NSC LM4811MM, LM4811LDX, LM4811LD Datasheet

LM4811 Dual 105mW Headphone Amplifier with Digital Volume Control and Shutdown Mode

General Description

The LM4811 is a dual audio power amplifier capable of delivering 105mW per channel of continuous average power into a 16Ω load with 0.1% (THD+N) from a 5V power supply.

Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. Since the LM4811 does not require bootstrap capacitors or snubber networks, it is optimally suited for low-power portable systems.

The LM4811 features a digital volume control that sets the amplifier’s gain from +12dB to −33dB in 16 discrete steps using a two−wire interface.

The unity-gain stable LM4811 also features an externally controlled, active-high, micropower consumption shutdown mode. It also has an internal thermal shutdown protection mechanism.

Key Specifications

n THD+N at 1kHz, 105mW continuous average output

power into 16Ω 0.1% (typ)

n THD+N at 1kHz, 70mW continuous average power into

32Ω 0.1% (typ)

n Shutdown Current 0.3µA (typ)

Features

n Digital volume control range from +12dB to −33dB n LD and MSOP surface mount packaging n "Click and Pop" suppression circuitry n No bootstrap capacitors required n Low shutdown current

Applications

n Cellular Phones n MP3, CD, DVD players n PDA’s n Portable electronics

Connection Diagrams

MSOP Package

20006102

Top View

Order Number LM4811MM

See NS Package Number MUB10A

LD Package

20006162

Top View

Order Number LM4811LD

See NS Package Number LDA10A

Boomer®is a registered trademark of National Semiconductor Corporation.

December 2002

LM4811 Dual 105mW Headphone Amplifier with Digital Volume Control and Shutdown Mode

Typical Application

20006101

*Refer to the Application Information Section for information concerning proper selection of the input and output coupling capacitors.

FIGURE 1. Typical Audio Amplifier Application Circuit

LM4811

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Absolute Maximum Ratings (Note 1)

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

ESD Susceptibility (Note 3) 2.5kV

ESD Susceptibility Machine model (Note 6) 200V

Junction Temperature (T

) 150˚C

Soldering Information

Small Outline Package

Vapor Phase (60 sec.) 215˚C

Infrared (15 sec.) 220˚C

Thermal Resistance

MUB10A 194˚C/W

MUB10A 52˚C/W

LDA10A (Note 7) 63˚C/W

LDA10A (Note 7) 12˚C/W

Operating Ratings

Temperature Range

MIN

≤ TA≤ T

MAX

−40˚C ≤ TA≤ 85˚C

Supply Voltage 2.0V ≤ V

≤ 5.5V

Electrical Characteristics (Notes 1, 8)

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

Symbol Parameter Conditions LM4811 Units

(Limits)

Typical

(Note 4)

Limit

(Note 5)

Supply Voltage 2.0 V (min)

5.5 V (max)

Supply Current VIN= 0V, IO= 0A 1.3 3.0 mA

Shutdown Current VIN= 0V 0.3 µA

Output Offset Voltage VIN= 0V 4.0 50 mV

Output Power 0.1% THD+N; f = 1kHz

=16Ω 105 mW

=32Ω 70 mW

THD+N Total Harmonic Distortion P

= 50mW, RL=32Ω

f = 20Hz to 20kHz

0.3 %

Crosstalk Channel Separation R

=32Ω; f = 1kHz;

= 70mW

100 dB

PSRR Power Supply Rejection Ratio C

= 1.0µF, V

RIPPLE

= 100mV

f = 217Hz

60 dB

(CLOCK, UP/DN, SHUTDOWN) Input Voltage High

1.4 V (min)

(CLOCK, UP/DN, SHUTDOWN) Input Voltage Low

0.4 V (max)

Digital Volume Range Input referred minimum gain −33 dB

Input referred maximum gain +12 dB

Digital Volume Stepsize All 16 discrete steps 3.0 dB

Stepsize Error All 16 discrete steps

0.3 dB

Channel−to−Channel Volume Tracking Error

All gain settings from

−33dB to +12dB

0.15 dB

Shutdown Attenuation Shutdown mode active −100 dB

LM4811

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Electrical Characteristics (Notes 1, 8)

The following specifications apply for VDD= 3.3V unless otherwise specified, limits apply to TA= 25˚C.

Symbol Parameter Conditions LM4811 Units

(Limits)

Typical

(Note 4)

Limit

(Note 5)

Supply Current VIN= 0V, IO= 0A 1.1 mA

Shutdown Current VIN= 0V 0.3 µA

Output Offset Voltage VIN= 0V 4.0 mV

Output Power 0.1% THD+N; f = 1kHz

=16Ω 40 mW

=32Ω 28 mW

THD+N Total Harmonic Distortion P

= 25mW, RL=32Ω

f = 20Hz to 20kHz

0.5 %

PSRR Power Supply Rejection Ratio C

= 1.0µF, V

RIPPLE

= 100mV

f = 217Hz

60 dB

(CLOCK, UP/DN, SHUTDOWN) Input Voltage High

1.4 V (min)

(CLOCK, UP/DN, SHUTDOWN) Input Voltage Low

0.4 V (max)

Digital Volume Range Input referred minimum gain −33 dB

Input referred maximum gain +12 dB

Digital Volume Stepsize All 16 discrete steps 3.0 dB

Stepsize Error All 16 discrete steps

0.3 dB

Channel−to−Channel Volume Tracking Error

All gain settings from

−33dB to +12dB

0.15 dB

Shutdown Attenuation Shutdown mode active −100 dB

Electrical Characteristics (Notes 1, 8)

The following specifications apply for VDD= 2.6V unless otherwise specified, limits apply to TA= 25˚C.

Symbol Parameter Conditions LM4811 Units

(Limits)

Typical

(Note 4)

Limit

(Note 5)

Supply Current VIN= 0V, IO= 0A 1.0 mA

Shutdown Current VIN= 0V 0.3 µA

Output Offset Voltage VIN= 0V 4.0 mV

Output Power 0.1% THD+N; f = 1kHz

=16Ω 20 mW

=32Ω 16 mW

THD+N Total Harmonic Distortion P

= 15mW, RL=32Ω

f = 20Hz to 20kHz

0.6 %

PSRR Power Supply Rejection Ratio C

= 1.0µF, V

RIPPLE

= 100mV

f = 217Hz

60 dB

(CLOCK, UP/DN, SHUTDOWN) Input Voltage High

1.4 V (min)

(CLOCK, UP/DN, SHUTDOWN) Input Voltage Low

0.4 V (max)

Digital Volume Range Input referred minimum gain −33 dB

Input referred maximum gain +12 dB

Digital Volume Stepsize All 16 discrete steps 3.0 dB

Stepsize Error All 16 discrete steps

0.3 dB

Channel−to−Channel Volume Tracking Error

All gain settings from

−33dB to +12dB

0.15 dB

LM4811

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Electrical Characteristics (Notes 1, 8) (Continued)

The following specifications apply for VDD= 2.6V unless otherwise specified, limits apply to TA= 25˚C.

Symbol Parameter Conditions LM4811 Units

(Limits)

Typical

(Note 4)

Limit

(Note 5)

Shutdown Attenuation Shutdown mode active −75 dB

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Note 2: Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and

test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions.

Note 3: Human body model, 100pF discharged through a 1.5kΩ resistor.

Note 4: Typical specifications are specified at +25˚C and represent the most likely parametric norm.

Note 5: Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level). Datasheet min/max specification limits are guaranteed by design, test,

or statistical analysis.

Note 6: : Machine Model ESD test is covered by specification EIAJ IC-121-1981. A 200pF cap is charged to the specified voltage, then discharged directly into the IC with no external series resistor (resistance of discharge path must be under 50 Ohms).

Note 7: The LDA10A package has its Exposed−DAP soldered to an exposed 2in

area of 1oz printed circuit board copper.

Note 8: All voltages are measured with respect to the ground pin, unless otherwise specified.

External Components Description

(Figure 1)

Components Functional Description

1. C

This is the input coupling capacitor. It blocks the DC voltage at, and couples the input signal to, the amplifier’s input terminals. C

also creates a highpass filter with the internal input resistor, Ri,atfc=

1/(2πR

iCi

). The minimum value of Riis 33kΩ. Refer to the section, Proper Selection of External

Components, for an explanation of how to determine the value of C

2. C

This is the supply bypass capacitor. It provides power supply filtering. Refer to the Application Information section for proper placement and selection of the supply bypass capacitor.

3. C

This is the BYPASS pin capacitor. It provides half-supply filtering. Refer to the section, Proper Selection of External Components, for information concerning proper placement and selection of C

4. C

This is the output coupling capacitor. It blocks the DC voltage at the amplifier’s output and it forms a high pass filter with R

at fO= 1/(2πRLCO)

Typical Performance Characteristics

THD+N vs Frequency THD+N vs Frequency

20006103 20006104

LM4811

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Typical Performance Characteristics (Continued)

THD+N vs Frequency THD+N vs Frequency

20006105 20006106

THD+N vs Frequency THD+N vs Frequency

20006107 20006108

THD+N vs Frequency THD+N vs Frequency

20006109 20006110

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