdown current
Supply voltage operating range
PSRR 100Hz, V
2-cell 1.5V to 3.6V battery operation
OCL mode for stereo headphone operation
Unity-gain stable
“Click and pop” suppression circuitry for shutdown On and
Off transients
Active low micropower shutdown
Thermal shutdown protection circuitry
Portable two-cell audio products
Portable two-cell electronic devices
(R
L
= 16Ω, V
DD
DD
20121057
= 3.0V, THD+N = 1%)
= 3.0V, A
V
= 2.5
1.5V < V
www.national.com
June 1, 2009
40mW (typ)
0.1µA (typ)
66dB (typ)
DD
< 3.6V

Related parts for LM4924SDBD

LM4924SDBD Summary of contents

Page 1

... LM4924. Boomer audio power amplifiers are designed specif- ically to use few external components and provide high quality output power in a surface mount packages. Typical Application Boomer® registered trademark of National Semiconductor Corporation. © 2009 National Semiconductor Corporation LM4924   Key Specifications ■ ...

Page 2

Connection Diagrams MSOP Package Top View Order Number LM4924MM See NS Package Number MUB10A for MSOP SD Package Top View Order Number LM4924SD See NS Package Number SDA10A www.national.com 20121058 Bottom Line - Part Number 20121052 2 MSOP Marking 20121006 ...

Page 3

Typical Connections FIGURE 2. Typical OCL Output Configuration Circuit 20121059 3 www.national.com ...

Page 4

... 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 2) ESD Susceptibility(Note 3) ESD Susceptibility on pin 7, 8, and 9 (Note 3) ESD Susceptibility (Note 4) Junction Temperature ...

Page 5

Symbol Parameter PSRR Power Supply Rejection Ratio 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 ...

Page 6

Typical Performance Characteristics THD+N vs Frequency V = 1.8V 5mW THD+N vs Frequency V = 3.0V 10mW www.national.com = 16Ω 20121013 = 16Ω 20121015 6 THD+N ...

Page 7

THD+N vs Output Power = 16Ω 1kHz V = 1.8V 20121017 THD+N vs Output Power = 16Ω 1kHz V = 3.0V 20121019 THD+N vs Output Power = 32Ω ...

Page 8

Power Supply Rejection Ratio V = 1.8V Vripple = 200mVp-p, Input Terminated into 10Ω load Noise Floor V = 1.8V www.national.com = 16Ω, Vripple = 200mVp-p, Input Terminated into 10Ω load 20121011 = 16Ω ...

Page 9

Channel Sepration = 16Ω Output Power vs Supply Voltage = 16Ω, from top to bottom THD+N = 10%; THD Output Power vs Load Resistance f = 1kHz. from top to bottom 3.0V, ...

Page 10

Power Dissipation vs Output Power V = 1.8V 1kHz, from top to bottom 16Ω Supply Current vs Supply Voltage www.national.com V = 32Ω 20121024 20121026 10 Power Dissipation vs Output Power = ...

Page 11

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

Page 12

The trigger point is 0.4V (max) for a logic-low level, and 1.5V (min) for a logic-high level. The low 0.1µA (typ) shutdown current is achieved by applying a voltage that is as ...

Page 13

The result is π 1/(2 *20kΩ*20Hz) = 0.397µF Use a 0.39µF capacitor, the closest standard value. The high frequency pole is determined by the product of the desired frequency pole and the differential gain HIGHER GAIN ...

Page 14

The LM4924 is unity-gain stable and requires no external components besides gain-setting resistors, input coupling ca- pacitors, and proper supply bypassing in the typical applica- tion. However very large closed-loop differential gain is required, a feedback capacitor (C ...

Page 15

PCB LAYOUT GUIDELINES This section provides practical guidelines for mixed signal PCB layout that involves various digital/analog power and ground traces. Designers should note that these are only "rule-of-thumb" recommendations and the actual results will depend heavily on the final ...

Page 16

Physical Dimensions www.national.com inches (millimeters) unless otherwise noted MSOP Package Order Number LM4924MM NS Package Number MUB10A SD Package Order Number LM4924SD NS Package Number SDA10A 16 ...

Page 17

Notes 17 www.national.com ...

Page 18

... For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers www.national.com/amplifiers Audio www.national.com/audio Clock and Timing www.national.com/timing Data Converters www.national.com/adc Interface www.national.com/interface LVDS www.national.com/lvds Power Management www.national.com/power Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www ...

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