National-Semiconductor-LM4843MH.pdf资源-CSDN文库

需积分: 5 194 浏览量 2022-12-03 19:24:56 上传评论 4 收藏 553KB PDF 举报

资源推荐

资源详情

资源评论

LM4843

Stereo 2W Audio Power Amplifiers

with DC Volume Control

General Description

The LM4843 is a monolithic integrated circuit that provides

DC volume control, and stereo bridged audio power amplifi-

ers capable of producing 2W into 4Ω (Note 1) with less than

1.0% THD or 2.2W into 3Ω (Note 2) with less than 1.0%

THD.

Boomer

audio integrated circuits were designed specifically

to provide high quality audio while requiring a minimum

amount of external components. The LM4843 incorporates a

DC volume control with stereo bridged audio power amplifi-

ers making it optimally suited for multimedia monitors, por-

table radios, desktop, and portable computer applications.

The LM4843 features an externally controlled, low-power

consumption shutdown mode, and both a power amplifier

and headphone mute for maximum system flexibility and

performance.

Note 1: When properly mounted to the circuit board, the LM4843MH will

deliver 2W into 4Ω. See the Application Information section for LM4843MH

usage information.

Note 2: LM4843MH that has been properly mounted to the circuit board and

forced-air cooled will deliver 2.2W into 3Ω.

Key Specifications

n P

at 1% THD+N

n into 3Ω 2.2W (typ)

n into 4Ω 2.0W (typ)

n into 8Ω 1.1W (typ)

n Shutdown current 0.7µA (typ)

Features

n Acoustically Enhanced DC Volume Control Taper

n Stereo bridged power amplifiers

n “Click and pop” suppression circuitry

n Thermal shutdown protection circuitry

Applications

n Portable and Desktop Computers

n Multimedia Monitors

n Portable Radios, PDAs, and Portable TVs

Block Diagram

Boomer

is a registered trademark of NationalSemiconductor Corporation.

20038389

FIGURE 1. LM4843 Block Diagram

July 2002

LM4843 Stereo 2W Audio Power Amplifiers with DC Volume Control

Electrical Characteristics for Bridged Mode Operation

(Notes 7, 10) The following specifications apply for V

= 5V, unless otherwise noted. Limits apply for T

= 25˚C.

Symbol Parameter Conditions

LM4843

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

Output Offset Voltage V

= 0V, No Load 10

50 mV (max)

Output Power THD+N=1.0%; f=1kHz; R

=3Ω

(Note 8)

2.2 W

THD+N=1.0%; f=1kHz; R

=4Ω

(Note 9)

THD = 1% (max);f = 1 kHz;

=8Ω

1.1 1.0 W (min)

THD+N = 10%;f = 1 kHz; R

=8Ω 1.5 W

THD+N Total Harmonic Distortion+Noise P

= 1W, 20 Hz

20 kHz,

=8Ω,A

0.3 %

= 340 mW, R

=32Ω 1.0 %

PSRR Power Supply Rejection Ratio C

= 1.0 µF, f = 120 Hz,

RIPPLE

= 200 mVrms; R

=8Ω

74 dB

SNR Signal to Noise Ratio V

= 5V, P

OUT

= 1.1W, R

=8Ω,

A-Wtd Filter

93 dB

talk

Channel Separation f=1kHz, C

= 1.0 µF 70 dB

Note 3: The θ

given is for an MXA20A package whose exposed-DAP is soldered to an exposed 2in

piece of 1 ounce printed circuit board copper.

Note 4: The θ

given is for an MXA20A package whose exposed-DAP is soldered to a 2in

piece of 1 ounce printed circuit board copper on a bottom side layer

through 21 8mil vias.

Note 5: The θ

given is for an MXA20A package whose exposed-DAP is soldered to an exposed 1in

piece of 1 ounce printed circuit board copper.

Note 6: The θ

given is for an MXA20A package whose exposed-DAP is not soldered to any copper.

Note 7: All voltages are measured with respect to the ground pins, unless otherwise specified. All specifications are tested using the typical application as shown

in Figure 1.

Note 8: When driving 3Ω loads from a 5V supply the LM4843MH must be mounted to the circuit board and forced-air cooled.

Note 9: When driving 4Ω loads from a 5V supply the LM4843MH must be mounted to the circuit board.

Note 10: 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. Marshall Chiu feels there are better ways to obtain ’More

Wattage in the Cottage.’ Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device

performance.

Note 11: The maximum power dissipation must be derated at elevated temperatures and is dictated by T

JMAX

, θ

, and the ambient temperature T

. The maximum

allowable power dissipation is P

DMAX

=(T

JMAX

−T

)/θ

. For the LM4843MH, T

JMAX

= 150˚C, and the typical junction-to-ambient thermal resistance, when board

mounted, is 80˚C/W for the MHC20 package.

Note 12: Human body model, 100 pF discharged through a 1.5 kΩ resistor.

Note 13: Machine Model, 220 pF–240 pF discharged through all pins.

Note 14: Typicals are measured at 25˚C and represent the parametric norm.

Note 15: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level). Datasheet min/max specification limits are guaranteed by design, test, or

statistical analysis.