NSC LM4861M, LM4861MX Datasheet

LM4861

1.1W Audio Power Amplifier with Shutdown Mode

General Description

The LM4861 is a bridge-connected audio power amplifier ca­pable of delivering 1.1W of continuous average power to an
8Ω load with 1%(THD) using a 5V power supply.

Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components using surface mount packaging. Since
the LM4861 does not require output coupling capacitors,
bootstrap capacitors, or snubber networks, it is optimally
suited for low-power portable systems.

The LM4861 features an externally controlled, low-power
consumption shutdown mode, as well as an internal thermal
shutdown protection mechanism.

The unity-gain stable LM4861 can be configured by external
gain-setting resistors.

Key Specifications

n THD at 1 kHz at 1W continuous

average output power into 8Ω 1.0%(max)

n Output power at 10%THD+N

at 1 kHz into 8Ω

1.5W (typ)

n Shutdown Current 0.6 µA (typ)

Features

n No output coupling capacitors, bootstrap capacitors, or

snubber circuits are necessary

n Small Outline (SO) packaging
n Compatible with PC power supplies
n Thermal shutdown protection circuitry
n Unity-gain stable
n External Gain Configuration Capability

Applications

n Personal computers
n Portable consumer products
n Self-powered speakers
n Toys and games

Typical Application Connection Diagram

Boomer®is a registered trademark of National Semiconductor Corporation.

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FIGURE 1. Typical Audio Amplifier Application Circuit

Small Outline Package

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Top View

Order Number LM4861M

See NS Package Number M08A

May 1997

LM4861 1.1W Audio Power Amplifier with Shutdown Mode

© 1999 National Semiconductor Corporation DS011986 www.national.com

Absolute Maximum Ratings (Note 2)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage 6.0V
Storage Temperature −65˚C to +150˚C
Input Voltage −0.3V to V

DD

+ 0.3V
Power Dissipation (Note 3) Internally limited
ESD Susceptibility (Note 4) 3000V
ESD Susceptibility (Note 5) 250V
Junction Temperature 150˚C
Soldering Information

Small Outline Package

Vapor Phase (60 sec.)
Infrared (15 sec.)

215˚C
220˚C

See AN-450

“Surface Mounting and their Effects on

Product Reliability”

for other methods of soldering surface

mount devices.

Operating Ratings

Temperature Range

T

MIN

≤ TA≤ T

MAX

−40˚C ≤ TA≤ +85˚C

Supply Voltage 2.0V ≤ V

DD

≤ 5.5V

Thermal Resistance

θ

JC

(typ)— M08A 35˚C/W

θ

JA

(typ)— M08A 140˚C/W

θ

JC

(typ)— N08E 37˚C/W

θ

JA

(typ)— N08E 107˚C/W

Electrical Characteristics (Note 1) (Note 2)

The following specifications apply for VDD= 5V, unless otherwise specified. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4861

Units

(Limits)

Typical Limit

(Note 6) (Note 7)

V

DD

Supply Voltage 2.0 V (min)

5.5 V (max)

I

DD

Quiescent Power Supply Current VIN= 0V, IO= 0A (Note 8) 6.5 10.0 mA (max)

I

SD

Shutdown Current V

pin1=VDD

0.6 10.0 µA (max)

V

OS

Output Offset Voltage VIN= 0V 5.0 50.0 mV (max)

P

O

Output Power THD = 1%(max);f=1kHz 1.1 1.0 W(min)

THD+N Total Harmonic Distortion +

Noise

P

O

= 1Wrms; 20 Hz ≤ f ≤ 20 kHz 0.72

%

PSRR Power Supply Rejection Ratio V

DD

= 4.9V to 5.1V 65 dB

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 func-

tional, 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 T

JMAX

, θJA, and the ambient temperature TA. The maximum

allowable power dissipation is P

DMAX

=(T

JMAX−TA

)/θJAor the number given in the Absolute Maximum Ratings, whichever is lower. For the LM4861, T

JMAX

= 150˚C,

and the typical junction-to-ambient thermal resistance, when board mounted, is 140˚C/W.

Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 5: Machine Model, 220 pF–240 pF discharged through all pins.
Note 6: Typicals are measured at 25˚C and represent the parametric norm.
Note 7: Limits are guaranteed to Nationai’s AOQL (Average Outgoing Quality Level).
Note 8: The quiescent power supply current depends on the offset voltage when a practical load is connected to the amplifier.

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High Gain Application Circuit

Single Ended Application Circuit

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FIGURE 2. Audio Ampiifier with AVD=20

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*CSand CBsize depend on specific application requirements and constraints. Typical vaiues of CSand CBare 0.1 µF.
**Pin 1 should be connected to V

DD

to disable the amplifier or to GND to enable the amplifier. This pin should not be left floating.

***These components create a “dummy” load for pin 8 for stability purposes.

FIGURE 3. Single-Ended Amplifier with AV=−1

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